Author: "Unité Dyneco, Laboratoire Pelagos" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Unité Dyneco, Laboratoire Pelagos"' showing total 42 results

Start Over Author "Unité Dyneco, Laboratoire Pelagos"

42 results on '"Unité Dyneco, Laboratoire Pelagos"'

1. Pelagic diatoms communicate through synchronized beacon natural fluorescence signaling

Author: Montaño, Jennifer, Coco, Giovanni, Chataigner, Teddy, Yates, Marissa, Le Dantec, Nicolas, Suanez, Serge, Cagigal, Laura, Floc'H, France, Townend, Ian, Wulf, Sabine, Çağatay, M. Namık, Appelt, Oona, Eriş, K. Kadir, Henry, Pierre, Font-Muñoz, Joan, Sourisseau, Marc, Cohen-Sánchez, Amanda, Tuval, Idan, Basterretxea, Gotzon, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Brest (UBO), and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021
Full Text: View/download PDF

2. Spatial Variability of Organic Matter and Phosphorus Cycling in Rhône River Prodelta Sediments (NW Mediterranean Sea, France): a Model-Data Approach

Author: Karline Soetaert, Bruno Lansard, Karima Khalil, Gaël Monvoisin, Khalid Elkalay, Bruno Bombled, Françoise Andrieux-Loyer, Fatima Ezzahra Ait Ballagh, Christophe Rabouille, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Océan et Interfaces (OCEANIS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), This work was supported by the INSU/EC2CO-MissRhoDia project and the CEDoc cooperation research project between Morocco and France., ANR-11-RSNR-0002,AMORAD,AMORAD1(2011), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Unité Dyneco, Laboratoire Pelagos, and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, Aquatic Science, 01 natural sciences, ne River prodelta, Modelling, 12. Responsible consumption, Mediterranean sea, Dissolved organic carbon, River mouth, Mediterranean Sea, Organic matter, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, chemistry.chemical_classification, Total organic carbon, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, Ecology, Continental shelf, 010604 marine biology & hydrobiology, Phosphorus, Rh&#244, Rhône River prodelta, 6. Clean water, chemistry, 13. Climate action, Environmental chemistry, Environmental science, Sediment
Abstract: The Mediterranean Sea (MS) is a large oligotrophic sea whose productivity is sensitive to riverine nutrient inputs. More specifically, phosphorus (P) river supply is crucial for the MS, with an important role of the estuarine/deltaic filter especially for the storage and recycling in sediments. A benthic dataset from the Rhône River prodelta was used to derive P budgets, by means of an early diagenetic model including the benthic P cycle. The model was fitted to pore water profiles of oxygen, nitrate, sulfate, dissolved inorganic carbon, ammonium, oxygen demand units, dissolved inorganic phosphorus (DIP) and solid data (organic carbon (OC), Fe-bound P, Ca-bound P and organic P). Results indicated that the intensity of biogeochemical processes occurring below the sediment–water interface decreased from the river mouth to the adjacent continental shelf with decreasing integrated rates of OC mineralization (160–10 mmol m−2 day−1). The organic P mineralization was intense near the river mouth and decreased offshore (1196–80 μmol m−2 day−1). Its contribution to DIP release was large (> 90%). Fe-bound P had a key role in transferring P to deeper layers. These deltaic sediments played an important role as a source of regenerated DIP. A significant part of DIP was recycled to the overlying waters (72–94%), representing 25% of the riverine DIP discharge. Simultaneously, 6–28% of DIP produced in sediments was buried as Ca-bound P. Overall, this study highlighted the importance of deltaic sediments as an additional source of DIP to the coastal sea, and a minor but permanent sink of phosphorus as solid P burial.
Published: 2021
Full Text: View/download PDF

3. Fossil maerl beds as coastal indicators of late Holocene palaeo-environmental evolution in the Bay of Brest (Western France)

Author: Clément Lambert, Pascal Le Roy, Angélique Roubi, Muriel Vidal, Jacques Grall, Axel Ehrhold, Théo Reixach, Gwenael Jouet, Gwendoline Gregoire, Raffaele Siano, Aurélie Penaud, Jérôme Goslin, Stephan J. Jorry, Laboratoire Géodynamique et enregistrement Sédimentaire - Geosciences Marines (GM-LGS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), UMS 3113, Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LabexMER Marine Excellence Research: a changing ocean, and ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010)
Subjects: 010504 meteorology & atmospheric sciences, Stratigraphy, Rhodolith, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Brittany, Lithothamnion corallioides, 14. Life underwater, Maerl, Ecology, Evolution, Behavior and Systematics, Holocene, 0105 earth and related environmental sciences, Earth-Surface Processes, Storm impact, geography, geography.geographical_feature_category, biology, Estuarine sedimentation, MESH: Brittany, Rhodoliths, Paleontology, Coralline algae, Estuary, Sedimentation, biology.organism_classification, 13. Climate action, [SDE]Environmental Sciences, Period (geology), Bay, Geology
Abstract: International audience; The Bay of Brest (BB) is a mixed, tide-dominated estuarine system. The shore terraces of this bay are occupied by modern free-living (calcareous) coralline algae locally termed “maerl”, organized in bed-like morphologies (rhodolith deposits). Cores retrieved from around the bay reveal fossilized primitive maerl beds of Holocene age, interbedded in sandy-silt sedimentation. The alternation between biogenic constructions and estuarine sedimentation may provide evidence of varying environmental conditions of the late-Holocene period. This paper mainly focuses on the results of chronostratigraphic and bio-sedimentological interpretations of coring data collected in less than 15 m of water depth in an attempt to decipher the main stages of maerl colonization in the bay. In particular, this study raises several significant points allowing to draw links between centennial to millennial-scale climatic changes in marine estuary sedimentation and episodes within the development of maerl biocenoses. The paleo-bathymetry of the coastal terraces has not changed significantly over the last 5000 years. Yet, the first maerl occurrence only appeared around 2000 cal yr B.P., likely showing that the environmental conditions were not favorable for their emergence prior to that time. Pioneer maerl beds developed on coarse shell deposits inherited from the paleostorms affecting the Atlantic coasts during the colder climatic period of the Iron Age (3100–1950 cal yr B.P.). The accumulations then aggraded at various and discontinuous rates, sometimes reaching up to 2.1 m/kyr. Maerl beds temporarily disappeared in the southern part of the Bay of Brest when sedimentation rates increased throughout the bay during the Dark-Age cold period (1375–1250 cal yr B.P.), suggesting that maerl formations could not keep up with sedimentation rate exceeded a certain threshold. Muddy sedimentation conditions also dramatically changed on two occasions, with the establishment of coarse storm levels, set at the intervals 825–600 cal yr B.P. (MWP) and 113–0 cal yr B.P. But maerl deposits reseed the environment as a result of each new cold period, demonstrating the persistence of such coralline algae against drastic palaeoenvironmental changes in coastal areas.
Published: 2021
Full Text: View/download PDF

4. Re-oligotrophication trajectories of macrophyte assemblages in Mediterranean coastal lagoons based on 17-year time-series

Author: Monique Simier, Martin Plus, Vincent Ouisse, Nathalie Malet, Jocelyne Oheix, R. De Wit, Valerie Derolez, I. Le Fur, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), Ecosystèmes lagunaires : organisation biologique et fonctionnement (ECOLAG), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), IFREMER LER/LR, Avenue Jean Monnet, BP 171, 34203 Sète Cedex, France, Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Laboratoire Environnement Ressources Languedoc Roussillon (LERLR), and LITTORAL (LITTORAL)
Subjects: 0106 biological sciences, Mediterranean climate, [SDV]Life Sciences [q-bio], Submerged aquatic vegetation, Aquatic Science, 010603 evolutionary biology, 01 natural sciences, Long-term data series, Regime shift, Recovery, Nutrient reduction, 14. Life underwater, Resilience (network), ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, Series (stratigraphy), Resilience, Ecology, 010604 marine biology & hydrobiology, 15. Life on land, Coastal lagoon, Macrophyte, Oceanography, 13. Climate action, Restoration, [SDE]Environmental Sciences, Environmental science
Abstract: Since the mid-20th century, Mediterranean lagoons have been affected by eutrophication, leading to significant changes in primary producers. In the early 2000s, management actions have been implemented to reduce nutrient inputs with the aim to achieve a good ecological status as requested by the EU water framework directive. As a result of these actions, a sharp decline in nutrient loads has been recorded in several lagoons leading to an oligotrophication of the water column. The analyses of a long-term data set (1998-2015) of 21 polyhaline and euhaline lagoons with contrasting trophic status allowed us to infer a general scheme for the changes in macrophyte assemblages during the oligotrophication process. Placing hypertrophic and oligotrophic conditions end to end, we inferred that the general pattern for the re-oligotrophication trajectory in Mediterranean coastal lagoons is described by the following sequence, with regime shifts between each state: (1) bare non-vegetated sediments, phytoplankton-dominated state; (2) opportunistic macroalgae; (3) seagrass and perennial macroalgae dominated state. However, we did not observe the latter regime shift for the most eutrophicated lagoons, which, so far, remained stuck in the opportunistic macroalgae state. So far, the shift from dominance of opportunistic macroalgae to a system dominated by seagrasses was only observed in a single lagoon where seagrasses had never completely disappeared, which possibly relates to resilience. More generally, the conditions favoring regime shifts from opportunistic macroalgae to seagrasses are still poorly understood. In conclusion, we describe a generic pattern for re-oligotrophication of Mediterranean coastal lagoons, although a full recovery from highly eutrophied to oligotrophic conditions may require more than a decade and may include conditions that remain so far poorly recognized.
Published: 2019
Full Text: View/download PDF

5. Sediment archives reveal irreversible shifts in plankton communities after World War II and agricultural pollution

Author: Nicolas Briant, Véronique Loizeau, Kenneth Neil Mertens, Clément Lambert, Laure Quintric, Cyril Noël, Patrick Durand, Marie Latimier, Raffaele Siano, Sabine Schmidt, Pierre Cuzin, Malwenn Lassudrie, Aurélie Penaud, Axel Ehrhold, Julien Quere, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Environnement Ressources Bretagne Occidentale (LER-BO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Biogéochimie des Contaminants Métalliques (LBCM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre atlantique, Nantes, Biogéochimie des contaminants organiques (LBCO), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), IFREMER-Concarneau, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Laboratoire Environnement Ressource de Bretagne Occidentale (LERBO), LITTORAL (LITTORAL), Biogéochimie et Ecotoxicologie (BE), Laboratoire Biogéochimie des Contaminants Organiques (LBCO), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Géosciences Marines (GM), Laboratoire Environnement Ressource Bretagne Nord (LERBN), and Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Geologic Sediments, World War II, Agricultural pollution, Biodiversity, Biology, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, 0302 clinical medicine, Humans, Marine ecosystem, Ecosystem, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, Retrospective Studies, Ecology, 15. Life on land, Plankton, 030104 developmental biology, Ancient DNA, 13. Climate action, [SDE]Environmental Sciences, Dinoflagellida, Paleoecology, General Agricultural and Biological Sciences, Bay, 030217 neurology & neurosurgery
Abstract: To evaluate the stability and resilience1 of coastal ecosystem communities to perturbations that occurred during the Anthropocene,2 pre-industrial biodiversity baselines inferred from paleoarchives are needed.3,4 The study of ancient DNA (aDNA) from sediments (sedaDNA)5 has provided valuable information about past dynamics of microbial species6, 7, 8 and communities9, 10, 11, 12, 13, 14, 15, 16, 17, 18 in relation to ecosystem variations. Shifts in planktonic protist communities might significantly affect marine ecosystems through cascading effects,19, 20, 21 and therefore the analysis of this compartment is essential for the assessment of ecosystem variations. Here, sediment cores collected from different sites of the Bay of Brest (northeast Atlantic, France) allowed ca. 1,400 years of retrospective analyses of the effects of human pollution on marine protists. Comparison of sedaDNA extractions and metabarcoding analyses with different barcode regions (V4 and V7 18S rDNA) revealed that protist assemblages in ancient sediments are mainly composed of species known to produce resting stages. Heavy-metal pollution traces in sediments were ascribed to the World War II period and coincided with community shifts within dinoflagellates and stramenopiles. After the war and especially from the 1980s to 1990s, protist genera shifts followed chronic contaminations of agricultural origin. Community composition reconstruction over time showed that there was no recovery to a Middle Ages baseline composition. This demonstrates the irreversibility of the observed shifts after the cumulative effect of war and agricultural pollutions. Developing a paleoecological approach, this study highlights how human contaminations irreversibly affect marine microbial compartments, which contributes to the debate on coastal ecosystem preservation and restoration.
Published: 2021
Full Text: View/download PDF

