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1. Data quality control considerations in multivariate environmental monitoring: experience of the French coastal network SOMLIT

Author: Breton, Elsa, Savoye, Nicolas, Rimmelin-maury, Peggy, Sautour, Benoit, Goberville, Eric, Lheureux, Arnaud, Cariou, Thierry, Ferreira, Sophie, Agogué, Hélène, Alliouane, Samir, Aubert, Fabien, Aubin, Sébastien, Berthebaud, Eric, Blayac, Hadrien, Blondel, Lucie, Boulart, Cedric, Bozec, Yann, Bureau, Sarah, Caillo, Arnaud, Cauvin, Arnaud, Cazes, Jean-baptiste, Chasselin, Leo, Claquin, Pascal, Conan, Pascal, Cordier, Marie-ange, Costes, Laurence, Crec’hriou, Romain, Crispi, Olivier, Crouvoisier, Muriel, David, Valérie, Del Amo, Yolanda, De Lary, Hortense, Delebecq, Gaspard, Devesa, Jeremy, Domeau, Aurélien, Durozier, Maria, Emery, Claire, Feunteun, Eric, Fauchot, Juliette, Gentilhomme, Valérie, Geslin, Sandrine, Giraud, Mélanie, Grangeré, Karine, Grégori, Gerald, Grossteffan, Emilie, Gueux, Aurore, Guillaudeau, Julien, Guillou, Gael, Harrewyn, Manon, Jolly, Orianne, Jude-lemeilleur, Florence, Labatut, Paul, Labourdette, Nathalie, Lachaussée, Nicolas, Lafont, Michel, Lagadec, Veronique, Lambert, Christophe, Lamoureux, Jezebel, Lanceleur, Laurent, Lebreton, Benoit, Lecuyer, Eric, Lemeille, David, Leredde, Yann, Leroux, Cédric, Leynaert, Aude, L’helguen, Stéphane, Liénart, Camilla, Macé, Eric, Maria, Eric, Marie, Barbara, Marie, Dominique, Mas, Sébastien, Mendes, Fabrice, Mornet, Line, Mostajir, Behzad, Mousseau, Laure, Nowaczyk, Antoine, Nunige, Sandra, Parra, René, Paulin, Thomas, Pecqueur, David, Petit, Franck, Pineau, Philippe, Raimbault, Patrick, Rigaut-jalabert, Fabienne, Salmeron, Christophe, Salter, Ian, Sauriau, Pierre-guy, Seuront, Laurent, Sultan, Emmanuelle, Valdès, Rémi, Vantrepotte, Vincent, Vidussi, Francesca, Voron, Florian, Vuillemin, Renaud, Zudaire, Laurent., Garcia, Nicole, 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 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), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), 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), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-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), ESEO-GSII (GSII), ESEO-Tech, Université Bretagne Loire (UBL)-École supérieure d'électronique de l'ouest [Angers] (ESEO)-Université Bretagne Loire (UBL)-École supérieure d'électronique de l'ouest [Angers] (ESEO), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Université de Montpellier (UM), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Centre pour l'Aquaculture, la Pêche et l'Environnement (CAPENA), Centre de recherches en environnement côtier (CREC), Normandie Université (NU)-Normandie Université (NU), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de la Mer de Villefranche (IMEV), Groupement d'intérêt public pour la réhabilitation de l'étang de Berre (GIPREB), GIPREB, Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Normandie Université (NU), 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), UMS 3113, Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Banyuls (OOB), 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), Pluridisciplinarité au service de l’observation et de la recherche en environnement et astronomie (UMS POREA), Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Department of Marine Resources and Energy, Tokyo University of Marine Science and Technology (TUMSAT), Rhodes University, Grahamstown, Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), OSU Stations marines (STAMAR), and CNRS-INSU, SNO SOMLIT, French National Fleet (Flotte Océanographique Française, FOF)
Subjects: data quality control, inter-laboratory comparison exercises, Global and Planetary Change, [STAT.AP]Statistics [stat]/Applications [stat.AP], [SDE.IE]Environmental Sciences/Environmental Engineering, measurement uncertainty, environmental monitoring network, Ocean Engineering, analyst performance, Aquatic Science, Oceanography, multivariate dataset, Water Science and Technology
Abstract: IntroductionWhile crucial to ensuring the production of accurate and high-quality data—and to avoid erroneous conclusions—data quality control (QC) in environmental monitoring datasets is still poorly documented.MethodsWith a focus on annual inter-laboratory comparison (ILC) exercises performed in the context of the French coastal monitoring SOMLIT network, we share here a pragmatic approach to QC, which allows the calculation of systematic and random errors, measurement uncertainty, and individual performance. After an overview of the different QC actions applied to fulfill requirements for quality and competence, we report equipment, accommodation, design of the ILC exercises, and statistical methodology specially adapted to small environmental networks (Results, Discussion, ConclusionThe examination of the temporal variations (2001–2021) in the repeatability, reproducibility, and trueness of the SOMLIT network over time confirms the essential role of ILC exercises as a tool for the continuous improvement of data quality in environmental monitoring datasets.
Published: 2023

2. Impact of anoxia and oyster mortality on nutrient and microbial planktonic components: A mesocosm study

Author: Julie Le Ray, Béatrice Bec, Annie Fiandrino, Franck Lagarde, Nicolas Cimiterra, Patrick Raimbault, Cécile Roques, Sylvain Rigaud, Julie Régis, Behzad Mostajir, Sébastien Mas, Marion Richard, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), 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), Détection, évaluation, gestion des risques CHROniques et éMErgents (CHROME) / Université de Nîmes (CHROME), Université de Nîmes (UNIMES), Centre d'Ecologie marine expérimentale (MEDIMEER), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Oxygen, Anoxia, Microbial loop, [SDE.MCG]Environmental Sciences/Global Changes, Phytoplankton, Community shift, Aquatic Science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; The Thau lagoon is a Mediterranean coastal lagoon used for shellfish farming. It is periodically affected by anoxia events that trigger oyster mortality. To investigate the effects of an anoxia event focussed on nutrient dynamics and the responses of the microbial planktonic communities a 13-day in situ experiment was performed in September 2020. Transparent mesocosms (270 L) were placed at a depth of 4 m, inserted in the sediment, and kept closed throughout the experiment. The experiment comprised three treatments: i) Natural environment (N), i.e. in the natural water outside the mesocosms containing a rope of 30 oysters (Crassostrea gigas), ii) Control mesocosm (C) filled with natural water with no oysters, and iii) Oyster mesocosm (O) filled with natural water containing a rope of 30 oysters. Oyster respiration in the oyster mesocosm depleted oxygen after 54 h. All the oysters from O mesocosm were dead after nine days and decomposition of their flesh combined with releases from the water-sediment interface increased dissolved inorganic nitrogen (dominated by ammonium), phosphates, and ∑H2S up to 390, 17 and 295 μmol·L−1, respectively. Phytoplankton biomass consequently increased by 20 (11.8 μg chlal −1) and abundance by 4.5 (186 × 106 cells·L1) dominated largely by green algae \textless5 μm. During the oyster mortality period (day 6 to day 9) high abundances of heterotrophic flagellates and large ciliate specimens were observed. This shift in the community towards small phytoplankton favours the microbial loop and is detrimental to shellfish farming. In a context of global warming in which the risk of anoxia is higher, the results of the present investigation demonstrate that anoxia triggers shellfish mortality and that the change in the plankton community disrupts the normal functioning of the ecosystem, causing serious financial losses. In this context, it is crucial to predict possible hypoxia and anoxia events using high frequency measurements of dissolved oxygen, by avoiding using shallow zones for oyster production and by reducing shellfish stocks, or by mechanically lifting the oysters out of the water during the night to reduce oxygen respiration in the ecosystem.
Published: 2023