6. Citizen participation in monitoring phytoplankton seawater discolorations

Author: Laure Guillou, Hélène Hégaret, Virginie Antoine, Raffaele Siano, Annie Chapelle, Elisabeth Michel-Guillou, Fabienne Rigaut-Jalabert, Amelia Curd, Aude Leynaert, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Brest (UBO), Centre de Recherches en Psychologie Cognition et Communication (CRPCC EA 1285), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-MEN : EA1285-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (AD2M), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Fédération de recherche de Roscoff (FR2424), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Laboratoire d'Ecologie Benthique Côtière (LEBCO), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)
Subjects: 0106 biological sciences, Economics and Econometrics, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Management, Monitoring, Policy and Law, Aquatic Science, 01 natural sciences, Algal bloom, [SHS]Humanities and Social Sciences, Phytoplankton, Citizen science, Dominance (ecology), 14. Life underwater, Citizen observations, 0105 earth and related environmental sciences, General Environmental Science, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biomass (ecology), biology, 010604 marine biology & hydrobiology, Noctiluca scintillans, ACL, biology.organism_classification, Hazard, Monitoring program, Fishery, 13. Climate action, Seawater discolorations, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Law
Abstract: International audience; A citizen monitoring program (Phenomer) of marine water discolorations caused by high biomass phytoplankton development (Harmful Algal Blooms, HABs) was conducted in 2013, 2014 and 2015 in the coastal waters of Brittany (France). This project aimed to explore the feasibility of acquiring scientifically valuable data on water discolorations phenomena through a citizen science approach, extending the surface area of monitored coastal waters by means of citizen observations. During the three years of the project implementation, respectively 14, 32 and 28 warnings were sampled and recognized as phytoplankton water discolorations. Respectively, 7, 24 and 14 phenomena were observed outside of routine monitoring points. Citizen observations contributed towards evaluating the extension of red discolorations caused by Noctiluca scintillans and the duration and impact on marine fauna of green discolorations of Lepidodinium chlorophorum. A bivalve mortality event coincided with a dark-brown phytoplankton bloom characterized by the dominance of the toxic raphidophytes Heterosigma akashiwo and Pseudochattonella verruculosa, whose presence indicate a new potential hazard in Brittany. Interview analysis of citizen observations showed that the contributors to Phenomer are generally well-informed on environmental issues and concerned about the status of the marine environment. Phenomer demonstrates the complementary value of citizen science programs to routine phytoplankton monitoring, as well as providing scientific information on water discolorations phenomena, whose observations over a large territory have rarely been structured. The advantages and limits shown by the Phenomer project will help to optimize future applications of citizen science approaches for phytoplankton and HAB studies.
Published: 2020
Full Text: View/download PDF

7. Toward a Harmonization for Using in situ Nutrient Sensors in the Marine Environment

Author: Daniel, A., Laës-Huon, A., Barus, C., Beaton, A., Blandfort, D., Guigues, N., Knockaert, M., Munaron, D., Salter, I., Woodward, E., Greenwood, N., Achterberg, E., Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut für Küstenforschung / Institute of Coastal Research, Helmholtz-Zentrum Geesthacht (GKSS), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Alfred Wegener Institute for Polar and Marine Research (AWI), Plymouth Marine Laboratory (PML), Centre for Environment, Fisheries and Aquaculture Science [Lowestoft] (CEFAS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Plymouth Marine Laboratory
Subjects: Global and Planetary Change, EOVs, [SDE.IE]Environmental Sciences/Environmental Engineering, nutrient, Ocean Engineering, Aquatic Science, in situ sensor, Oceanography, In situ sensor, marine biogeochemistry, ocean observing systems, Data comparability, Marine biogeochemistry, Ocean observing systems, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Water Science and Technology, Nutrient, data comparability
Abstract: International audience; Improved comparability of nutrient concentrations in seawater is required to enhance the quality and utility of measurements reported to global databases. Significant progress has been made over recent decades in improving the analysis and data quality for traditional laboratory measurements of nutrients. Similar efforts are required to establish high-quality data outputs from in situ nutrient sensors, which are rapidly becoming integral components of ocean observing systems. This paper suggests using the good practices routine established for laboratory reference methods to propose a harmonized set of deployment protocols and of quality control procedures for nutrient measurements obtained from in situ sensors. These procedures are intended to establish a framework to standardize the technical and analytical controls carried out on the three main types of in situ nutrient sensors currently available (wet chemical analyzers, ultraviolet optical sensors, electrochemical sensors) for their deployments on all kinds of platform. The routine reference controls that can be applied to the sensors are listed for each step of sensor use: initial qualification under controlled conditions in the laboratory, preparation of the sensor before deployment, field deployment and finally the sensor recovery. The fundamental principles applied to the laboratory reference method are then reviewed in terms of the calibration protocol, instrumental interferences, environmental interferences, external controls, and method performance assessment. Data corrections (linearity, sensitivity, drifts, interferences and outliers) are finally identified along with the concepts and calculations for qualification for both real time and time delayed data. This paper emphasizes the necessity of future collaborations between research groups, reference-accredited laboratories, and technology developers, to maintain comparability of the concentrations reported for the various nutrient parameters measured by in situ sensors.
Published: 2020
Full Text: View/download PDF

8. Strong constitutive expression divergence among strains but no evidence of differential expression associated with sexual reproduction in Alexandrium minutum

Author: Yasmine Even, Mickael Le Gac, Julie Seveno, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Mating type, Mating in fungi, Alexandrium minutum, panorama, Plant Science, 010501 environmental sciences, Aquatic Science, Biology, Cyanobacteria, 01 natural sciences, Homology (biology), chemistry.chemical_compound, Gene expression, medicine, Sexual reproduction, UBO, 0105 earth and related environmental sciences, Genetics, Saxitoxin, Mating, 010604 marine biology & hydrobiology, Reproduction, ACL, Dinoflagellate, dinophyceae, sequence, biology.organism_classification, medicine.anatomical_structure, chemistry, Dinoflagellida, Gamete, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, protein, roles, life-cycles
Abstract: WOS:000599869000004; Sexual reproduction remains poorly characterized in dinoflagellates. This is especially the case at the molecular level. Here crossing experiments were performed among strains of the toxic dinoflagellate Alexandrium minutum belonging to two genetically divergent groups. Gene expression was compared between sexually compatible and incompatible crosses at the time of gamete fusion and resting cyst (similar to zygote) formation. Not a single transcript was identified as differentially expressed between compatible and incompatible crosses at these two crucial time points of the dinoflagellate life cycle. However, several thousands of transcripts displayed constitutive expression differences between strains. This was especially the case between the strains belonging to the genetically divergent groups. A few hundreds of transcripts were also identified as differentially expressed between strains belonging to opposite mating types. Some of these transcripts displayed homology with the SxtA protein, known to be involved in saxitoxin production in cyanobacteria, as well as with proteins potentially involved in mating in fungi.
Published: 2020
Full Text: View/download PDF

9. Dinoflagellate fossils: Geological and biological applications

Author: Mélanie Wary, William Hardy, Kenneth Neil Mertens, Thomas Servais, Edwige Masure, Fabienne Marret, Aurélie Penaud, Raffaele Siano, Clément Lambert, Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Department of Geography, University of Liverpool, Paléobiodiversité et paléoenvironnements, Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de paléontologie et paleogéographie du paleozoique (LPPP), Université de Lille, Sciences et Technologies-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), IFREMER-Concarneau, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Évolution, Écologie et Paléontologie (Evo-Eco-Paleo) - UMR 8198 (Evo-Eco-Paléo), Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: 010506 paleontology, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Biostratigraphy, 01 natural sciences, Paleontology, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Dinocyst, Uniformitarianism, 14. Life underwater, Modern dinocyst distribution, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Cyst-motile stage relationship, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Dinoflagellate, Ancient DNA, biology, Plankton, Future climate, biology.organism_classification, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU]Sciences of the Universe [physics], 13. Climate action, [SDE]Environmental Sciences, Paleoecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Quaternary, Geology
Abstract: Dinoflagellates are part of the marine plankton and about 200 species produce a cyst (dinocyst) during their life cycle, these organic-walled sexually-produced cysts being fossilizable in sediments for hundreds of millions of years. Over the past 40–50 years, dinocysts have led to major advances on Mesozoic-Cenozoic research, in terms of biostratigraphy and paleogeogeography. Dinocyst taxonomy has then been continuously revised, with the tabulation being the main morphological link between living dinoflagellates and fossilized cysts. Over the Quaternary, and based on the principle of uniformitarianism (i.e. species ecology did not change through time), relationships between modern assemblages and present-day environmental factors controlling their distribution also allow for dinocyst-based quantitative reconstructions derived from transfer function calculations. This paper presents a non-exhaustive review of the dinocyst literature allowing the reader to get a perspective about how they were discovered and defined, but also how they are applied in (paleo)ecological studies according to the timescale considered allowing then to provide useful insights into the future climate change and its associated ecological repercussions.
Published: 2018
Full Text: View/download PDF

10. Human-induced river runoff overlapping natural climate variability over the last 150 years: Palynological evidence (Bay of Brest, NW France)

Author: Sabine Schmidt, Clément Lambert, Khadidja Klouch, Muriel Vidal, Gwendoline Gregoire, Raffaele Siano, Axel Ehrhold, Olivier Ragueneau, Frédérique Eynaud, Aurélie Penaud, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Laboratoire Géodynamique et enregistrement Sédimentaire - Geosciences Marines (GM-LGS), and Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)
Subjects: 010506 paleontology, 010504 meteorology & atmospheric sciences, Oceanography, 01 natural sciences, Estuarine dynamics, Phytoplankton, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Dinocyst, River runoff, 14. Life underwater, Climate variability, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Palynology, Global and Planetary Change, geography, geography.geographical_feature_category, Dinoflagellate cysts, Acl, Pollen grains, Estuary, 15. Life on land, 13. Climate action, Salt marsh, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Eutrophication, Bay, Surface water, Geology
Abstract: International audience; For the first time a very high resolution palynological study (mean resolution of 1 to 5 years) was carried out over the last 150 years in a French estuarine environment (Bay of Brest; NW France), allowing direct comparison between the evolution of landscapes, surface water, and human practices on Bay of Brest watersheds, through continental (especially pollen grains) and marine (phytoplanktonic microalgae: cysts of dinoflagellates or dinocysts) microfossils. Thanks to the small size of the watersheds and the close proximity of the depositional environment to the mainland, the Bay of Brest represents an ideal case study for palynological investigations. Palynological data were then compared to published palaeo-genetic analyses conducted on the same core and to various available instrumental data, allowing us to better characterize past environmental variability since the second half of the 19th century in Western Brittany. We provide evidence of some clues of recent eutrophication and/or pollution that affected phytoplankton communities and which appears linked with increased runoff (higher precipitations, higher percentages of riparian forest pollen, decline of salt marsh-type indicators, and higher values of the XRF Ti/Ca signal), mainly explained by the evolution of agricultural practices since 1945 superimposed on the warming climate trend. We assume that the significant relay observed between dinocyst taxa: Lingulodinium machaerophorum and Spiniferites bentorii around 1965 then followed by Spiniferites membranaceus after 1985, attests to a strong and recent eutrophication of Bay of Brest surface waters induced by high river runoff combined with abnormally elevated air temperatures, especially obvious in the data from 1990. The structure of the dinocyst community has thus been deeply altered, accompanied by an unprecedented increase of Alexandrium minutum toxic form at the same period, as confirmed by the genetic quantification. Despite this recent major anthropogenic forcing, the fossil pollen sequence also records natural climate variability. We highlight, for the first time, a possible connection between climate (AMO modes) and fossil pollen records (especially tree pollination rates) in coastal sediments using tree percentage fluctuations as an indirect proxy for past sea surface and atmospheric temperatures.
Published: 2018
Full Text: View/download PDF

11. Modélisation des efflorescences de l'algue toxique(Alexandrium minutum) en compétition interspécifique en Rade de Brest, France

Author: Nzeneri, Samuelson, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Bretagne occidentale - Brest, and Annie Chapelle
Subjects: HABs, Efflorescences toxiques (HABs), [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, A. minutum, Physiological traits, Seasonal and interannual variability, Bay of Brest, Variabilité saisonnière et interannuelle, Compétition pour les ressources, Traits physiologiques, Resource competition, Rade de Brest
Abstract: Alexandrium minutum is one of the toxic species that produce Harmful Algal Blooms (HABs), threaten public health, aquaculture and tourism. In France, it was observed in 1988 in the region Bretagne. High levels of Paralytic Shellfish Poisoning (PSP) toxicity have been detected in the estuaries of Morlaix, Penzé, Rance, Abers and more recently, in the Bay of Brest. This work tries to define and place in order of hierarchy, the parameters driving A. minutum success in the phytoplankton community. Two approaches were adopted. The first was a temporal survey at the study site since 2009-2018. The second was the use of a 0D numerical model (based on physiological traits) to simulate the potential impact between physical and biological processes. A. minutum was placed in competition with 72 species which were uniformly selected. Results showed both seasonal and interannual variability of bloom phenology. It was marked by micro, followed by nano and then pico phytoplankton from April to October. A. minutum bloom occurred between June and August, a period of high temperature, low nutrient concentrations and high resource competition. However, environmental factors and competition explain only a part of its phenology. Though the model was able to reproduce the seasonal and interannual variability of A. minutum, simulation was inconsistent over the study period. The model highlights the increasing relevance of other biological processes in bloom regulation at decade scale. It might improve some models which are able to correctly predict instances of A. minutum presence or absence. The perspective is to have a model which can be applied and validated for the entire Bay of Brest.; Alexandrium minutum est un dinoflagellé toxique responsable de crises sanitaires et économiques. En France, cette espèce est observée depuis 1988. Cette étude tente de hiérarchiser les paramètres contrôlant le succès d'A. minutum au sein de la communauté phytoplanctonique par un suivi dans l’estuaire de Daoulas (Rade de Brest) et le développement d’un modèle 0D. Ce modèle basé sur des traits physiologiques met en compétition. A. minutum avec 72 autres espèces réparties de manière uniforme dans l'espace des traits. Les résultats montrent une variabilité saisonnière et inter-annuelle des efflorescences. D’avril à octobre se succèdent le micro puis le nano et enfin le picophytoplancton, contrôlés par la température et la lumière en hiver puis par le phosphore puis l'azote, durant l'été. Les blooms d'A. minutum apparaissent entre juin et août. Les résultats de la modélisation, corroborés par les données, ont montré une efflorescence tardive d’A. minutum lors d’un printemps froid (2013) et précoce lors d’un printemps chaud (2014). Le maximum d’abondance d’A. minutum est observé et simulé en 2012 où les forts débits durant l'été ont entrainé des apports en nutriments très élevés et la plus faible abondance en 2011, été le plus sec sur la période considérée. Le modèle a permis de tester l’impact de scénarios de réduction de 50% d’azote et de phosphore dans les apports. Seule une réduction de phosphore entraîne une diminution de l’abondance d’A. minutum, les apports de la rivière restant très riches en azote. Le modèle n'est toutefois pas consistant sur toute la période d'étude ce qui met en lumière l'importance probable d'autres facteurs dans la régulation des efflorescences.
Published: 2019

12. Modeling the bloom of toxic algae (Alexandrium minutum) in interspecific competition in the Bay of Brest, France

Author: Nzeneri, Samuelson, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Bretagne occidentale - Brest, Annie Chapelle, and STAR, ABES
Subjects: HABs, Efflorescences toxiques (HABs), [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, A. minutum, Physiological traits, Seasonal and interannual variability, [SDV.EE.ECO] Life Sciences [q-bio]/Ecology, environment/Ecosystems, Bay of Brest, Variabilité saisonnière et interannuelle, Compétition pour les ressources, Traits physiologiques, Resource competition, Rade de Brest
Abstract: Alexandrium minutum is one of the toxic species that produce Harmful Algal Blooms (HABs), threaten public health, aquaculture and tourism. In France, it was observed in 1988 in the region Bretagne. High levels of Paralytic Shellfish Poisoning (PSP) toxicity have been detected in the estuaries of Morlaix, Penzé, Rance, Abers and more recently, in the Bay of Brest. This work tries to define and place in order of hierarchy, the parameters driving A. minutum success in the phytoplankton community. Two approaches were adopted. The first was a temporal survey at the study site since 2009-2018. The second was the use of a 0D numerical model (based on physiological traits) to simulate the potential impact between physical and biological processes. A. minutum was placed in competition with 72 species which were uniformly selected. Results showed both seasonal and interannual variability of bloom phenology. It was marked by micro, followed by nano and then pico phytoplankton from April to October. A. minutum bloom occurred between June and August, a period of high temperature, low nutrient concentrations and high resource competition. However, environmental factors and competition explain only a part of its phenology. Though the model was able to reproduce the seasonal and interannual variability of A. minutum, simulation was inconsistent over the study period. The model highlights the increasing relevance of other biological processes in bloom regulation at decade scale. It might improve some models which are able to correctly predict instances of A. minutum presence or absence. The perspective is to have a model which can be applied and validated for the entire Bay of Brest., Alexandrium minutum est un dinoflagellé toxique responsable de crises sanitaires et économiques. En France, cette espèce est observée depuis 1988. Cette étude tente de hiérarchiser les paramètres contrôlant le succès d'A. minutum au sein de la communauté phytoplanctonique par un suivi dans l’estuaire de Daoulas (Rade de Brest) et le développement d’un modèle 0D. Ce modèle basé sur des traits physiologiques met en compétition. A. minutum avec 72 autres espèces réparties de manière uniforme dans l'espace des traits. Les résultats montrent une variabilité saisonnière et inter-annuelle des efflorescences. D’avril à octobre se succèdent le micro puis le nano et enfin le picophytoplancton, contrôlés par la température et la lumière en hiver puis par le phosphore puis l'azote, durant l'été. Les blooms d'A. minutum apparaissent entre juin et août. Les résultats de la modélisation, corroborés par les données, ont montré une efflorescence tardive d’A. minutum lors d’un printemps froid (2013) et précoce lors d’un printemps chaud (2014). Le maximum d’abondance d’A. minutum est observé et simulé en 2012 où les forts débits durant l'été ont entrainé des apports en nutriments très élevés et la plus faible abondance en 2011, été le plus sec sur la période considérée. Le modèle a permis de tester l’impact de scénarios de réduction de 50% d’azote et de phosphore dans les apports. Seule une réduction de phosphore entraîne une diminution de l’abondance d’A. minutum, les apports de la rivière restant très riches en azote. Le modèle n'est toutefois pas consistant sur toute la période d'étude ce qui met en lumière l'importance probable d'autres facteurs dans la régulation des efflorescences.
Published: 2019

13. Reduced phosphorus loads from the Loire and Vilaine rivers were accompanied by increasing eutrophication in the Vilaine Bay (south Brittany, France)

Author: Ratmaya, Widya, Soudant, Dominique, Salmon-Monviola, Jordy, Plus, Martin, Cochennec-Laureau, Nathalie, Goubert, Evelyne, Andrieux-Loyer, Francoise, Barille, Laurent, Souchu, Philippe, LER MPL, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), VIGIES, Sol Agro et hydrosystème Spatialisation (SAS), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), DYNECO PELAGOS, Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, and Université de Nantes (UN)-Université de Nantes (UN)-Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST)
Subjects: spring phytoplankton, phytoplankton community, [SDV]Life Sciences [q-bio], lcsh:QE1-996.5, lcsh:Life, coastal eutrophitocation, seasonal evolution, limitting nutrient, long-term change, lcsh:Geology, lcsh:QH501-531, fresh-water, modeling eutrophication, marine euytophiation, dual nutrient n, lcsh:QH540-549.5, lcsh:Ecology
Abstract: The evolution of eutrophication parameters (i.e., nutrients and phytoplankton biomass) during recent decades was examined in coastal waters of the Vilaine Bay (VB, France) in relation to changes in the Loire and Vilaine rivers. Dynamic linear models were used to study long-term trends and seasonality of dissolved inorganic nutrient and chlorophyll a concentrations (Chl a) in rivers and coastal waters. For the period 1997–2013, the reduction in dissolved riverine inorganic phosphorus (DIP) concentrations led to the decrease in their Chl a levels. However, while dissolved inorganic nitrogen (DIN) concentrations decreased only slightly in the Vilaine, they increased in the Loire, specifically in summer. Simultaneously, phytoplankton in the VB underwent profound changes with increase in biomass and change in the timing of the annual peak from spring to summer. The increase in phytoplankton biomass in the VB, manifested particularly by increased summer diatom abundances, was due to enhanced summer DIN loads from the Loire, sustained by internal regeneration of DIP and dissolved silicate (DSi) from sediments. The long-term trajectories of this case study evidence that significant reduction of P inputs without simultaneous N abatement was not yet sufficient to control eutrophication all along the Loire–Vilaine–VB continuum. Upstream rivers reveal indices of recoveries following the significant diminution of P, while eutrophication continues to increase downstream, especially when N is the limiting factor. More N input reduction, paying particular attention to diffuse N sources, is required to control eutrophication in receiving VB coastal waters. Internal benthic DIP and DSi recycling appears to have contributed to the worsening of summer VB water quality, augmenting the effects of anthropogenic DIN inputs. For this coastal ecosystem, nutrient management strategies should consider the role played by internal nutrient loads to tackle eutrophication processes.
Published: 2019
Full Text: View/download PDF

14. Morphological and genetic diversity of Beaufort Sea diatoms with high contributions from theChaetoceros neogracilisspecies complex

Author: Raffaele Siano, Diana Sarno, Daniel Vaulot, Dominique Marie, Mélanie Chanoine, Isabella Percopo, Sergio Balzano, Priscillia Gourvil, Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Stazione Zoologica Anton Dohrn (SZN), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), MArine Phototrophic Prokaryotes (MAPP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Diversité et Interactions au sein du Plancton Océanique (DIPO), Royal Netherlands Institute for Sea Research (NIOZ), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), and Procaryotes Phototrophes Marins = MArine Phototrophic Prokaryotes (MAPP)
Subjects: 0106 biological sciences, 0301 basic medicine, Canada, Species complex, Nitzschia, Oceans and Seas, Zoology, Plant Science, Aquatic Science, phylogeny, 01 natural sciences, 18S ribosomal RNA, 03 medical and health sciences, ITS2 secondary structure, Microscopy, Electron, Transmission, morphology, Attheya, 14. Life underwater, biogeography, Phylogeny, Diatoms, Cylindrotheca, LSU, Genetic diversity, biology, Arctic Regions, Ecology, 010604 marine biology & hydrobiology, SSU, Genetic Variation, Chaetoceros, Sequence Analysis, DNA, biology.organism_classification, 030104 developmental biology, Diatom, Phytoplankton, Microscopy, Electron, Scanning, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ITS, polar diatoms
Abstract: International audience; Seventy-five diatoms strains isolated from the Beaufort Sea (Canadian Arctic) in the summer of 2009 were characterized by light and electron microscopy (SEM and TEM) as well as 18S and 28S rRNA gene sequencing. These strains group into 20 genotypes and 17 morphotypes and are affiliated with the genera Arcocellulus, Attheya, Chaetoceros, Cylindrotheca, Eucampia, Nitzschia, Porosira, Pseudo-nitzschia, Shionodiscus, Thalassiosira, Synedropsis. Most of the species have a distribution confined to the northern/polar area. Chaetoceros neogracilis and Chaetoceros gelidus were the most represented taxa. Strains of C. neogracilis were morphologically similar and shared identical 18S rRNA gene sequences, but belonged to four distinct genetic clades based on 28S rRNA, ITS-1 and ITS-2 phylogenies. Secondary structure prediction revealed that these four clades differ in hemi-compensatory base changes (HCBCs) in paired positions of the ITS-2, suggesting their inability to interbreed. Reproductively isolated C. neogracilis genotypes can thus co-occur in summer phytoplankton communities in the Beaufort Sea. Chaetoceros neogracilis generally occurred as single cells but can also form short colonies. It is phylogenetically distinct from an Antarctic species, erroneously identified in some previous studies as C. neogracilis but named here as Chaetoceros sp. This work provides taxonomically validated sequences for 20 Arctic diatom taxa, which will facilitate future metabarcoding studies on phytoplankton in this region.
Published: 2016
Full Text: View/download PDF

15. Tidal cycle control of biogeochemical and ecological properties of a macrotidal ecosystem

Author: Cadier, Mathilde, Gorgues, Thomas, L'Helguen, Stéphane, Sourisseau, Marc, Mémery, Laurent, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), and Dynamiques des Écosystèmes Côtiers (DYNECO)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, spring, semidiurnal cycle, ACL, neap tidal cycle, macrotidal ecosystem, phytoplankton communities, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, competition, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, diversity
Abstract: International audience; In some regions, tidal energy can be a key factor in the generation of variability in physical and biogeochemical properties throughout the water column. We use a numerical model resolving tidal cycles and simulating diversity in phytoplankton to assess the impact of tidal mixing on vertical stability and phytoplankton community (total biomass and diversity) in a macrotidal sea (Iroise Sea, France). Two different time scales have been considered: semidiurnal and spring/neap tidal cycles. Our results show that the latter is the one primarily influencing the phytoplankton growth conditions by modifying the vertical stratification. During spring tide, the growth is rather light limited, whereas neap tide conditions lead to vertical stabilization and better light conditions in the shallow surface layer. The transition from high to low tidal mixing conditions is thus associated with a total phytoplankton biomass increase (caused by the rapid development of fast-growing diatoms) and reduced phytoplankton diversity.
Published: 2017
Full Text: View/download PDF

16. Inter and intra-specific growth and domoic acid production in relation to nutrient ratios and concentrations in Pseudo-nitzschia : phosphate an important factor