3. Brownification reduces oxygen gross primary production and community respiration and changes the phytoplankton community composition: An in situ mesocosm experiment with high‐frequency sensor measurements in a North Atlantic bay

Author: Tanguy Soulié, Herwig Stibor, Sébastien Mas, Benjamin Braun, Johanna Knechtel, Jens C. Nejstgaard, Ulrich Sommer, Francesca Vidussi, Behzad Mostajir, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Ludwig-Maximilians-Universität München (LMU), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), and Helmholtz Centre for Ocean Research [Kiel] (GEOMAR)
Subjects: Marine-phytoplankton, Light, Matter, [SDE.MCG]Environmental Sciences/Global Changes, fungi, Water, Aquatic Science, Oceanography, Planktonic food-web, Lakes, Dissolved organic-carbon, Metabolism, 13. Climate action, Pigment ratios, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Nutrient
Abstract: WOS:000753551000001; International audience; In recent decades, the increase in terrestrial inputs to freshwater and coastal ecosystems, especially occurring at northern latitudes, has led to a process of water color darkening known as "brownification." To assess how brownification affects plankton community composition and functioning in northern coastal areas, an in situ mesocosm experiment using a highly colored humic substance to simulate a brownification event was performed in a North Atlantic bay (Hopavagen, Norway) in August 2019. Manual sampling for analyses of nutrient concentrations, phytoplankton pigments and zooplankton abundances was combined with high-frequency (every 15 min) monitoring of key environmental variables to investigate the response of the plankton community in terms of oxygen metabolism and community composition. In response to brownification, the oxygen gross primary production (GPP) and community respiration (R) slowed down significantly, by almost one-third. However, GPP and R both decreased to the same extent; thus, the oxygen metabolic balance was not affected. Moreover, the chlorophyll-a concentration significantly decreased under brownification, by 9% on average, and the chemotaxonomic pigment composition of the phytoplankton changed, indicating their acclimation to the reduced light availability. In addition, brownification seemed to favor appendicularians, the dominant mesozooplankton group in the mesocosms, which potentially contributed to lowering the phytoplankton biomass. In conclusion, the results of this in situ mesocosm experiment suggest that brownification could induce significant changes in phytoplankton and zooplankton community composition and significantly alter the overall oxygen metabolism of plankton communities in a northern Atlantic bay.
Published: 2022

4. Metabolic responses of plankton to warming during different productive seasons in coastal Mediterranean waters revealed by in situ mesocosm experiments

Author: Tanguy Soulié, Francesca Vidussi, Justine Courboulès, Sébastien Mas, Behzad Mostajir, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Centre d'Ecologie marine expérimentale (MEDIMEER), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Diatoms, Oxygen, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Multidisciplinary, Chlorophyll A, fungi, Phytoplankton, Seasons, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, Plankton, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: The response of coastal lagoon plankton communities to warming was studied during two in situ mesocosm experiments in spring and fall of 2018 in the Mediterranean. Phytoplankton biomass, gross primary production (GPP), community respiration (R), phytoplankton growth (µ), and loss (l) rates were estimated using high-frequency chlorophyll-a fluorescence and dissolved oxygen sensors, and daily sampling was used to evaluate the nutrient status and phytoplankton pigment functional groups. Warming strongly depressed the dominant phytoplankton functional groups, mainly the prymnesiophytes, diatoms (spring), and green flagellates (fall). It favored minor groups such as the dinoflagellates (spring) and diatoms (fall). In spring, warming depressed GPP and R by half; however, µ (+ 18%) and l (+ 37%) were enhanced. In contrast, both GPP and µ were enhanced by 21% and 28%, respectively, in fall, and no effects were observed for R and l. Warming strongly decreased phytoplankton biomass and oxygen production in spring, and enhanced them, to a lesser extent, in fall. This led to an overall loss of production over both seasons. This study improves understanding of the contrasting effects of warming during two productive seasons, which depend on plankton community composition and interactions between components and environmental conditions.
Published: 2022

5. Functional Stability of a Coastal Mediterranean Plankton Community During an Experimental Marine Heatwave

Author: Tanguy Soulié, Francesca Vidussi, Sébastien Mas, Behzad Mostajir, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Centre d'Ecologie marine expérimentale (MEDIMEER), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
Subjects: phytoplankton growth, Science, Ocean Engineering, marine heatwave, Aquatic Science, QH1-199.5, acclimation, plankton metabolism, Oceanography, resistance, recovery, ultraviolet-b radiation, high-frequency measurements, bacterial, 14. Life underwater, increases, resilience, in situ mesocosms, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Water Science and Technology, Global and Planetary Change, abundance, exchange, General. Including nature conservation, geographical distribution, temperature, 13. Climate action, metabolic balance, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, respiration
Abstract: As heatwaves are expected to increase in frequency and intensity in the Mediterranean Sea due to global warming, we conducted an in situ mesocosm experiment for 20 days during the late spring and early summer of 2019 in a coastal Mediterranean lagoon to investigate the effects of heatwaves on the composition and function of coastal plankton communities. A heatwave was simulated by elevating the water temperature of three mesocosms to +3°C while three control mesocosms had natural lagoon water temperature, for 10 days. Further, the heating procedure was halted for 10 days to study the resilience and recovery of the system. Automated high frequency monitoring of dissolved oxygen concentration and saturation, chlorophyll-a fluorescence, photosynthetic active radiation, salinity, and water temperature was completed with manual sampling for nutrient and phytoplankton pigment analyses. High-frequency data were used to estimate different functional processes: gross primary production (GPP), community respiration (R), and phytoplankton growth (μ), and loss (l) rates. Ecosystem stability was assessed by calculating resistance, resilience, recovery, and temporal stability in terms of the key functions (GPP, R, μ, and l). Meanwhile, the composition of phytoplankton functional types (PFT) was assessed through chemotaxonomic pigment composition. During the heatwave, GPP, R, μ, and l increased by 31, 49, 16, and 21%, respectively, compared to the control treatment. These positive effects persisted several days after the offset of the heatwave, resulting in low resilience in these key functions. However, GPP and R recovered almost completely at the end of the experiment, suggesting that the effect of the heatwave on these two rates was reversible. The heatwave also affected the PFT composition, as diatoms, prymnesiophytes, and cyanobacteria were favored, whereas dinoflagellates were negatively affected. By highlighting important effects of a simulated marine heatwave on the metabolism and functioning of a coastal Mediterranean plankton community, this study points out the importance to extend this type of experiments to different sites and conditions to improve our understanding of the impacts of this climate-change related stressor that will grow in frequency and intensity in the future.
Published: 2022