Author: Mickael Le Gac, Juliette Fauchot, Marie Latimier, Elisabeth Nézan, Kimberley A. Lema, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Station de Biologie Marine de Concarneau, Direction générale déléguée à la Recherche, à l’Expertise, à la Valorisation et à l’Enseignement-Formation (DGD.REVE), Muséum national d'Histoire naturelle (MNHN)-Muséum national d'Histoire naturelle (MNHN), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)
Subjects: 0106 biological sciences, 0301 basic medicine, Genotype, Nitrogen, Harmful Algal Bloom, chemistry.chemical_element, Phosphate, Plant Science, Aquatic Science, 01 natural sciences, Algal bloom, Domoic acid, Phosphates, 03 medical and health sciences, chemistry.chemical_compound, Nutrient, Phytoplankton, Botany, Food science, Ratio, ComputingMilieux_MISCELLANEOUS, Diatoms, Kainic Acid, biology, 010604 marine biology & hydrobiology, Interspecific competition, Nutrients, biology.organism_classification, 030104 developmental biology, chemistry, Pseudo-nitzschia strains, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Pseudo-nitzschia
Abstract: The factors responsible for inducing the synthesis of toxins and responses from toxic phytoplankton blooms remain unclear. In this study we compare the influence of genotypic (at both the intra and interspecific levels) and environmental factors (nutrient concentration and ratio) on growth (in terms of cell densities) and domoic acid (DA) production in three Pseudo-nitzschia species: P. australis, P.pungens and P.fradulenta. A strong phosphate effect was detected. More precisely, a low initial concentration in phosphate, even at high initial nitrogen and silicate concentrations, induced the highest DA concentrations and the lowest cell densities in all strains/species studied. In contrast, a low initial concentration of nitrogen and silicate combined, with a higher phosphate concentration resulted in low cell densities, but without high DA production. Inter-species effects were also observed in DA production, where P. australis represented the most toxigenic species of all. Intra-specific variations were only moderate, except for a recently isolated P. australis strain, suggesting the influence of time since isolation on the physiology and DA production of Pseudo-nitzschia species. Overall, the lack of strong interaction between environmental and genotypic factors showed that the various genotypes investigated did not extensively diverge in their ability to respond (in terms of DA production and cell densities) to contrasting nutrient supply.
Published: 2017
Full Text: View/download PDF

17. Uptake of dissolved inorganic and organic nitrogen by the benthic toxic dinoflagellate Ostreopsis cf. ovata

Author: Cécile Jauzein, Douglas Couet, Thierry Blasco, Rodolphe Lemée, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, inorganic chemicals, Nitrogen, Harmful Algal Bloom, Interactions, chemistry.chemical_element, Uptake, Plant Science, 010501 environmental sciences, Aquatic Science, Biology, 01 natural sciences, chemistry.chemical_compound, Nutrient, Nitrate, Botany, Ammonium, 14. Life underwater, Diel vertical migration, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Nitrogen Isotopes, Dinoflagellate, 010604 marine biology & hydrobiology, food and beverages, Biological Transport, Nutrients, biology.organism_classification, Kinetics, chemistry, Benthic zone, Dinoflagellida, Bay, Ostreopsis
Abstract: International audience; Environmental factors that shape dynamics of benthic toxic blooms are largely unknown. In particular, for the toxic dinoflagellate Ostreopsis cf. ovata, the importance of the availability of nutrients and the contribution of the inorganic and organic pools to growth need to be quantified in marine coastal environments. The present study aimed at characterizing N-uptake of dissolved inorganic and organic sources by O. cf. ovata cells, using the 15N-labelling technique. Experiments were conducted taking into account potential interactions between nutrient uptake systems as well as variations with the diel cycle. Uptake abilities of O. cf. ovata were parameterized for ammonium (NH4+), nitrate (NO3−) and N-urea, from the estimation of kinetic and inhibition parameters. In the range of 0 to 10 μmol N L−1, kinetic curves showed a clear preference pattern following the ranking NH4+ > NO3− > N-urea, where the preferential uptake of NH4+ relative to NO3− was accentuated by an inhibitory effect of NH4+ concentration on NO3− uptake capabilities. Conversely, under high nutrient concentrations, the preference for NH4+ relative to NO3− was largely reduced, probably because of the existence of a low-affinity high capacity inducible NO3− uptake system. Ability to take up nutrients in darkness could not be defined as a competitive advantage for O. cf. ovata. Species competitiveness can also be defined from nutrient uptake kinetic parameters. A strong affinity for NH4+ was observed for O. cf. ovata cells that may partly explain the success of this toxic species during the summer season in the Bay of Villefranche-sur-mer (France).
Published: 2017
Full Text: View/download PDF

18. Assessing spatial and temporal variability of phytoplankton communities' composition in the Iroise Sea ecosystem (Brittany, France): A 3D modeling approach Part 2: Linking summer mesoscale distribution of phenotypic diversity to hydrodynamism

Author: Cadier, Mathilde, Sourisseau, Marc, Gorgues, Thomas, Edwards, Christopher A., Memery, Laurent, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UCSC), University of California, ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, paradox, ACL, Local adaptation, Tidal front, Plankton functional traits, tidal front, Dynamical transport, Biodiversity, respiratory system, stability, patchiness, sub-mesoscale, Biogeography, plankton communities, surface, SOMLIT, chlorophyll, hypothesis, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, competition
Abstract: WOS:000395610500010; International audience; Tidal front ecosystems are especially dynamic environments usually characterized by high phytoplankton biomass and high primary production. However. the description of functional microbial diversity occurring in these regions remains only partially documented. In this article, we use a numerical model, simulating a large number of phytoplankton phenotypes to explore the three-dimensional spatial patterns of phytoplankton abundance and diversity in the Iroise Sea (western Brittany). Our results suggest that, in boreal summer, a seasonally marked tidal front shapes the phytoplankton species richness. A diversity maximum is found in the surface mixed layer located slightly west of the tidal front (i.e., not strictly co-localized with high biomass concentrations) which separates tidally mixed from stratified waters. Differences in phenotypic composition between sub-regions with distinct hydrodynamic regimes (defined by vertical mixing, nutrients gradients and light penetration) are discussed. Local growth and/or physical transport of phytoplankton phenotypes are shown to explain our simulated diversity distribution. We find that a large fraction (64%) of phenotypes present during the considered period of September are ubiquitous, found in the frontal area and on both sides of the front (i.e., over the full simulated domain). The frontal area does not exhibit significant differences between its community composition and that of either the well-mixed region or an offshore Deep Chlorophyll Maximum (DCM). Only three phenotypes (out of 77) specifically grow locally and are found at substantial concentration only in the surface diversity maximum. Thus, this diversity maximum is composed of a combination of ubiquitous phenotypes with specific picoplankton deriving from offshore, stratified waters (including specific phenotypes from both the surface and the DCM) and imported through physical transport, completed by a few local phenotypes. These results are discussed in light of the three-dimensional general circulation at frontal interfaces. Processes identified by this study are likely to be common in tidal front environments and may be generalized to other shallow, tidally mixed environments worldwide.
Published: 2017
Full Text: View/download PDF

19. 3D modeling of phytoplankton seasonal variation and nutrient budget in a southern Mediterranean Lagoon

Author: Noureddine Zaaboub, Lotfi Aleya, Ali Harzallah, Annie Chapelle, Cosimo Solidoro, Béchir Béjaoui, Cristèle Chevalier, Institut National des Sciences et Technologies de la Mer [Salammbô], Istituto Nazionale di Oceanografia e di Geofisica sperimentale ( OGS ), OGS, Natl Inst Marine Sci & Technol, Salammbo, Tunisia, Institut méditerranéen d'océanologie ( MIO ), Institut de Recherche pour le Développement ( IRD ) -Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Centre National de la Recherche Scientifique ( CNRS ), Département Dyneco Pelagos, Institut Français de Recherche pour l'Exploitation de la Mer ( IFREMER ), Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Institut National des Sciences et Technologies de la Mer [Salammbô] (INSTM), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), and Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE)
Subjects: 0106 biological sciences, Mediterranean climate, Biogeochemical cycle, Tunisia, 010504 meteorology & atmospheric sciences, Nitrogen, Aquatic Science, Oceanography, 01 natural sciences, [ SDV.EE ] Life Sciences [q-bio]/Ecology, environment, Coupled hydrodynamic biogeochemical model, Water column, Mediterranean sea, Nutrient, budget, water quality, lagoon, Phytoplankton, Mediterranean Sea, Seawater, 14. Life underwater, Biomass, 0105 earth and related environmental sciences, Water budget, Hydrology, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Coupled hydrodynamic biogeochemical model , Water budget , Nutrient budget, water quality, lagoon, 010604 marine biology & hydrobiology, Water Pollution, Water, Phosphorus, Plankton, Models, Theoretical, Pollution, 6. Clean water, Oxygen, Productivity (ecology), 13. Climate action, Environmental science, Seasons, Environmental Monitoring
Abstract: International audience; A 3D coupled physical-biogeochemical model is developed and applied to Bizerte Lagoon (Tunisia), in order to understand and quantitatively assess its hydrobiological functioning and nutrients budget. The biogeochemical module accounts for nitrogen and phosphorus and includes the water column and upper sediment layer. The simulations showed that water circulation and the seasonal patterns of nutrients, phytoplankton and dissolved oxygen were satisfactorily reproduced. Model results indicate that water circulation in the lagoon is driven mainly by tide and wind. Plankton primary production is co-limited by phosphorus and nitrogen, and is highest in the inner part of the lagoon, due to the combined effects of high water residence time and high nutrient inputs from the boundary. However, a sensitivity analysis highlights the importance of exchanges with the MediterraneanSea in maintaining a high level of productivity. Intensive use of fertilizers in the catchment area has a significant effect on phytoplankton biomass increase.
Published: 2017
Full Text: View/download PDF

20. How competition for resources drive specific niches and community structure of phytoplankton by using a trait-based model

Author: Sourisseau, Marc, Plus, Martin, Chapelle, Annie, Le Guennec, Valérie, Le Gland, Guillaume, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), National Oceanographic Centre [Liverpool] (NOC ), Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Département Dyneco Pelagos, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Dynamiques de l'Environnement Côtier (DYNECO), Laboratoire d'océanographie de Villefranche (LOV), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biological control of artificial ecosystems (BIOCORE), Institut National de la Recherche Agronomique (INRA)-Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'océanographie de Villefranche (LOV), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Alexandrium minutum, niches, ACL, Estuary, Bay of Brest, Droop, panorama, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Inter-specific, competition, phenology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: 00000; International audience; Understanding the phenology of phytoplankton species is still a challenge and despite a lot of theoretical work on competition for ressources this process is under-represented in deterministic models. To study the main driver of the species selection, we thus used a trait-based model that keeps phenotypic variability through physiological trait parameterization. We next validate the results by using a key species, the toxic dinoflagellate Alexandrium minutum. Due to their monitoring, we show that harmful algae are ideal models for studying ecological niches and for contributing to this more global challenge. As a first step, a dimensionless model of an estuary (France) was built with water temperature and water exchanges deduced from a hydro-dynamic model. The biological parametrisation takes into account the size (from pico- to microphytoplankton) and the type of assimilation. The results show that temperature, competition for nutrients and dilution are important factors regulating the community structure and \\textit\Alexandrium minutum\ dynamics (more especially the bloom initiation and magnitude). These drivers contribute to determine the ecological niche of A. minutum, to influence the shape of its blooms and to provide potential explanations of its interannual variability. This approach mainly introduce more flexibility of the community structure to study how environmental forcing could drive its evolution.
Published: 2017
Full Text: View/download PDF

21. High alkaline phosphatase activity in phosphate replete waters: The case of two macrotidal estuaries

Author: Labry, Claire, Delmas, Daniel, Youenou, Agnès, Quere, Julien, Leynaert, Aude, Fraisse, Stéphane, Raimonet, Mélanie, Ragueneau, Olivier, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), EC2CO, French National Program for Coastal Environment, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
Subjects: DYNAMICS, PARTICULATE PHOSPHORUS, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, AVAILABILITY, INORGANIC PHOSPHORUS, ACL, education, LAKE, MARINE-BACTERIA, CARBON, PHYTOPLANKTON, mental disorders, ENZYME-ACTIVITY, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bacteria (microorganisms), [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, psychological phenomena and processes, ORGANIC PHOSPHORUS
Abstract: International audience; The occurrence of alkaline phosphatase activity (APA) that hydrolyses organic phosphorus into phosphate (PO4) is commonly related to PO4 deficiency of oceanic, coastal and fresh waters. APA is almost never investigated in PO4-rich estuaries, since very low activities are expected to occur. As a consequence, microbial mineralization of organic phosphorus into PO4 has often been ignored in estuaries. In this study, we examined the importance of potential APA and the associated microbial dynamics in two estuaries, the Aulne and the Elorn (Northwestern France), presenting two different levels of PO4 concentrations. Unexpected high potential APA was observed in both estuaries. Values ranged from 50 to 506 nmol L−1 h−1, which range is usually found in very phosphorus-limited environments. High potential APA values were observed in the oligohaline zone (salinity 5–15) in spring and summer, corresponding to a PO4 peak and a maximum bacterial production of particle-attached bacteria. In all cases, high potential APA was associated with high suspended particulate matter and total particulate phosphorus. The low contribution of the 0.2–1 μm fraction to total APA, the strong correlation between particulate APA and bacterial biomass, and the close relationship between the production of particle-attached bacteria and APA, suggested that high potential APA is mainly due to particle-attached bacteria. These results suggest that the microbial mineralization of organic phosphorus may contribute to an estuarine PO4 production in spring and summer besides physicochemical processes.
Published: 2016
Full Text: View/download PDF

22. Global change and climate-driven invasion of the Pacific oyster (Crassostrea gigas) along European coasts: a bioenergetics modelling approach

Author: Marianne Alunno-Bruscia, Francis Gohin, Pierre Gernez, Yoann Thomas, Stephane Pouvreau, Laurent Barillé, Philippe Bryere, Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), ACRI-HE, and ANR-12-AGRO-0001,GIGASSAT,Adaptation des écosystèmes ostréicoles au changement global(2012)
Subjects: 0106 biological sciences, Oyster, 010603 evolutionary biology, 01 natural sciences, European coasts, invasive species, biology.animal, Phytoplankton, remote-sensing, Marine ecosystem, 14. Life underwater, functional traits, Ecology, Evolution, Behavior and Systematics, global change, Ecology, biology, 010604 marine biology & hydrobiology, ACL, Global warming, biogeographical range expansion, Global change, 15. Life on land, Pacific oyster, biology.organism_classification, Sea surface temperature, 13. Climate action, Crassostrea gigas, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, DEB model, individual-based model
Abstract: International audience; The spread of non-indigenous species in marine ecosystems world-wide is one of today's most serious environmental concerns. Using mechanistic modelling, we investigated how global change relates to the invasion of European coasts by a non-native marine invertebrate, the Pacific oyster Crassostrea gigas.Location: Bourgneuf Bay on the French Atlantic coast was considered as the northern boundary of C.gigas expansion at the time of its introduction to Europe in the 1970s. From this latitudinal reference, variations in the spatial distribution of the C.gigas reproductive niche were analysed along the north-western European coast from Gibraltar to Norway.Methods: The effects of environmental variations on C.gigas physiology and phenology were studied using a bioenergetics model based on Dynamic Energy Budget theory. The model was forced with environmental time series including insitu phytoplankton data, and satellite data of sea surface temperature and suspended particulate matter concentration.Results: Simulation outputs were successfully validated against insitu oyster growth data. In Bourgneuf Bay, the rise in seawater temperature and phytoplankton concentration has increased C.gigas reproductive effort and led to precocious spawning periods since the 1960s. At the European scale, seawater temperature increase caused a drastic northward shift (1400km within 30years) in the C.gigas reproductive niche and optimal thermal conditions for early life stage development.Main conclusions: We demonstrated that the poleward expansion of the invasive species C.gigas is related to global warming and increase in phytoplankton abundance. The combination of mechanistic bioenergetics modelling with insitu and satellite environmental data is a valuable framework for ecosystem studies. It offers a generic approach to analyse historical geographical shifts and to predict the biogeographical changes expected to occur in a climate-changing world.
Published: 2016
Full Text: View/download PDF

23. Heterogeneous distribution in sediments and dispersal in waters of Alexandrium minutum in a semi-enclosed coastal ecosystem

Author: Florian Caradec, Martin Plus, Lucia Pineau-Guillou, Julien Quere, Annie Chapelle, Raffaele Siano, Z.K. Klouch, T. Hernández-Fariñas, Laure Guillou, Sophie Schmitt, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Diversité et Interactions au sein du Plancton Océanique (DIPO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), and Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Geologic Sediments, 010504 meteorology & atmospheric sciences, Population dynamics, Species distribution, Intertidal zone, Plant Science, [SDV.BID]Life Sciences [q-bio]/Biodiversity, Aquatic Science, Biology, Real-Time Polymerase Chain Reaction, Spatial distribution, DNA, Ribosomal, 01 natural sciences, Molecular ecology, Lagrangian model, Ecosystem, 14. Life underwater, Dinoflagellate cyst, 0105 earth and related environmental sciences, Ecology, 010604 marine biology & hydrobiology, Sediment, Oceanography, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Bays, Dinoflagellida, Biological dispersal, France, Bay, Water Pollutants, Chemical, Environmental Monitoring, Real-time PCR
Abstract: International audience; Within the framework of research aimed at using genetic methods to evaluate harmful species distribution and their impact on coastal ecosystems, a portion of the ITS1rDNA of Alexandrium minutum was amplified by real-time PCR from DNA extracts of superficial (1–3 cm) sediments of 30 subtidal and intertidal stations of the Bay of Brest (Brittany, France), during the winters of 2013 and 2015. Cell germinations and rDNA amplifications of A. minutum were obtained for sediments of all sampled stations, demonstrating that the whole bay is currently contaminated by this toxic species. Coherent estimations of ITS1rDNA copy numbers were obtained for the two sampling cruises, supporting the hypothesis of regular accumulation of A. minutum resting stages in the south-eastern, more confined embayments of the study area, where fine-muddy sediments are also more abundant. Higher ITS1rDNA copy numbers were detected in sediments of areas where blooms have been seasonally detected since 2012. This result suggests that specific genetic material estimations in superficial sediments of the bay may be a proxy of the cyst banks of A. minutum. The simulation of particle trajectory analyses by a Lagrangian physical model showed that blooms occurring in the south-eastern part of the bay are disconnected from those of the north-eastern zone. The heterogeneous distribution of A. minutum inferred from both water and sediment suggests the existence of potential barriers for the dispersal of this species in the Bay of Brest and encourages finer analyses at the population level for this species within semi-enclosed coastal ecosystems.
Published: 2016
Full Text: View/download PDF

24. Contrasting effects of historical contingency on phenotypic and genomic trajectories during a two-step evolution experiment with bacteria

Author: Mickaël Le Gac, Antonia Suau, Dominique Schneider, Claudine Médigue, Stéphane Cruveiller, Jessica Plucain, Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] (LAPM), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Génomique et évolution des microorganismes, Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-IMAG-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Département Dyneco Pelagos, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institute for Advanced Biosciences / Institut pour l'Avancée des Biosciences (Grenoble) (IAB), Centre Hospitalier Universitaire [Grenoble] (CHU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Etablissement français du sang - Auvergne-Rhône-Alpes (EFS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'Ecologie Pélagique (PELAGOS), and Dynamiques des Écosystèmes Côtiers (DYNECO)
Subjects: 0106 biological sciences, 0301 basic medicine, Entomology, Experimental evolution, Escherichia coli, Adaptation, Historical contingency, Epistasis, Population, Biology, Environment, 010603 evolutionary biology, 01 natural sciences, Evolution, Molecular, 03 medical and health sciences, Gene–environment interaction, education, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, Genetics, education.field_of_study, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Replicate, Adaptation, Physiological, 030104 developmental biology, Phenotype, Evolutionary biology, Gene-Environment Interaction, Contingency, Genome, Bacterial, Research Article
Abstract: Background The impact of historical contingency, i.e. the past evolutionary history of a population, on further adaptation is mostly unknown at both the phenotypic and genomic levels. We addressed this question using a two-step evolution experiment. First, replicate populations of Escherichia coli were propagated in four different environmental conditions for 1000 generations. Then, all replicate populations were transferred and propagated for further 1000 generations to a single new environment. Results Using this two-step experimental evolution strategy, we investigated, at both the phenotypic and genomic levels, whether and how adaptation in the initial historical environments impacted evolutionary trajectories in a new environment. We showed that both the growth rate and fitness of the evolved populations obtained after the second step of evolution were contingent upon past evolutionary history. In contrast however, the genes that were modified during the second step of evolution were independent from the previous history of the populations. Conclusions Our work suggests that historical contingency affects phenotypic adaptation to a new environment. This was however not reflected at the genomic level implying complex relationships between environmental factors and the genotype-to-phenotype map., BMC Evolutionary Biology, 16, ISSN:1471-2148
Published: 2016
Full Text: View/download PDF

25. Rapid detection and quantification of the marine toxic algae, Alexandrium minutum, using a super-paramagnetic immunochromatographic strip test

Author: Catherine Dreanno, Julien Quere, Annie Chapelle, Béatrice Baus, Fabienne Gas, CEA Marcoule, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité Dyneco, Laboratoire Pelagos, and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: 0106 biological sciences, Alexandrium minutum, [SDV]Life Sciences [q-bio], Biosensing Techniques, 01 natural sciences, Rapid detection, Analytical Chemistry, Quantification, medicine, Water Pollutants, 14. Life underwater, Toxic algae, Shellfish, ComputingMilieux_MISCELLANEOUS, Immunoassay, Chromatography, medicine.diagnostic_test, Chemistry, 010604 marine biology & hydrobiology, Magnetic Phenomena, 010401 analytical chemistry, Super-paramagnetic, Antibodies, Monoclonal, Dipstick, Eutrophication, medicine.disease, Dipstick lateral flow immunoassay, 0104 chemical sciences, Shellfish poisoning, Nanostructures, Detection, Dinoflagellida, France, Biosensor, Environmental Monitoring
Abstract: The dinoflagellates of Alexandrium genus are known to be producers of paralytic shellfish toxins that regularly impact the shellfish aquaculture industry and fisheries. Accurate detection of Alexandrium including Alexandrium minutum is crucial for environmental monitoring and sanitary issues. In this study, we firstly developed a quantitative lateral flow immunoassay (LFIA) using super-paramagnetic nanobeads for A. minutum whole cells. This dipstick assay relies on two distinct monoclonal antibodies used in a sandwich format and directed against surface antigens of this organism. No sample preparation is required. Either frozen or live cells can be detected and quantified. The specificity and sensitivity are assessed by using phytoplankton culture and field samples spiked with a known amount of cultured A. minutum cells. This LFIA is shown to be highly specific for A. minutum and able to detect reproducibly 10(5)cells/L within 30min. The test is applied to environmental samples already characterized by light microscopy counting. No significant difference is observed between the cell densities obtained by these two methods. This handy super-paramagnetic lateral flow immnunoassay biosensor can greatly assist water quality monitoring programs as well as ecological research.
Published: 2015
Full Text: View/download PDF

26. Evolution and maintenance of haploid-diploid life cycles in natural populations: the case of the marine brown alga Ectocarpus

Author: Couceiro, Lucia, Le Gac, Mickael, Hunsperger, Heather M., Mauger, Stéphane, Destombe, Christophe, Cock, J. Mark, Ahmed, Sophia, Coelho, Susana M, Valero, Myriam, Peters, Akira F, Université Pierre et Marie Curie - Paris 6 (UPMC), Evolutionary Biology and Ecology of Algae (EBEA), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Végétaux marins et biomolécules, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-GOEMAR-Centre National de la Recherche Scientifique (CNRS), Bezhin Rosko, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Ploidy, Asexual reproduction, Sporophyte, Gametophyte, host specificity, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Seaweed, niche differentiation
Abstract: International audience; The evolutionary stability of haploid-diploid life cycles is still controversial. Mathematical models indicate that niche differences between ploidy phases may be a necessary condition for the evolution and maintenance of these life cycles. Nevertheless, experimental support for this prediction remains elusive. In the present work, we explored this hypothesis in natural populations of the brown alga Ectocarpus. Consistent with the life cycle described in culture, E. crouaniorum in NW France and E. siliculosus in SW Italy exhibited an alternation between haploid gametophytes and diploid sporophytes. Our field data invalidated, however, the long-standing view of an isomorphic alternation of generations. Gametophytes and sporophytes displayed marked differences in size and, conforming to theoretical predictions, occupied different spatio-temporal niches. Gametophytes were found almost exclusively on the alga Scytosiphon lomentaria during spring while sporophytes were present year-round on abiotic substrata. Paradoxically, E. siliculosus in NW France exhibited similar habitat usage despite the absence of alternation of ploidy phases. Diploid sporophytes grew both epilithically and epiphytically, and this mainly-asexual population gained the same ecological advantage postulated for haploid-diploid populations. Consequently, an ecological interpretation of the niche differences between haploid and diploid individuals does not seem to satisfactorily explain the evolution of the Ectocarpus life cycle.
Published: 2015
Full Text: View/download PDF

27. Significance of plankton community structure and nutrient availability for the control of dinoflagellate blooms by parasites: a modeling approach

Author: Alves-de-souza, Catharina, Pecqueur, David, Le Floc'H, Emilie, Mas, Sebastien, Roques, Cecile, Mostajir, Behzad, Vidussi, Franscesca, Velo-suarez, Lourdes, Sourisseau, Marc, Fouilland, Eric, Guillou, Laure, Universidade Federal do Rio de Janeiro (UFRJ), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Montpellier 2 - Sciences et Techniques (UM2), Département Dyneco Pelagos, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Diversité et Interactions au sein du Plancton Océanique (DIPO), Adaptation et diversité en milieu marin (ADMM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), Université de Montpellier (UM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS), Unité Dyneco, Laboratoire Pelagos, and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: fungi, lcsh:R, lcsh:Medicine, Numerical Analysis, Computer-Assisted, Eutrophication, Plankton, Models, Biological, Food, parasitic diseases, Dinoflagellida, Animals, Computer Simulation, Parasites, lcsh:Q, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, lcsh:Science, Research Article
Abstract: International audience; Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for infection) or by affecting numerical-functional responses of grazers that consume free-living parasite stages. These outcomes indicate that although both dinoflagellates and their protozoan parasites are directly affected by nutrient availability , the efficacy of the parasitic control of dinoflagellate blooms under temporary eutrophication depends strongly on the structure of the plankton community as a whole.
Published: 2015
Full Text: View/download PDF