6. Le réchauffement désavantage le phytoplancton au profit des bactéries pendant une efflorescence printanière dans la lagune de Thau en Méditerranée

Author: Justine Courboulès, Behzad Mostajir, Thomas Trombetta, Sébastien Mas, Francesca Vidussi, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Centre d'Ecologie marine expérimentale (MEDIMEER), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Global and Planetary Change, warming, biomass transfer, Ocean Engineering, grazing mortality rate, Aquatic Science, Oceanography, in situ mesocosm, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, biomass production, phytoplankton, growth rate, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, heterotrophic bacteria, Water Science and Technology
Abstract: To assess the response of a natural plankton community to the future scenario of a warming of +3°C predicted for coastal Mediterranean regions, an in situ mesocosm experiment was carried out over 19 days in a Mediterranean coastal lagoon in 2018. During this experiment, a phytoplankton bloom occurred and the abundances of several cytometric groups of phytoplankton (cyanobacteria, picophytoplankton and nanophytoplankton) and bacteria (low- and high-nucleic acid bacteria), as well as their growth and grazing mortality rates and their carbon biomass, were studied over the course of the experiment. Experimental warming led to a significant reduction of 47% of the phytoplankton biomass in average, based on Chl-a concentrations. This reduction was also observed for nanophytoplankton abundances during the whole experiment and for eukaryotic picophytoplankton only during the bloom period. This result coincided with a significant decrease in orthophosphate concentrations under warming during the prebloom and bloom periods simultaneous to an increase in bacterial abundances. At the same time, the higher growth rates of bacteria and the lower ones of phytoplankton observed at the beginning of the bloom could suggest that competition between phytoplankton and bacteria for orthophosphate might have contributed to the phytoplankton biomass decrease under warming. In addition, higher grazing mortality rates of phytoplankton groups under warming, notably nanophytoplankton at the end of the bloom and in postbloom (by 59 to 626%), as well as eukaryotic picophytoplankton over the course of the experiment (by 58 to 255%) could also have contributed to the lower phytoplankton biomass under warming. Based on these results, estimations of average phytoplankton carbon biomass production and transfer showed reductions of 42 and 45%, respectively, under warming, whereas those of bacteria were enhanced by 13 and 8%, respectively. These results indicated that warming induced a shift at the base of the microbial food web, going toward a more bacteria-based system. This suggested that under future warming scenarios, the microbial food web could become less productive and could negatively affect the functioning of the whole food web in coastal waters.
Published: 2022

7. Co-occurrence networks reveal the central role of temperature in structuring the plankton community of the Thau Lagoon

Author: Behzad Mostajir, Francesca Vidussi, Cécile Roques, Sébastien Mas, Thomas Trombetta, Marco Scotti, 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), 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), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), ANR-14-CE02-0018,Photo-Phyto,Effets du réchauffement climatique sur le déclenchement des blooms phytoplanctoniques marins : photoperiodisme, composition et adaptation(2014), and 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)
Subjects: 0106 biological sciences, Mediterranean climate, Science, Ecological succession, 01 natural sciences, Article, 03 medical and health sciences, Phytoplankton, 14. Life underwater, 030304 developmental biology, Trophic level, 0303 health sciences, Multidisciplinary, Ecology, 010604 marine biology & hydrobiology, fungi, Sediment, 15. Life on land, Plankton, Food web, Environmental sciences, Ocean sciences, Oceanography, 13. Climate action, Benthic zone, [SDE]Environmental Sciences, Medicine, Environmental science, Hydrology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; To identify the environmental factors that drive plankton community composition and structure in coastal waters, a shallow northwestern Mediterranean lagoon was monitored from winter to spring in two contrasting years. The campaign was based on high-frequency recordings of hydrological and meteorological parameters and weekly samplings of nutrients and the plankton community. The collected data allowed the construction of correlation networks, which revealed that water temperature was the most important factor governing community composition, structure and succession at different trophic levels, suggesting its ubiquitous food web control. Temperature favoured phytoplanktonic flagellates (Cryptophyceae, Chrysophyceae, and Chlorophyceae) and ciliates during winter and early spring. In contrast, it favoured Bacillariophyceae, dinoflagellates, phytoplankton < 6 µm and aloricate Choreotrichida during spring. The secondary factors were light, which influenced phytoplankton, and wind, which may regulate turbidity and the nutrient supply from land or sediment, thus affecting benthic species such as Nitzschia sp. and Uronema sp. or salinity-tolerant species such as Prorocentrum sp. The central role of temperature in structuring the co-occurrence network suggests that future global warming could deeply modify plankton communities in shallow coastal zones, affecting whole-food web functioning. Environmental forcing factors play a central role in driving plankton community composition and dynamics in marine and freshwater ecosystems. At a global scale, along latitudinal gradients, species distribution and community composition depend on abiotic conditions, such as temperature, light, and nutrients 1. On the other hand, at the local level, food web structure is more affected by biotic processes such as predation, competition, population growth and behaviour 2 , which are constrained by environmental conditions. However, in highly dynamic systems subject to intense environmental stressors, physico-chemical forcing factors may play a predominant role in shaping communities 3,4. Furthermore, the plankton community's response to environmental forcing factors in these systems is challenging to determine, as these factors can be influenced by various elements and are often linked together 5. For example, alongshore wind in coastal ecosystems triggers deep, cool and nutrient-rich water upwelling, thus influencing plankton communities 6,7. Consequently, the conjunction of wind direction and speed, column mixing, water temperature and nutrient concentration changes explains the plankton response during these events. Therefore, it is essential to study multiple environmental parameters together in particularly highly dynamic systems, as they can be tightly linked together. Shallow coastal waters, including coastal lagoons, estuaries, seagrass beds, and coral reefs, are highly dynamic and often exposed to extreme environmental events. Community composition and structure in these zones are driven by environmental forcing factors, mainly because the zones occupy the interface between land and sea 8. These factors influence plankton communities directly or indirectly. For instance, river runoff transports nutrients and terrigenous organic matter, influences water turbidity, and modulates phytoplankton and bacterial production 9,10. Seawater currents or tides recirculate nutrients, which provide critical elements for the food web and enrich local communities of offshore organisms 11-13. These water inputs and precipitation induce significant salinity variations that affect the plankton community 14,15. Moreover, the shallow depth of these coastal waters
Published: 2021

8. Silicate marine electrochemical sensor

Author: B. Jugeau, S. Mas, D. Chen Legrand, Arnaud David, Carole Barus, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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), Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), 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), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), NKE instrumentation, ANR-17-MART-0003,OCEANSensor,Development and metrological improvements of marine chemical sensors(2017), 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), 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), and European Project: 728053-MarTERA,OCEANSensor
Subjects: Materials science, Seawater deployment, Analytical chemistry, Artificial seawater, 02 engineering and technology, 010402 general chemistry, Intercomparison with colorimetry, 01 natural sciences, Reagentless electrochemical detection, Matrix (chemical analysis), chemistry.chemical_compound, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Validation with CRM, Materials Chemistry, Calibration, 14. Life underwater, Electrical and Electronic Engineering, Instrumentation, Detection limit, [SDE.IE]Environmental Sciences/Environmental Engineering, Metals and Alloys, Repeatability, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Silicate, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Electrochemical gas sensor, Certified reference materials, chemistry, 13. Climate action, 0210 nano-technology, In situ silicate sensor
Abstract: International audience; An autonomous electrochemical sensor suitable for in situ silicate detection and monitoring in marine environments, is presented without any use of liquid reagent. This paper shows silicate sensor characteristics and figures of merit using optimized chemical and electrochemical parameters. Under controlled laboratory conditions in a 40 L tank, good calibration between 1.63 and 132.8 μmol L − 1 was obtained. The limit of detection and the limit of quantification obtained are respectively LOD = 0.32 μmol L − 1 and LOQ = 1.08 μmol L − 1. No bias was found while analysing Certified Reference Material (CRM) solutions i.e. natural seawaters samples with different salinities and nutrients compositions. Repeatability test showed very good reproducibility of the measurement with low overall uncertainty, cumulating systematic error and reproducibility error, of 2.4 %. Accuracies obtained with the Silicate sensor are higher than 97.4 %, 95.3 % for the smallest concentration tested, under LOQ. Spike and recovery tests were conducted with two different CRM concentrations and showed 97.9-100.1 % recovery, indicating no matrix influence in the determination of silicate concentration using electrochemical sensor and its calibration process (realised with artificial seawater solutions). In situ deployment of silicate electrochemical sensor was realized in the Thau lagoon (Mediterranean Sea) at 1.6 m depth. A good agreement between the results obtained with the sensor compared to reference colorimetric measurements made at the Marine Station of Sète (France) validates sensor's performances.
Published: 2021

9. Changes in planktonic microbial components in interaction with juvenile oysters during a mortality episode in the Thau lagoon (France)

Author: Behzad Mostajir, Marion Richard, Charles Vanhuysse, Serge Mortreux, Béatrice Bec, Valerie Derolez, Jocelyne Oheix, Jean Luc Rolland, Patrick Le Gall, Vincent Ouisse, Sébastien Mas, Franck Lagarde, David Parin, Annie Fiandrino, Myriam D. Callier, Gregory Messiaen, Camila Chantalat, Martine Fortune, E. Hatey, Anaïs Degut, Dominique Munaron, Emmanuelle Roque D'Orbcastel, Laboratoire d'Informatique Médicale et Ingénierie des Connaissances en e-Santé (LIMICS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris 13 (UP13), 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), Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Environnement Ressources (LER-LR), 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), Interactions Hôtes-Pathogènes-Environnements (IHPE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Perpignan Via Domitia (UPVD), Institut Français de Recherche pour l'Exploitation de la Mer, Station expérimentale de Palavas les Flots, Laboratoire Laboratoire Environnement Ressources Morbihan Pays de Loire (LER/MPL), Université Paris 13 (UP13)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), 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 Environnement Ressources Languedoc Roussillon (LERLR), LITTORAL (LITTORAL), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), and Laboratoire Environnement Ressources Morbihan Pays de Loire (LERMPL)
Subjects: Spat, Oyster, animal structures, [SDV]Life Sciences [q-bio], Zoology, Aquatic Science, 03 medical and health sciences, Heterotrophic flagellates, Aquaculture, biology.animal, Juvenile, 14. Life underwater, Mortality, Picoplankton, ComputingMilieux_MISCELLANEOUS, Shellfish, 030304 developmental biology, 0303 health sciences, Ciliates, biology, business.industry, Balanion, fungi, food and beverages, Pelagic zone, 04 agricultural and veterinary sciences, Pacific oyster, equipment and supplies, biology.organism_classification, Magallana gigas, Uronema, OsHV-1 mu Var, Crassostrea gigas, [SDE]Environmental Sciences, 040102 fisheries, bacteria, 0401 agriculture, forestry, and fisheries, Crassostrea, business
Abstract: Oysters modify the planktonic microbial community structure by their filtration and NH4 excretion activities. While many studies have been conducted on this subject with adult oysters, none had been carried out in situ with juveniles. Pacific oyster juveniles (Magallana gigas, previously Crassostrea gigas) died massively all over the world since 2008 in relation with OsHV-1 infection. During mortality episodes, sick and dead oysters are not separated from healthy live ones, and left to decay in the surrounding environment, with unknown consequences for the nutrient cycle and planktonic microbial components (PMC). The present study aimed to elucidate for the first time the interactions between oyster juveniles and PMC during a mortality episode. Innovative 425-L pelagic chambers were deployed weekly in situ around oyster lanterns along a stocking-density gradient in the Thau Mediterranean lagoon (France) before, during and after an oyster mortality episode, from April to May 2015. This study reveals (i) significant changes of planktonic microbial community structure during mortality episodes, with a proliferation of picoplankton (
Published: 2019

10. Benthic-pelagic coupling under juvenile oyster influence in a French Mediterranean coastal lagoon (Thau Lagoon)

Author: Élise Lacoste, Béatrice Bec, Patrik Le Gall, Fehmi Boufahja, Patrick Raimbault, Gregory Messiaen, Vincent Ouisse, Emmanuelle Roque d’Orbcastel, Dominique Munaron, Annie Fiandrino, Franck Lagarde, Sébastien Mas, Myriam Callier, Nabila Gaertner-Mazouni, Marion Richard, 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)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Laboratoire Service d' Experimentations Aquacoles [Palavas les Flots] (LSEA MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), 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), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Station IFREMER de Palavas-les-Flots, Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD), and Université de la Polynésie Française (UPF)
Subjects: Shellfish farming, Benthic fluxes, [SDE.MCG]Environmental Sciences/Global Changes, fungi, Phytoplankton, Biodeposition, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Aquatic Science, Coastal lagoon, Oceanography, geographic locations
Abstract: International audience; The aim of the present work was to test the influence of juvenile oyster culture on benthic-pelagic coupling in the French Mediterranean Thau Lagoon. Although the period of juvenile growth induces the introduction of millions of juvenile oysters in the lagoon over a short duration, the effects on the water-column and on the benthic ecosystem are poorly known. Using a multiple ecological approach, water column parameters, sedimentation rates, sediment characteristics and benthic fluxes were monitored on three occasions during the oyster pre-growth period, from October to December, at two sites inside the farming area and two sites outside the farming area that served as reference. In the water column, results showed a significant lower ratio between total phytoplankton biomass (chlorophyll-a) and degraded pigments (pheopigment), a significant increase in the contribution of phytoplankton containing chlorophyll-b (ie chlorophytes) to total phytoplankton biomass and a significant decrease in the contribution of phytoplankton containing chlorophyll-c (mainly diatoms) to the total phytoplankton biomass at farm sites, attributed to the grazing pressure caused by juvenile oysters on large particles, as described for adult oysters. No significant effect was observed at the benthic interface during this period, due to the dispersion of the small quantities of biodeposit produced by juveniles in the low water temperature conditions. A multivariate approach supported the effect of juvenile oysters on the water column and revealed a trend in benthic conditions with farm sites being distinct from the reference ones. The long farming history of the lagoon could have shaped sediment properties such that farming areas maintain different benthic conditions.
Published: 2022