28. Biophysical Interactions Control the Size and Abundance of Large Phytoplankton Chains at the Ushant Tidal Front

Author: Louis Marié, Michel Lunven, José María Landeira, Marc Sourisseau, Bruno Ferron, Pascal Morin, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), CHImie Marine (CHIM), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), GIS EUROPOLE MER (http://www.europolemer.eu/en/home.php) and in particular the Axis 2 'Global change, Ocean and Marine Ecosystems' funded the postdoctoral fellowship to JM Landeira. VMP instrumentation was funded by ANR grant ANR-05-JCJC-0153 and IFREMER. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript., Laboratoire d'Ecologie Pélagique (PELAGOS), and Dynamiques des Écosystèmes Côtiers (DYNECO)
Subjects: Chlorophyll, lcsh:Medicine, Marine and Aquatic Sciences, Plant Science, Oceanography, Food chain, Biomass, lcsh:Science, Trophic level, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, Primary producers, biology, Ecology, Geography, [SDV.BA]Life Sciences [q-bio]/Animal biology, Marine Ecology, Temperature, Marine Technology, Plants, Bays, Phycology, France, Seasons, Bloom, Coastal Ecology, Research Article, Pycnocline, Food Chain, Algae, Marine Biology, Ecosystems, Fluorescence, Marine Monitoring, Phytoplankton, Water Movements, 14. Life underwater, Biology, Ecosystem, Diatoms, Population Density, Nitrates, lcsh:R, Videotape Recording, Pelagic zone, biology.organism_classification, Diatom, 13. Climate action, Spain, Earth Sciences, lcsh:Q
Abstract: International audience; Phytoplankton blooms are usually dominated by chain-forming diatom species that can alter food pathways from primary producers to predators by reducing the interactions between intermediate trophic levels. The food-web modifications are determined by the length of the chains; however, the estimation is biased because traditional sampling strategies damage the chains and, therefore, change the phytoplankton size structure. Sedimentological studies around oceanic fronts have shown high concentrations of giant diatom mats (.1 cm in length), suggesting that the size of diatom chains is underestimated in the pelagic realm. Here, we investigate the variability in size and abundance of phytoplankton chains at the Ushant tidal front (NW France) using the Video Fluorescence Analyzer (VFA), a novel and non-invasive system. CTD and Scanfish profiling characterized a strong temperature and chlorophyll front, separating mixed coastal waters from the oceanic-stratified domain. In order to elucidate spring-neap variations in the front, vertical microstructure profiler was used to estimate the turbulence and vertical nitrate flux. Key findings were: (1) the VFA system recorded large diatom chains up to 10.7 mm in length; (2) chains were mainly distributed in the frontal region, with maximum values above the pycnocline in coincidence with the maximum chlorophyll; (3) the diapycnal fluxes of nitrate enabled the maintenance of the bloom in the frontal area throughout the spring-neap tidal cycle; (4) from spring to neap tide the chains length was significantly reduced; (5) during neap tide, the less intense vertical diffusion of nutrients, as well as the lower turbulence around the chains, intensified nutrient-depleted conditions and, thus, very large chains became disadvantageous. To explain this pattern, we suggest that size plasticity is an important ecological trait driving phytoplankton species competition. Although this plasticity behavior is well known from experiments in the laboratory, it has never been reported from observations in the field.
Published: 2014
Full Text: View/download PDF

29. Dynamique des matières en suspension minérales des eaux de surface de la Manche observée par satellite et modélisée numériquement

Author: Rivier, Aurélie, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Eau Mer et Fleuves (Cerema Direction Eau Mer et Fleuves), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Université de Bretagne occidentale - Brest, and Georges Chapalain
Subjects: Turbidité, English Channel, Télédétection, Tide, Houle, Marée, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Matière en suspension, Manche, Suspended particulate matter, Remote-sensing, Modelling, Turbidity, Sédiments, Satellite, Modélisation, Wave
Abstract: Study of mineral suspended particulate matter (SPM) is essential to understand ecosystem dynamics. SPM influences light penetration which is closely related to primary production and carries pollutants and nutrients within the water masses. This work aims to study near-surface mineral SPM dynamics in the English Channel using two complementary methods: remote-sensing by satellites and numerical modelling.Firstly, MODIS and MERIS satellite images processed by the IFREMER semi-analytical algorithm and describing non-algal SPM, are analysed to build three statistical models which are able to estimate near-surface SPM using simple variables, e.g., tidal coefficient, significant wave height and mean chlorophyll-a concentration. Secondly, the three-dimensional hydrosedimentary model ROMS (Regional Ocean Modeling System) is applied in the English Channel. It considers tidal forcing along open boundaries, wind stress at the sea-surface, wave-current interactions in the bottom boundary layer and realistic heterogeneous bottom sediments. Results of the more sophisticated statistical model is also used to impose SPM concentrations at open boundaries. Sensitivity tests on SPM boundary conditions show the importance of prescribing realistic sediment concentrations to improve the model predictions. Biological influences on mineral SPM are also tested using settling velocity and critical shear stress for erosion which vary with seasons.Both statistical and numerical models highlight and locate respective influences of tide, waves and biology on mineral SPM. Numerical predictions indicate that near-surface SPM is mainly composed of silts (>70%). Near-surface suspended silts come largely from seabed resuspension alongshore in the Eastern Channel and from the open boundaries of our limited-area coastal model at the West of Cotentin Peninsula and offshore. Near-surface SPM variations are investigated at semi-diurnal, neap-spring tidal cycle time scales and during a wave event. Finally, dynamics of sediments in the turbidity maximum zone around the Isle of Wight is examined depending on hydrodynamical conditions in order to distinguish the role played by advection and local erosion/settling processes in this area.; L'étude des matières en suspension (MES) minérales est essentielle pour comprendre le fonctionnement des écosystèmes en Manche : les MES influencent la pénétration de la lumière dans la colonne d'eau, paramètre clé pour la production biologique, et sont susceptibles de transporter des polluants et nutriments. Lors de ce travail, la dynamique des MES minérales de surface en Manche est étudiée à l'aide de deux méthodes complémentaires : l'observation par satellite et la modélisation numérique tridimensionnelle. Dans un premier temps, les images satellite MODIS et MERIS, traitées par l'algorithme semi-analytique développé par l'IFREMER et représentant les MES non-algales de surface, sont analysées afin d'élaborer trois modèles statistiques permettant d'estimer la MES de surface en fonction de variables basiques telles que le coefficient de marée, la hauteur significative des vagues et la concentration moyenne en chlorophylle-a. Dans un deuxième temps, le modèle hydrosédimentaire multiclasse tridimensionnel ROMS (Regional Ocean Modeling System) est implémenté en Manche. Il prend en considération le forçage par la marée aux frontières ouvertes, la contrainte exercée par le vent à la surface de la mer, l'interaction houle-courant en couche limite de fond et l’hétérogénéité spatiale réaliste du lit sédimentaire. Les résultats du modèle statistique le plus sophistiqué sont également utilisés pour forcer la concentration en MES aux frontières ouvertes du domaine de calcul. Des tests de sensibilité sur les conditions limites montrent l'importance de considérer de manière réaliste les sédiments entrant en Manche par les frontières ouvertes lors de la modélisation numérique. L'influence de la biologie sur les MES minérales est testée en utilisant une formulation de la vitesse de chute et de la contrainte critique d'érosion variant saisonnièrement.Grâce à ces deux outils associés, les influences respectives de la marée, de la houle et de la biologie sur les MES minérales sont mises en avant et localisées en Manche. Le modèle numérique prédit que les MES de surface sont composées principalement de silts (>70%). Les silts en suspension en surface proviennent majoritairement du lit sédimentaire près des côtes en Manche orientale et des frontières ouvertes du domaine de calcul à l'ouest de la presqu'île du Cotentin et au large en Manche centrale et orientale. Les variations des MES de surface sont ensuite étudiées aux échelles des cycles de marée semi-diurnes, vive-eau/morte-eau et autour d'un épisode de houles. Enfin, l'évolution de la concentration de sédiments dans la zone de forte turbidité autour de l'île de Wight peut être analysée suivant les conditions hydrodynamiques afin d'évaluer les rôles respectifs des processus locaux d'érosion/dépot et d'advection dans la génération de ces turbidités remarquables.
Published: 2013

30. Dynamique des matières en suspension minérales des eaux de surface de la Manche observée par satellite et modélisée numériquement

Author: Rivier, Aurélie, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Eau Mer et Fleuves (Cerema Direction Eau Mer et Fleuves), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Université de Bretagne occidentale - Brest, and Georges Chapalain
Subjects: Turbidité, Télédétection, télédétection, houle, satellite, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, wave, Remote-sensing, marée, Modelling, Turbidity, modelling, remote-sensing, Wave, modélisation, sédiments, English Channel, Tide, sediments, Houle, Marée, Matière en suspension, Manche, Suspended particulate matter, turbidity, Sédiments, Satellite, Modélisation, tide, turbidité
Abstract: Study of mineral suspended particulate matter (SPM) is essential to understand ecosystem dynamics. SPM influences light penetration which is closely related to primary production and carries pollutants and nutrients within the water masses. This work aims to study near-surface mineral SPM dynamics in the English Channel using two complementary methods: remote-sensing by satellites and numerical modelling. Firstly, MODIS and MERIS satellite images processed by the IFREMER semi-analytical algorithm and describing non-algal SPM, are analysed to build three statistical models which are able to estimate near-surface SPM using simple variables, e.g., tidal coefficient, significant wave height and mean chlorophyll-a concentration. Secondly, the three-dimensional hydrosedimentary model ROMS (Regional Ocean Modeling System) is applied in the English Channel. It considers tidal forcing along open boundaries, wind stress at the sea-surface, wave-current interactions in the bottom boundary layer and realistic heterogeneous bottom sediments. Results of the more sophisticated statistical model is also used to impose SPM concentrations at open boundaries. Sensitivity tests on SPM boundary conditions show the importance of prescribing realistic sediment concentrations to improve the model predictions. Biological influences on mineral SPM are also tested using settling velocity and critical shear stress for erosion which vary with seasons. Both statistical and numerical models highlight and locate respective influences of tide, waves and biology on mineral SPM. Numerical predictions indicate that near-surface SPM is mainly composed of silts (>70%). Near-surface suspended silts come largely from seabed resuspension alongshore in the Eastern Channel and from the open boundaries of our limited-area coastal model at the West of Cotentin Peninsula and offshore. Near-surface SPM variations are investigated at semi-diurnal, neap-spring tidal cycle time scales and during a wave event. Finally, dynamics of sediments in the turbidity maximum zone around the Isle of Wight is examined depending on hydrodynamical conditions in order to distinguish the role played by advection and local erosion/settling processes in this area. Keywords: Suspended particulate matter, satellite, remote-sensing, modelling, English Channel, sediments, turbidity, tide, wave, L'étude des matières en suspension (MES) minérales est essentielle pour comprendre le fonctionnement des écosystèmes en Manche : les MES influencent la pénétration de la lumière dans la colonne d'eau, paramètre clé pour la production biologique, et sont susceptibles de transporter des polluants et nutriments. Lors de ce travail, la dynamique des MES minérales de surface en Manche est étudiée à l'aide de deux méthodes complémentaires : l'observation par satellite et la modélisation numérique tridimensionnelle. Dans un premier temps, les images satellite MODIS et MERIS, traitées par l'algorithme semi-analytique développé par l'IFREMER et représentant les MES non-algales de surface, sont analysées afin d'élaborer trois modèles statistiques permettant d'estimer la MES de surface en fonction de variables basiques telles que le coefficient de marée, la hauteur significative des vagues et la concentration moyenne en chlorophylle-a. Dans un deuxième temps, le modèle hydrosédimentaire multiclasse tridimensionnel ROMS (Regional Ocean Modeling System) est implémenté en Manche. Il prend en considération le forçage par la marée aux frontières ouvertes, la contrainte exercée par le vent à la surface de la mer, l'interaction houle-courant en couche limite de fond et l’hétérogénéité spatiale réaliste du lit sédimentaire. Les résultats du modèle statistique le plus sophistiqué sont également utilisés pour forcer la concentration en MES aux frontières ouvertes du domaine de calcul. Des tests de sensibilité sur les conditions limites montrent l'importance de considérer de manière réaliste les sédiments entrant en Manche par les frontières ouvertes lors de la modélisation numérique. L'influence de la biologie sur les MES minérales est testée en utilisant une formulation de la vitesse de chute et de la contrainte critique d'érosion variant saisonnièrement. Grâce à ces deux outils associés, les influences respectives de la marée, de la houle et de la biologie sur les MES minérales sont mises en avant et localisées en Manche. Le modèle numérique prédit que les MES de surface sont composées principalement de silts (>70%). Les silts en suspension en surface proviennent majoritairement du lit sédimentaire près des côtes en Manche orientale et des frontières ouvertes du domaine de calcul à l'ouest de la presqu'île du Cotentin et au large en Manche centrale et orientale. Les variations des MES de surface sont ensuite étudiées aux échelles des cycles de marée semi-diurnes, vive-eau/morte-eau et autour d'un épisode de houles. Enfin, l'évolution de la concentration de sédiments dans la zone de forte turbidité autour de l'île de Wight peut être analysée suivant les conditions hydrodynamiques afin d'évaluer les rôles respectifs des processus locaux d'érosion/dépot et d'advection dans la génération de ces turbidités remarquables. Mots-clés : Matière en suspension, télédétection, satellite, modélisation, Manche, sédiments, turbidité, marée, houle
Published: 2013

31. Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron oyster farming bay: Insights from stable isotopes and microalgae ecology