11. Use of physiological information based on grayscale images to improve mass spectrometry imaging data analysis from biological tissues

Author: A. Torro, Luis Fernandez, Santiago Marco, Pierre Martineau, Christian Larroque, A. de Juan, Céline Gongora, Sílvia Mas, G. Erschov, Nicole Bec, Information – Technologies – Analyse Environnementale – Procédés Agricoles (UMR ITAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), 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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut du Cancer de Montpellier (ICM), Universitat de Barcelona (UB), Institute for Bioengineering of Catalonia [Barcelona] (IBEC), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Genotypes et Phenotypes Tumoraux, Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Recherche en Cancérologie de Montpellier (IRCM - U1194 Inserm - UM), CRLCC Val d'Aurelle - Paul Lamarque-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire d'Informatique, de Modélisation et d'optimisation des Systèmes (LIMOS), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Sigma CLERMONT (Sigma CLERMONT)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure des Mines de St Etienne, Department de Quimica Analitica, Department of Geophysics and Planetary Sciences [Tel Aviv], Tel Aviv University [Tel Aviv], CRLCC Val d'Aurelle - Paul Lamarque-Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), This work is part of the BEST Postdoctoral Program, funded by the European Commission under Horizon 2020 Marie Skłodowska-Curie Actions COFUND scheme (Grant Agreement no. 712754) and by the Severo Ochoa program of the Spanish Ministry of Science and Competitiveness (Grant SEV-2014-0425 (2015–2019)). A.J. acknowledges financial support from the Catalan government through project 2017 SGR 753 and the Spanish government through project CTQ2015-66254-C2-2-P., European Project: 712754,H2020,H2020-MSCA-COFUND-2015,BEST(2017), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])
Subjects: [SDV.BIO]Life Sciences [q-bio]/Biotechnology, Color, Mice, Nude, [SDV.CAN]Life Sciences [q-bio]/Cancer, 02 engineering and technology, 01 natural sciences, Biochemistry, Grayscale, Mass spectrometry imaging, Analytical Chemistry, Neoplasms, Image Processing, Computer-Assisted, MALDI-MSI, Environmental Chemistry, Preprocessor, Animals, Cluster Analysis, Humans, [CHIM]Chemical Sciences, Segmentation, Least-Squares Analysis, Cluster analysis, K-means, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Local rank constraints, business.industry, Chemistry, Dimensionality reduction, 010401 analytical chemistry, k-means clustering, Pattern recognition, Image segmentation, 021001 nanoscience & nanotechnology, HCT116 Cells, 0104 chemical sciences, MCR-ALS, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Multivariate Analysis, Heterografts, Regression Analysis, Female, Artificial intelligence, Grayscale images, 0210 nano-technology, business, Algorithms
Abstract: International audience; The characterization of cancer tissues by matrix-assisted laser desorption ionization-mass spectrometry images (MALDI-MSI) is of great interest because of the power of MALDI-MS to understand the composition of biological samples and the imaging side that allows for setting spatial boundaries among tissues of different nature based on their compositional differences.In tissue-based cancer research, information on the spatial location of necrotic/tumoral cell populations can be approximately known from grayscale images of the scanned tissue slices. This study proposes as a major novelty the introduction of this physiologically-based information to help in the performance of unmixing methods, oriented to extract the MS signatures and distribution maps of the different tissues present in biological samples. Specifically, the information gathered from grayscale images will be used as a local rank constraint in Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) for the analysis of MALDI-MSI of cancer tissues. The use of this constraint, setting absence of certain kind of tissues only in clear zones of the image, will help to improve the performance of MCR-ALS and to provide a more reliable definition of the chemical MS fingerprint and location of the tissues of interest.The general strategy to address the analysis of MALDI-MSI of cancer tissues will involve the study of the MCR-ALS results and the posterior use of MCR-ALS scores as dimensionality reduction for image segmentation based on K-means clustering. The resolution method will provide the MS signatures and their distribution maps for each tissue in the sample. Then, the resolved distribution maps for each biological component (MCR scores) will be submitted as initial information to K-means clustering for image segmentation to obtain information on the boundaries of the different tissular regions in the samples studied. MCR-ALS prior to K-means not only provides the desired dimensionality reduction, but additionally resolved non-biological signal contributions are not used and the weight given to the different biological components in the segmentation process can be modulated by suitable preprocessing methods.
Published: 2019

12. MALDI imaging mass spectrometry and chemometric tools to discriminate highly similar colorectal cancer tissues

Author: Santiago Marco, Christian Larroque, A. Torro, A. de Juan, Nicole Bec, Sílvia Mas, Céline Gongora, Pierre Martineau, Luis Fernandez, Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut du Cancer de Montpellier (ICM), Universitat de Barcelona (UB), Institute for Bioengineering of Catalonia [Barcelona] (IBEC), Information – Technologies – Analyse Environnementale – Procédés Agricoles (UMR ITAP), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), and 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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: MALDI imaging, Colorectal cancer, [SDV]Life Sciences [q-bio], Mice, Nude, 02 engineering and technology, Computational biology, 01 natural sciences, Somatic evolution in cancer, Analytical Chemistry, Cell Line, Tumor, Genetic variation, medicine, Animals, Humans, [CHIM]Chemical Sciences, Least-Squares Analysis, ComputingMilieux_MISCELLANEOUS, Chemistry, 010401 analytical chemistry, Discriminant Analysis, Cancer, 021001 nanoscience & nanotechnology, medicine.disease, Isogenic human disease models, 0104 chemical sciences, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Cancer cell, Adenocarcinoma, Colorectal Neoplasms, 0210 nano-technology
Abstract: Intratumour heterogeneity due to cancer cell clonal evolution and microenvironment composition and tumor differences due to genetic variations between patients suffering of the same cancer pathology play a crucial role in patient response to therapies. This study is oriented to show that matrix-assisted laser-desorption ionization-Mass spectrometry imaging (MALDI-MSI), combined with an advanced multivariate data processing pipeline can be used to discriminate subtle variations between highly similar colorectal tumors. To this aim, experimental tumors reproducing the emergence of drug-resistant clones were generated in athymic mice using subcutaneous injection of different mixes of two isogenic cell lines, the irinotecan-resistant HCT116-SN50 (R) and its sibling human colon adenocarcinoma sensitive cell line HCT116 (S). Because irinotecan-resistant and irinotecan-sensitive are derived from the same original parental HCT116 cell line, their genetic characteristics and molecular compositions are closely related. The multivariate data processing pipeline proposed relies on three steps: (a) multiset multivariate curve resolution (MCR) to separate biological contributions from background; (b) multiset K-means segmentation using MCR scores of the biological contributions to separate between tumor and necrotic parts of the tissues; and (c) partial-least squares discriminant analysis (PLS-DA) applied to tumor pixel spectra to discriminate between R and S tumor populations. High levels of correct classification rates (0.85), sensitivity (0.92) and specificity (0.77) for the PLS-DA classification model were obtained. If previously labelled tissue is available, the multistep modeling strategy proposed constitutes a good approach for the identification and characterization of highly similar phenotypic tumor subpopulations that could be potentially applicable to any kind of cancer tissue that exhibits substantial heterogeneity.
Published: 2020

13. Significant Change in Marine Plankton Structure and Carbon Production After the Addition of River Water in a Mesocosm Experiment

Author: J. Nouguier, Francesca Vidussi, Marc Bouvy, Thierry Bouvier, E. Le Floc'h, S. Boyer, Eric Fouilland, Delphine Bonnet, Emma Rochelle-Newall, David Pecqueur, Behzad Mostajir, Hongmei Jing, Sébastien Mas, Aurore Trottet, Christophe Vasseur, Catharina Alves-de-Souza, Cécile Roques, E. Hatey, Christophe Leboulanger, Hongbin Liu, Laure Guillou, Christian Salles, Marie-George Tournoud, 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), 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), 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), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), 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)-Centre National de la Recherche Scientifique (CNRS), Honk Kong University of Sciences and Technology, Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-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), French national EC2CO program University of Montpellier 2 French Ministry of Education and Research UMR ECOSYM BEcologie des Systemes Marins Cotiers 5119 CNRS Institute of Ecology and Environment (InEE), University of Montpellier 2 IFR Armand Sabatier 129 Reseaux Trophiques Aquatiques CNRS-GDR2476 Region Languedoc-Roussillon, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), 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), Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-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), Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) ), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff (SBR), and 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)
Subjects: 0106 biological sciences, DYNAMICS, Rotifera, Fresh Water, NUTRIENT, 01 natural sciences, Mesocosm, FLASH-FLOOD, Flood impact, PHYTOPLANKTON, SALINITY, ComputingMilieux_MISCELLANEOUS, geography.geographical_feature_category, Ecology, biology, Potentially harmful species, MEDITERRANEAN COASTAL LAGOON, Planktonic food web, Plankton, 6. Clean water, Salt marsh, EUTROPHICATION, [SDE]Environmental Sciences, France, BIOVOLUME, Food Chain, Soil Science, Coastal ecosystems, 010603 evolutionary biology, Rivers, Phytoplankton, Potentially, Animals, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, geography, Picoeukaryote, Bacteria, Brackish water, 010604 marine biology & hydrobiology, fungi, Bacterioplankton, harmful species, biology.organism_classification, Carbon, 13. Climate action, CALANOIDA, SALT MARSHES, Eutrophication
Abstract: International audience; Rivers are known to be major contributors to eutrophication in marine coastal waters, but little is known on the short-term impact of freshwater surges on the structure and functioning of the marine plankton community. The effect of adding river water, reducing the salinity by 15 and 30%, on an autumn plankton community in a Mediterranean coastal lagoon (Thau Lagoon, France) was determined during a 6-day mesocosm experiment. Adding river water brought not only nutrients but also chlorophyceans that did not survive in the brackish mesocosm waters. The addition of water led to initial increases (days 1-2) in bacterial production as well as increases in the abundances of bacterioplankton and picoeukaryotes. After day 3, the increases were more significant for diatoms and dinoflagellates that were already present in the Thau Lagoon water (mainly Pseudo-nitzschia spp. group delicatissima and Prorocentrum triestinum) and other larger organisms (tintinnids, rotifers). At the same time, the abundances of bacterioplankton, cyanobacteria, and picoeukaryote fell, some nutrients (NH4 (+), SiO4 (3-)) returned to pre-input levels, and the plankton structure moved from a trophic food web based on secondary production to the accumulation of primary producers in the mesocosms with added river water. Our results also show that, after freshwater inputs, there is rapid emergence of plankton species that are potentially harmful to living organisms. This suggests that flash flood events may lead to sanitary issues, other than pathogens, in exploited marine areas.
Published: 2017

14. Primary marine aerosol physical flux and chemical composition during a nutrient enrichment experiment in mesocosms in the Mediterranean Sea

Author: Schwier, Allison, Sellegri, Karine, Mas, Sébastien, Charrìère, Bruno, Pey, Jorge, Rose, Clémence, Temime-Roussel, Brice, Jaffrezo, Jean-Luc, Parin, David, Picard, David, Ribeiro, Mickaël, Roberts, Greg, SEMPERE, Richard, Marchand, Nicolas, D'ANNA, Barbara, Laboratoire de Météorologie Physique - Clermont Auvergne (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-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)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Laboratoire Chimie de l'environnement (LCE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre national de recherches météorologiques (CNRM), Météo France-Centre National de la Recherche Scientifique (CNRS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Dynamique des capacités humaines et des conduites de santé (EPSYLON), Université Montpellier 1 (UM1)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Montpellier (UM), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines (LMGEM), Centre National de la Recherche Scientifique (CNRS)-Université de la Méditerranée - Aix-Marseille 2, Spanish Geological Survey, Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, ANR-11-BS56-0022,SAM,Source d'aérosols marins dans l'atmosphère méditerranéenne(2011), Université Montpellier 1 (UM1)-Université Paul-Valéry - Montpellier 3 (UM3)-Université de Montpellier (UM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), SYSCO (GIPSA-SYSCO), Département Automatique (GIPSA-DA), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), ANR: 022 04,SIMI 5/6,Environnement, terre et espace, Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC), 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), Agence Nationale de la Recherche (France), and Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, nutriente, composición, aerosol, [SDE.MCG]Environmental Sciences/Global Changes, propiedad fisicoquímica, Mar Mediterráneo, enriquecimiento
Abstract: While primary marine aerosol (PMA) is an important part of global aerosol total emissions, its chemical composition and physical flux as a function of the biogeochemical properties of the seawater still remain highly uncharacterized due to the multiplicity of physical, chemical and biological parameters that are involved in the emission process. Here, two nutrient-enriched mesocosms and one control mesocosm, both filled with Mediterranean seawater, were studied over a 3-week period. PMA generated from the mesocosm waters were characterized in term of chemical composition, size distribution and size-segregated cloud condensation nuclei (CCN), as a function of the seawater chlorophyll a (Chl a) concentration, pigment composition, virus and bacteria abundances. The aerosol number size distribution flux was primarily affected by the seawater temperature and did not vary significantly from one mesocosm to the other. The aerosol number size distribution flux was primarily affected by the seawater temperature and did not vary significantly from one mesocosm to the other. Particle number and CCN aerosol fluxes increase by a factor of 2 when the temperature increases from 22 to 32 °C, for all particle submicron sizes. This effect, rarely observed in previous studies, could be specific to oligotrophic waters and/or to this temperature range. In all mesocosms (enriched and control mesocosms), we detected an enrichment of calcium (+500 %) and a deficit in chloride (−36 %) in the submicron PMA mass compared to the literature inorganic composition of the seawater. There are indications that the chloride deficit and calcium enrichment are linked to biological processes, as they are found to be stronger in the enriched mesocosms. This implies a non-linear transfer function between the seawater composition and PMA composition, with complex processes taking place at the interface during the bubble bursting. We found that the artificial phytoplankton bloom did not affect the CCN activation diameter (Dp, 50, average = 59.85±3.52 nm and Dp,50,average = 93.42±5.14 nm for supersaturations of 0.30 and 0.15 % respectively) or the organic fraction of the submicron PMA (average organic to total mass = 0.31±0.07) compared to the control mesocosm. Contrary to previous observations in natural bloom mesocosm experiments, the correlation between the particle organic fraction and the seawater Chl a was poor, indicating that Chl a is likely not a straightforward proxy for predicting, on a daily scale, PMA organic fraction in models for all types of sea and ocean waters. Instead, the organic fraction of the Aitken mode particles were more significantly linked to heterotrophic flagellates, viruses and dissolved organic carbon (DOC). We stress that different conclusions may be obtained in natural (non-enriched) or non-oligotrophic systems., Laboratoire de Météorologie Physique, Observatoire de Physique du Globe de Clermont-Ferrand, Francia, Centre d’écologie marine expérimentale, Université de Montpellier, Francia, Centre de Formation et de Recherche sur les Environnements Méditerranéens, Université de Perpignan, Francia, Aix-Marseille Université, Francia, Unidad de Zaragoza, Instituto Geológico y Minero de España, España, Université Grenoble Alpes, Francia, Centre National de Recherches Météorologiques, Francia, Mediterranean Institute of Oceanography, Aix-Marseille University, Francia, Mediterranean Institute of Oceanography, Centre National de la Recherche Scientifique, Francia, Mediterranean Institute of Oceanography, Institut de Recherche pour le Développement, Francia, Institut de Recherches Sur la Catalyse et l’Environnement de Lyon, Université Claude Bernard Lyon I, Francia
Published: 2017

15. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

Author: Anastasia Tsiola, Iordanis Magiopoulos, Paraskevi Mara, Romain Pete, Stella Psarra, Stilianos Fodelianakis, Tsuneo Tanaka, Paraskevi Pitta, Behzad Mostajir, 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), Laboratoire d'océanographie de Villefranche (LOV), 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)-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 d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Soil Science, 01 natural sciences, Water column, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Phytoplankton, Botany, Mediterranean Sea, Seawater, 14. Life underwater, Autotroph, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Prochlorococcus, Synechococcus, Autotrophic Processes, Ecology, biology, Bacteria, 010604 marine biology & hydrobiology, fungi, Eukaryotic phytoplankton, Eukaryota, Pelagic zone, Heterotrophic Processes, Plankton, Heterotrophic prokaryotes, biology.organism_classification, Viruses, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Microcosm
Abstract: International audience; The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.
Published: 2015

16. Coupling algal biomass production and anaerobic digestion : production assessment of some native temperate and tropical microalgae

Author: Christophe Vasseur, Jean-Philippe Steyer, Eric Fouilland, Bruno Sialve, Emilie Le Floc'h, Claire Carré, Bruno Marty, Christophe Leboulanger, Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-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), Station Méditerranéenne de l'Environnement Littoral, Université Montpellier 2 - Sciences et Techniques (UM2), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Naskeo Environnement, Laboratoire de Biotechnologie de l'Environnement [Narbonne] (LBE), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), 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)-Institut National de la Recherche Agronomique (INRA), ANR-08-BIOE-11 French National Research Agency, under the Symbiose project, Scientific Council of University Montpellier II (METTRO project), ANR-08-BIOE-0011,SYMBIOSE,Etude et Optimisation du Couplage MicroAlgue-Bactérie Anaérobie pour la Production d'Energie par voie biologique à partir de biomasse primaire et de déchets organiques(2008), Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1), and Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)
Subjects: 020209 energy, [SDV]Life Sciences [q-bio], Digestates, Nannochloris, Biomass, 02 engineering and technology, 010501 environmental sciences, Cyanobacteria, 7. Clean energy, 01 natural sciences, Biogas, Chlorophyta, Botany, 0202 electrical engineering, electronic engineering, information engineering, Microalgae, Waste Management and Disposal, Scenedesmus, 0105 earth and related environmental sciences, biology, Renewable Energy, Sustainability and the Environment, Forestry, biology.organism_classification, 6. Clean water, Anaerobic digestion, Wastewaters, Wastewater, Biofuel, Environmental chemistry, Digestate, Extreme natural environments, Agronomy and Crop Science
Abstract: Coupling algal biomass production and anaerobic digestion is one of the most promising bioprocesses for economically viable algal production. This study assesses the production rates of some native microalgae growing in media supplemented with algal digestate, urban wastewater or digested sludge. Native microalgal populations isolated from temperate freshwaters ( Scenedesmus spp.) and marine ecosystems ( Nannochloris spp.) had the highest potential production rates (about 100 mg DW L −1 d −1 ) with algal digestate at about 20% loading ratio. However, no growth was measured for Nannochloris spp., when the ammonium concentration exceeded 100 mg L −1 although Scenedesmus spp. appeared to be tolerant to higher NH 4 + concentrations. Very low production rates, or no growth, were measured when microalgae isolated from high salinity waters ( Dunaliella salina , Lyngbya aestuarii ) were used, suggesting that populations well adapted to extreme environmental conditions are not suitable candidates for growing on wastewater or anaerobic digestate.
Published: 2014

17. Bacterial carbon dependence on freshly produced phytoplankton exudates under different nutrient availability and grazing pressure conditions in coastal marine waters

Author: Télesphore Sime-Ngando, Delphine Bonnet, Thierry Bouvier, Francesca Vidussi, Behzad Mostajir, Imma Tolosa, Marc Bouvy, Corinne Bouvier, Eric Fouilland, Emilie Le Floc'h, Patrice Got, Cécile Roques, Richard Sempéré, Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-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), Environment Laboratories (IAEA), International Atomic Energy Agency [Vienna] (IAEA), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), 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 Microorganismes : Génome et Environnement (LMGE), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)
Subjects: 0106 biological sciences, Food Chain, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, coastal waters, Biology, 01 natural sciences, Applied Microbiology and Biotechnology, Microbiology, Algal bloom, Grazing pressure, Nutrient, Grazing, Phytoplankton, Botany, Mediterranean Sea, Seawater, 14. Life underwater, Biomass, bacteria, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, 2. Zero hunger, Biomass (ecology), Carbon Isotopes, Ecology, 010604 marine biology & hydrobiology, fungi, Heterotrophic Processes, interactions, Lipids, Carbon, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, Microbial population biology, chemistry, 13. Climate action, Environmental chemistry, phytoplankton, carbon coupling, France, Seasons
Abstract: International audience; The effects of grazing pressure and inorganic nutrient availability on the direct carbon transfer from freshly produced phytoplankton exudates to heterotrophic bacteria biomass production were studied in Mediterranean coastal waters. The short-term incorporation of 13C (H13CO3) in phytoplankton and bacterial lipid biomarkers was measured as well as the total bacterial carbon production (BP), viral lysis and the microbial community structure under three experimental conditions: (1) High inorganic Nutrient and High Grazing (HN + HG), (2) High inorganic Nutrient and Low Grazing (HN + LG) and (3) under natural in situ conditions with Low inorganic Nutrient and High Grazing (LN + HG) during spring. Under phytoplankton bloom conditions (HN + LG), the bacterial use of freshly produced phytoplankton exudates as a source of carbon, estimated from 13C enrichment of bacterial lipids, contributed more than half of the total bacterial production. However, under conditions of high grazing pressure on phytoplankton with or without the addition of inorganic nutrients (HN + HG and LN + HG), the 13C enrichment of bacterial lipids was low compared with the high total bacterial production. BP therefore seems to depend mainly on freshly produced phytoplankton exudates during the early phase of phytoplankton bloom period. However, BP seems mainly relying on recycled carbon from viral lysis and predators under high grazing pressure.
Published: 2014

18. A new transportable floating mesocosm platform with autonomous sensors for real-time data acquisition and transmission for studying the pelagic food web functioning

Author: Mostajir, Behzad, Le Floc'h, Emilie, Mas, Sébastien, Pete, Romain, Parin, David, Nouguier, Jean, Fouilland, Eric, Vidussi, Francesca, 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), Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), 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), Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Ecologie des systèmes marins côtiers (Ecosym), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-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)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1)
Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2013

19. Impact of a river flash flood on microbial carbon and nitrogen production in a Mediterranean Lagoon (Thau Lagoon, France)

Author: Marc Bouvy, Behzad Mostajir, Sébastien Mas, Aurore Trottet, Marie-George Tournoud, Francesca Vidussi, Emma Rochelle-Newall, Christian Salles, Christine Roques, Eric Fouilland, E. Hatey, E. Le Floc'h, Chrystelle Bancon-Montigny, David Pecqueur, J. Nouguier, Claire Rodier, Jean-Louis Gonzalez, Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-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), Hydrosciences Montpellier (HSM), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), 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), 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), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Universidad Politécnica de Valencia, 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), Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), UR 103 Camélia, Institut de Recherche pour le Développement (IRD), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Laboratoire de génie chimique [ancien site de Basso-Cambo] (LGC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de Synthèse et Fonctionnalisation de Céramiques (UMR 3080), Saint Gobain, 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), 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)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, metal contaminants, Aquatic Science, Oceanography, 01 natural sciences, phytoplankton and bacteria production, Dissolved organic carbon, Phytoplankton, Trace metal, 14. Life underwater, Turbidity, Mediterranean coastal waters, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Hydrology, Brackish water, DIN uptake rates, 010604 marine biology & hydrobiology, Phosphorus, Sedimentation, Nitrogen, 6. Clean water, chemistry, Environmental chemistry, [SDE]Environmental Sciences, Environmental science, river discharge
Abstract: Over half of the total nitrogen, phosphorus, silicate and dissolved organic carbon (DOC) loading was discharged from the Wile River into the Thau Lagoon waters within the first five days of what was considered to be the autumn flash flood period. Such loads represented about 8% and 3% of the yearly averaged total nitrogen and phosphorus load in Thau Lagoon, respectively. Although this event affected >20% of the total lagoon volume, river trace metal loads contributed apparently only weakly to the increase in labile trace metal concentrations in the lagoon surface waters. Differences between theoretical dilution values and observed values were also noticed for phosphate, silicate and dissolved organic carbon (DOC) concentrations. DOC losses (10-50%) mainly through flocculation, together with the substantial increases in some metallic contaminants such as Zn (from 6 to >30 mu g L-1) observed during the flash flood in saline lagoon waters, may have limited the carbon production of bacterial communities. The potential osmotic shock and the increase in turbidity may mainly explain the low phytoplankton C turnover rates (average of 0.02 h(-1)) measured in brackish waters (
Published: 2012

20. Dynamics of microbial planktonic food web components during a river flash flood in a Mediterranean coastal lagoon

Author: Marie-George Tournoud, David Pecqueur, Eric Fouilland, Christian Salles, Sébastien Mas, Emilie Le Floc'h, Francesca Vidussi, Cécile Roques, Behzad Mostajir, 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), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Hydrosciences Montpellier (HSM), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Biomass (ecology), Microbial food web, Flood myth, Ecology, 010604 marine biology & hydrobiology, Aquatic Science, Plankton, 010603 evolutionary biology, 01 natural sciences, Food web, Mediterranean sea, 13. Climate action, Benthic zone, Nanophytoplankton, Environmental science, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS
Abstract: Episodic river flash floods, characteristic of Mediterranean climates, are suspected to greatly affect the functioning of microbial food webs. For the first time, the abundance, biomass and diversities of microbial food web components were studied before and during 4 consecutive days after a flash flood that occurred in November 2008, in the surface waters of five stations along a salinity gradient from 20 to 36 in the Thau lagoon. Eukaryotic pico- and nanophytoplankton were discharged from the river into the lagoon and increased by 30- and 70-fold, respectively. Bacteria increased by only 2-fold in the lagoon, from around 4–8 × 106 cells ml−1, probably benefiting from river nutrient input. Chlorophyll a increased 4-fold, and pigment biomarkers showed that the dinophyceae, prasinophyceae and prymnesiophyceae were sensitive to the flood perturbation, whereas the bacillariophyceae, cryptophyceae and chlorophyceae were resistant and/or transported to the lagoon from the river. Predator responses were more complex as total heterotrophic flagellate abundance decreased slightly, whereas those of specific naked ciliates increased, particularly for Uronema sp. The flood also induced a specific change in diversity, from a community dominated by Strobilidium spiralis to a community dominated by Uronema sp. The tintinnid community was particularly sensitive to the flood event as the abundance of all species decreased greatly. The high increases in biomass, mainly brought by the river during the flood, could have eventually sedimented to the benthic layer and/or been transported further into the lagoon, supporting the pelagic food web, or have even been exported to the Mediterranean Sea.
Published: 2011

21. Trophic interactions between viruses, bacteria and nanoflagellates under various nutrient conditions and simulated climate change

Author: Bouvy, M., Bettarel, Y., Bouvier, C., Domaizon, I., Jacquet, S., Le Floc'H, E., Montanié, H., Mostajir, B., Sime-Ngando, Télesphore, Torréton, J. P., Vidussi, F., Bouvier, T., Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-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), Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Institut National de la Recherche Agronomique (INRA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de la Recherche Agronomique (INRA), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Université d'Auvergne - Clermont-Ferrand I (UdA), Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1), LIttoral ENvironnement et Sociétés (LIENSs), and La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Principal Component Analysis, MARINE VIRUSES, Food Chain, Bacteria, Ultraviolet Rays, Climate Change, Population Dynamics, UV-RADIATION, Temperature, HETEROTROPHIC BACTERIA, Phytoplankton, Viruses, Mediterranean