Author: Pascale Malestroit, Nathalie Malet, Mireille Ryckaert, Pierre-Guy Sauriau, Gaël Guillou, Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés (CRELA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), LER/LR, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Département de la Charente-Maritime, France, CNRS, and IFREMER
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, microphytobenthos, Marennes-Oléron Bay, Oyster farming, Aquatic Science, Oceanography, 01 natural sciences, heatwave, Phytoplankton, 14. Life underwater, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Detritus, biology, Ecology, Terrigenous sediment, 010604 marine biology & hydrobiology, Marennes Oléron Bay, Pelagic zone, Estuary, biology.organism_classification, Zostera noltii, suspended particulate organic matter, 13. Climate action, Benthic zone, phytoplankton, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, mudflat
Abstract: The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron oyster farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ13C = −250/00 to −230/00) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ13C = − 220/00 to −190/00); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ13C = −21 to −230/00) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003the warmest summer on record in southern France and EuropeSPOM was particularly enriched for 13C, with δ13C values ranging from −140/00 to −120/00. Pulses in δ13C values, indicative of 13C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oléron Bay may lead to differences in the quality of the trophic environment available for reared oysters.
Published: 2008
Full Text: View/download PDF

32. Cophylogeny of the anther smut fungi and their caryophyllaceous hosts: Prevalence of host shifts and importance of delimiting parasite species for inferring cospeciation

Author: Florian Jabbour, Guislaine Refrégier, Mickael Le Gac, Jacqui A. Shykoff, Alex Widmer, Tatiana Giraud, Michael E. Hood, Roxana Yockteng, Université Paris-Sud - Paris 11 (UP11), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Systématique, Evolution, Biodiversité (ISYEB ), Muséum national d'Histoire naturelle (MNHN)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institute of Integrative Biology (IBZ), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Génétique et Écologie Évolutives, Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Department of Biology, Amherst College, AgroParisTech, Université Paris Saclay (COmUE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Caryophyllaceae, Generalist and specialist species, 01 natural sciences, Host Species, ddc:630, Phylogeny, ComputingMilieux_MISCELLANEOUS, 0303 health sciences, biology, Phylogenetic tree, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], food and beverages, Agriculture, Biodiversity, Life sciences, 3. Good health, ddc:580, Host-Pathogen Interactions, Research Article, Fungal Tree, Evolution, Genetic Speciation, Parasite Species, 010603 evolutionary biology, Intraspecific competition, 03 medical and health sciences, Parasite Tree, Species Specificity, Phylogenetics, ddc:570, QH359-425, Ecosystem, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, Host (biology), Basidiomycota, Host Shift, Bayes Theorem, 15. Life on land, biology.organism_classification, Cladogenesis, Evolutionary biology, Botanical sciences, Microbotryum
Abstract: Background Using phylogenetic approaches, the expectation that parallel cladogenesis should occur between parasites and hosts has been validated in some studies, but most others provided evidence for frequent host shifts. Here we examine the evolutionary history of the association between Microbotryum fungi that cause anther smut disease and their Caryophyllaceous hosts. We investigated the congruence between host and parasite phylogenies, inferred cospeciation events and host shifts, and assessed whether geography or plant ecology could have facilitated the putative host shifts identified. For cophylogeny analyses on microorganisms, parasite strains isolated from different host species are generally considered to represent independent evolutionary lineages, often without checking whether some strains actually belong to the same generalist species. Such an approach may mistake intraspecific nodes for speciation events and thus bias the results of cophylogeny analyses if generalist species are found on closely related hosts. A second aim of this study was therefore to evaluate the impact of species delimitation on the inferences of cospeciation. Results We inferred a multiple gene phylogeny of anther smut strains from 21 host plants from several geographic origins, complementing a previous study on the delimitation of fungal species and their host specificities. We also inferred a multi-gene phylogeny of their host plants, and the two phylogenies were compared. A significant level of cospeciation was found when each host species was considered to harbour a specific parasite strain, i.e. when generalist parasite species were not recognized as such. This approach overestimated the frequency of cocladogenesis because individual parasite species capable of infecting multiple host species (i.e. generalists) were found on closely related hosts. When generalist parasite species were appropriately delimited and only a single representative of each species was retained, cospeciation events were not more frequent than expected under a random distribution, and many host shifts were inferred. Current geographic distributions of host species seemed to be of little relevance for understanding the putative historical host shifts, because most fungal species had overlapping geographic ranges. We did detect some ecological similarities, including shared pollinators and habitat types, between host species that were diseased by closely related anther smut species. Overall, genetic similarity underlying the host-parasite interactions appeared to have the most important influence on specialization and host-shifts: generalist multi-host parasite species were found on closely related plant species, and related species in the Microbotryum phylogeny were associated with members of the same host clade. Conclusion We showed here that Microbotryum species have evolved through frequent host shifts to moderately distant hosts, and we show further that accurate delimitation of parasite species is essential for interpreting cophylogeny studies., BMC Evolutionary Biology, 8, ISSN:1471-2148
Published: 2008
Full Text: View/download PDF

33. Speciation in fungi

Author: Guislaine Refrégier, Mickael Le Gac, Michael E. Hood, Damien M. de Vienne, Tatiana Giraud, Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Institut de génétique et microbiologie [Orsay] (IGM), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Evolutionary Biology and Ecology of Algae (EBEA), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS), Bioinformatique, phylogénie et génomique évolutive (BPGE), Département PEGASE [LBBE] (PEGASE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Department of Biology, Amherst College, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), AgroParisTech, Université Paris Saclay (COmUE), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Universidad Austral de Chile-Centre National de la Recherche Scientifique (CNRS)-Pontificia Universidad Católica de Chile (UC)
Subjects: 0106 biological sciences, Heteropatric speciation, Genetic Speciation, Allopatric speciation, Biology, Parapatric speciation, 010603 evolutionary biology, 01 natural sciences, Microbiology, Ecological speciation, Epigenesis, Genetic, Evolution, Molecular, 03 medical and health sciences, Species Specificity, Genetic algorithm, Genetics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0303 health sciences, Ecology, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Fungi, Incipient speciation, Evolutionary biology, Sympatric speciation, Host-Pathogen Interactions, Chromosomes, Fungal
Abstract: In this review on fungal speciation, we first contrast the issues of species definition and species criteria and show that by distinguishing the two concepts the approaches to studying the speciation can be clarified. We then review recent developments in the understanding of modes of speciation in fungi. Allopatric speciation raises no theoretical problem and numerous fungal examples exist from nature. We explain the theoretical difficulties raised by sympatric speciation, review the most recent models, and provide some natural examples consistent with speciation in sympatry. We describe the nature of prezygotic and postzygotic reproductive isolation in fungi and examine their evolution as functions of temporal and of the geographical distributions. We then review the theory and evidence for roles of cospeciation, host shifts, hybridization, karyotypic rearrangement, and epigenetic mechanisms in fungal speciation. Finally, we review the available data on the genetics of speciation in fungi and address the issue of speciation in asexual species.
Published: 2008
Full Text: View/download PDF

34. Evolution of reproductive isolation within a parasitic fungal species complex

Author: Michael E. Hood, Mickael Le Gac, Tatiana Giraud, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Department of Biology, Amherst College, AgroParisTech, Université Paris Saclay (COmUE), Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)
Subjects: 0106 biological sciences, Hyphal growth, Species complex, 010603 evolutionary biology, 01 natural sciences, Models, Biological, 03 medical and health sciences, Genetics, Mating, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0303 health sciences, biology, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Basidiomycota, Reproduction, Assortative mating, Microbotryum violaceum, Reproductive isolation, biology.organism_classification, Biological Evolution, Genetic divergence, Evolutionary biology, General Agricultural and Biological Sciences, Microbotryum
Abstract: Despite important advances in the last few years, the evolution of reproductive isolation (RI) remains an unresolved and critical gap in our understanding of speciation processes. In this study, we investigated the evolution of RI among species of the parasitic fungal species complex Microbotryum violaceum, which is responsible for anther smut disease of the Caryophyllaceae. We found no evidence for significant positive assortative mating by M. violaceum even over substantial degrees of genetic divergence, suggesting a lack of prezygotic isolation. In contrast, postzygotic isolation increased with the genetic distance between mating partners when measured as hyphal growth. Total RI, measured as the ability of the pathogen to infect and produce a diploid progeny in the host plant, was significantly and positively correlated with genetic distance, remaining below complete isolation for most of the species pairs. The results of this study, the first one on the time course of speciation in a fungus, are therefore consistent with previous works showing that RI generally evolves gradually with genetic distance, and thus presumably with time. Interestingly, prezygotic RI due to gamete recognition did not increase with genetic distance, in contrast to the pattern found in plants and animals.
Published: 2007
Full Text: View/download PDF

35. Phylogenetic evidence of host-specific cryptic species in the anther smut fungus

Author: Mickael Le Gac, Elisabeth Fournier, Tatiana Giraud, Michael E. Hood, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Department of Biology, Amherst College, Renault DREAM, RENAULT, AgroParisTech, Université Paris Saclay (COmUE), Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)
Subjects: 0106 biological sciences, Sympatry, Gene Flow, Species complex, Nuclear gene, Genetic Speciation, Molecular Sequence Data, Adaptation, Biological, Introgression, Caryophyllaceae, 010603 evolutionary biology, 01 natural sciences, Gene flow, 03 medical and health sciences, Peptide Elongation Factor 1, Species Specificity, Tubulin, SIBLING SPECIES, Botany, Genetics, Cluster Analysis, ADAPTATION, Symbiosis, SPECIALIZATION, Ecology, Evolution, Behavior and Systematics, Phylogeny, 030304 developmental biology, DNA Primers, 0303 health sciences, biology, Phylogenetic tree, Base Sequence, Geography, Models, Genetic, SYMPATRY, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], Basidiomycota, Microbotryum violaceum, Bayes Theorem, MULTIPLE GENE GENEALOGIES, Sequence Analysis, DNA, 15. Life on land, CRYPTIC SPECIES, biology.organism_classification, Evolutionary biology, USTILAGO VIOLACEA, General Agricultural and Biological Sciences, Microbotryum
Abstract: International audience; Cryptic structure of species complexes confounds an accurate accounting of biological diversity in natural systems. Also, cryptic sibling species often become specialized to different ecological conditions, for instance, with host specialization by cryptic parasite species. The fungus Microbotryum violaceum causes anther smut disease in plants of Caryophyllaceae, and the degree of specialization and gene flow between strains on different hosts have been controversial in the literature. We conducted molecular phylogenetic analyses on M. violaceum from 23 host species and different geographic origins using three single-copy nuclear genes (beta-tub, gamma-tub, and Ef1 alpha). Congruence between the phylogenies identified several lineages that evolved independently for a long time. The lineages had overlapping geographic ranges but were highly specialized on different hosts. These results thus suggest that M. violaceum is a complex of highly specialized sibling species. Two incongruencies between the individual gene phylogenies and one intragene recombination event were detected at basal nodes, suggesting ancient introgression events or speciation events via hybridizations. However, incongruencies and recombination were not detected among terminal branches, indicating that the potentials for cross-infection and experimental hybridization are often not sufficient to suggest that introgressions would likely persist in nature.
Published: 2007
Full Text: View/download PDF

36. Nutrient dynamics at the sediment-water interface in a Mediterranean lagoon (Thau, France): Influence of biodeposition by shellfish farming activities

Author: Valérie Mesnage, Jean-Robert Disnar, Sylvie Ogier, Yoann Copard, G. Bally, Karine Dedieu, Christophe Rabouille, Nathalie Lottier, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Programme National Environnement Côtier ((Ifremer, CNRS, IRD, CNES, Brgm, Cemagref) et une entreprise privée (Total), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Laboratoire de chimie physique et rayonnements (UMR E4) (LCPR), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: 0106 biological sciences, Mediterranean climate, Geologic Sediments, [SDE.MCG]Environmental Sciences/Global Changes, Carbohydrates, Aquaculture, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, Nutrient, Sediment–water interface, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Dissolved organic carbon, Mediterranean Sea, Organic matter, Seawater, Dissolved organic matter, 14. Life underwater, Neutral carbohydrate, 91.67.-y, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, chemistry.chemical_classification, Ecology, 010604 marine biology & hydrobiology, Life Sciences, Phosphorus, General Medicine, Nutrients, Sedimentation, Eutrophication, Pollution, Anoxic waters, 6. Clean water, Carbon, Quaternary Ammonium Compounds, Nutrient fluxes, chemistry, Sediment-water interface, Coastal waters, France, Environmental Monitoring, Hydrogen
Abstract: International audience; The Thau Lagoon, a French Mediterranean shallow lagoon, is a site where extensive shellfish farming occurs. The aim of the present work is to evaluate the role of this activity on nutrient exchange at the sediment-water interface in relation to organic matter (OM) sedimentation and degradation. Two stations inside (C5) and outside (C4) of the shellfish farming areas were sampled at three seasons. Porewater chemistry surveys and calculated diffusive fluxes were used to evaluate the trophic status of the Thau lagoon. Quantitative (Particulate Organic Carbon) as well as qualitative OM (Hydrogen Index, Carbohydrates) analyses were performed on sediments to assess OM characteristics. Results emphasized that surficial sediments at C5 are always more enriched in OM. Porewater nutrient concentrations are 10-20 times higher at C5 than at C4. In June 2003, the porewater profiles exhibit a sharp gradient at the bottom waters, indicating a hypereutrophic status, leading to an anoxic crisis.
Published: 2007
Full Text: View/download PDF

37. Spatial distribution of zooplankton size spectra on the French continental shelf of the Bay of Biscay during spring 2000 and 2001

Author: Francois Carlotti, Marc Sourisseau, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Océanographie Physique et Biogéochimique (LOPB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, Aquatic Science, Oceanography, Spatial distribution, 01 natural sciences, Zooplankton, Geochemistry and Petrology, Abundance (ecology), Earth and Planetary Sciences (miscellaneous), 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biomass (ecology), geography, geography.geographical_feature_category, Ecology, Continental shelf, 010604 marine biology & hydrobiology, Paleontology, Forestry, Plankton, [SDE.ES]Environmental Sciences/Environmental and Society, Geophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, [SDE]Environmental Sciences, Spatial ecology, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract: International audience; During two cruises in springtime (18 March to 13 April 2000 and 27 March to 4 June 2001), the whole French continental shelf of the Bay of Biscay was sampled to obtain an overview on the zooplankton community size structure. A laboratory optical plankton counter (OPC-1L) was used to process plankton net tow samples and estimate abundance, biovolume, and general characteristics of size spectra. In a second step, biomass estimates were extrapolated from size by using a conversion factor. Both biomass and abundance estimates show spatial patterns with a clear coastal-open sea gradient for both years. The coastal area was characterized by the highest biomasses and abundances per volume. A first analysis of the zooplankton community size spectra was made by using the slope of the normalized biomass size spectrum. Different spatial patterns of zooplankton size spectra were highlighted for spring 2000 and 2001. The highest slopes were found for the coastal zone, showing a large ratio of small organisms, although this was less marked in the springtime 2000. Stations characterized by high proportions of large organisms were located in majority in the north of the bay and at the shelf break. A second analysis using the size probability distributions of organisms revealed a nearly permanent nonlinearity of probability distributions. This implied the community structure was not in an equilibrium state during spring and this nonlinearity could be locally related to dominant species dynamics.
Published: 2006
Full Text: View/download PDF

38. Exchange and release processes Dialysis porewater sampler: a strategy for time equilibration optimisation p1-9 in Phosphates in sediments

Author: Bally, G., Mesnage, V., Verney, R., Clarisse, O., Dupont, Jean-Paul, Ouddane, B., Lafite, R., Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Analytique Marine, Université de Lille, Laboratoire de Chimie Analytique et Marine - UPRESA 8013 (ELICO), Université de Lille, Sciences et Technologies, Université des sciences et technologies, Equipe Chimie Analytique et Marine Laboratoire Géosystèmes, Avelin, Herve, Unité Dyneco, Laboratoire Pelagos, and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: [SDE] Environmental Sciences, [SDE]Environmental Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2005

39. Chemical characterization of porewaters in an intertidal mudflat of the Seine estuary : relationship to erosion-deposition cycles

Author: Olivier Clarisse, Robert Lafite, Valérie Mesnage, G. Bally, Julien Deloffre, Jean-Paul Dupont, Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Analytique Marine, Université de Lille, Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), and Avelin, Herve
Subjects: 0106 biological sciences, Geologic Sediments, Nitrogen, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, Deposition (geology), [SDU] Sciences of the Universe [physics], Rivers, Sediment–water interface, Dissolved organic carbon, Water Movements, Organic matter, 14. Life underwater, Organic Chemicals, Ecosystem, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, chemistry.chemical_classification, Total organic carbon, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Sediment, Estuary, Phosphorus, Mineralization (soil science), Pollution, 6. Clean water, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental science, France, Seasons, Porosity, Environmental Monitoring
Abstract: A seasonal field study was carried out in the Seine estuary to determine the chemistry of sediment porewaters using the 'peeper' technique and changes in the elevation of the mudflats using the 'Altus' technique. This approach allowed us to evaluate the release of nutrients and to link these releases to the sediment hydrodynamics. Our results show that nutrient and organic matter cycling in a Seine estuary mudflat exhibits a seasonal behaviour, which is mainly influenced by variations in hydrodynamics. Sediments, rich organic matter, were input during floods and they were mineralized during summer and autumn, releasing nutrients and dissolved organic carbon into the sediment porewaters. The nutrient release, including ammonium, is mainly linked to the mineralization of organic matter, while the release of phosphate is delayed. The delay could be the result of phosphate association with organic matter and/or its co-precipitation with calcium and iron.
Published: 2004

40. Assessing spatial and temporal variability of phytoplankton communities' composition in the Iroise Sea ecosystem (Brittany, France): A 3D modeling approach. Part 1: Biophysical control over plankton functional types succession and distribution

Author: Louis Marié, Marc Sourisseau, Laurent Memery, Christopher A. Edwards, Thomas Gorgues, Olivier Aumont, Mathilde Cadier, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), University of California [Santa Cruz] (UCSC), University of California, Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Water mass, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Mixed layer, growth, chibido, coastal waters, prochlorococcus, Biology, Aquatic Science, Tidal mixing front, Oceanography, thermal front, Seasonal cycle, 01 natural sciences, marine-phytoplankton, ushant tidal front, Biogeochemical modeling, Phytoplankton, Dominance (ecology), Ecosystem, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Iroise Sea, 0105 earth and related environmental sciences, atlantic-ocean, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, photosynthesis, Ecology, 010604 marine biology & hydrobiology, ACL, fungi, Niche differentiation, Plankton, 13. Climate action, Functional groups, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, light, cell-size
Abstract: Understanding the dynamic interplay between physical, biogeochemical and biological processes represents a key challenge in oceanography, particularly in shelf seas where complex hydrodynamics are likely to drive nutrient distribution and niche partitioning of phytoplankton communities. The Iroise Sea includes a tidal front called the 'Ushant Front' that undergoes a pronounced seasonal cycle, with a marked signal during the summer. These characteristics as well as relatively good observational sampling make it a region of choice to study processes impacting phytoplankton dynamics. This innovative modeling study employs a phytoplankton-diversity model, coupled to a regional circulation model to explore mechanisms that alter biogeography of phytoplankton in this highly dynamic environment. Phytoplankton assemblages are mainly influenced by the depth of the mixed layer on a seasonal time scale. Indeed, solar incident irradiance is a limiting resource for phototrophic growth and small phytoplankton cells are advantaged over larger cells. This phenomenon is particularly relevant when vertical mixing is intense, such as during winter and early spring. Relaxation of wind-induced mixing in April causes an improvement of irradiance experienced by cells across the whole study area. This leads, in late spring, to a competitive advantage of larger functional groups such as diatoms as long as the nutrient supply is sufficient. This dominance of large, fast-growing autotrophic cells is also maintained during summer in the productive tidally-mixed shelf waters. In the oligotrophic surface layer of the western part of the Iroise Sea, small cells coexist in a greater proportion with large, nutrient limited cells. The productive Ushant tidal front's region (1800 mgC.m -2 .d -1 between August and September) is also characterized by a high degree of coexistence between three functional groups (diatoms, micro/nano-flagellates and small eukaryotes/cyanobacteria). Consistent with previous studies, the biogeography of phytoplankton functional types at the Ushant front during summer displays an intermediate community composition between contrasted sub-regions on either side of the front. Strong mixing conditions within the frontal sub-region result in a short residence time of water masses, not allowing speciation or long term adaptation to occur. (C) 2016 The Authors. Published by Elsevier B.V.
Full Text: View/download PDF

41. Projet TOSCA OSYNICO : Optimisation et SYNergie des données In situ et COuleur de l'eau pour l’étude de la dynamique biogéochimique des eaux côtières

Author: Vincent Vantrepotte, Trung Kien Tran, Hubert Loisel, Cédric Jamet, Schmitt, François G., Sabine Schmitt, Nicolas Savoye, David Doxaran, Pierre Gernez, Francis Gohin, Matthieu Puigt, Franck Dufrenois, Jean-Louis Blin, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Université du Littoral Côte d'Opale (ULCO), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'Informatique Signal et Image de la Côte d'Opale (LISIC), Synergie MEr et Littoral (SMEL), Projet OSYNICO (financement CNES TOSCA), OSYNICO, Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN)-Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Unité Dyneco, Laboratoire Pelagos, and Dynamiques de l'Environnement Côtier (DYNECO)
Subjects: couplage in situ/satellite, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, télédétection couleur de l’eau
Abstract: National audience; La mise en place de plusieurs réseaux nationaux d’observation in situ (e.g. SOMLIT, REPHY, COAST-HF,..) ainsi que les récents développements méthodologiques en terme d’observation spatiale dite « couleur de l’eau » à l’échelle nationale permettent désormais de suivre la dynamique des eaux côtières françaises à de multiples échelles spatiales ou temporelles. L’exploitation de ces informations terrain ou satellite, généralement effectuée de manière indépendante, doit cependant faire face à différentes limitations propres aux observations in situ (e.g. faible emprise spatiale : données localisées et nombre de stations limité au sein d’un même site ou le long du littoral) ou aux données satellitaires (e.g. incertitudes sur les produits, fréquence d’acquisition, couverture temporelle réduite). Le projet OSYNICO (TOSCA/CNES) a été défini dans ce contexte et a pour objectif général de démontrer l’avantage de la complémentarité des observations in situ et satellite pour 1) décrire les évolutions à long terme (évolution des signaux moyens et des oscillations saisonnières) des caractéristiques biogéochimiques des eaux côtières françaises (de l’échelle locale à l’échelle synoptique) 2) d’apprécier l’impact des évènements climatiques extrêmes sur ces écosystèmes côtiers. Les bases de données et outils/métriques mis en place dans le cadre du projet pour la comparaison des dynamiques observées pour des variables clés (e.g. Chla, MES, POC) via les observations in situ et couleur seront présentés. Un focus sera effectué sur les premiers résultats obtenus aux échelles saisonnières et interannuelles.

42. The Seasonal and Inter-Annual Fluctuations of Plankton Abundance and Community Structure in a North Atlantic Marine Protected Area

Author: Benedetti, Fabio, Jalabert, Laëtitia, Sourisseau, Marc, Becker, Beatriz, Cailliau, Caroline, Desnos, Corinne, Elineau, Amanda, Irisson, Jean-Olivier, Lombard, Fabien, Picheral, Marc, Stemmann, Lars, Pouline, Patrick, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute of Biogeochemistry and Pollutant Dynamics [ETH Zürich] (IBP), Department of Environmental Systems Science [ETH Zürich] (D-USYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Unité Dyneco, Laboratoire Pelagos, Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Agence Française pour la Biodiversité (AFB), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), ANR-10-INBS-0002,EMBRC-France,CENTRE NATIONAL DE RESSOURCES BIOLOGIQUES MARINES(2010), European Project: 654410,H2020,H2020-INFRAIA-2014-2015,JERICO-NEXT(2015), Laboratoire d'Ecologie Pélagique (PELAGOS), Dynamiques des Écosystèmes Côtiers (DYNECO), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, size structure, temporal variability, ACL, fungi, plankton, Ocean Engineering, Aquatic Science, Oceanography, Life sciences, Plankton, Marine Protected Area, Seasonality, Copepod, MPA, ddc:570, community composition, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Iroise Sea, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Water Science and Technology
Abstract: International audience; Marine Protected Areas have become a major tool for the conservation of marine biodiversity and resources. Yet our understanding of their efficacy is often limited because it is measured for a few biological components, typically top predators or species of commercial interest. To achieve conservation targets, marine protected areas can benefit from ecosystem-based approaches. Within such an approach, documenting the variation of plankton indicators and their covariation with climate is crucial as plankton represent the base of the food webs. With this perspective, we sought to document the variations in the emerging properties of the plankton to better understand the dynamics of the pelagic fishes, mammals and seabirds that inhabit the region. For the first time, we analyze the temporal variations of the entire plankton community of one of the widest European protected areas, the Parc Naturel Marin de la Mer d’Iroise. We used data from several sampling transects carried out in the Iroise Sea from 2011 to 2015 to explore the seasonal and inter-annual variations of phytoplankton and mesozooplankton abundance, composition and size, as well as their covariation with abiotic variables, through multiple multivariate analyses. Overall, our observations are coherent with the plankton dynamics that have been observed in other regions of the North-East Atlantic. We found that both phytoplankton and zooplankton show consistent seasonal patterns in taxonomic composition and size structure but also display inter-annual variations. The spring bloom was associated with a higher contribution of large chain-forming diatoms compared to nanoflagellates, the latter dominating in fall and summer. Dinoflagellates show marked inter-annual variations in their relative contribution. The community composition of phytoplankton has a large impact on the mesozooplankton together with the distance to the coast. The size structure of the mesozooplankton community, examined through the ratio of small to large copepods, also displays marked seasonal patterns. We found that larger copepods (members of the Calanidae) are more abundant in spring than in summer and fall. We propose several hypotheses to explain the observed temporal patterns and we underline their importance for understanding the dynamics of other components of the food-web (such as sardines). Our study is a first step toward the inclusion of the planktonic compartment into the planning of the resources and diversity conservation within the Marine Protected Area.
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

Publisher

42 results on '"Unité Dyneco, Laboratoire Pelagos"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources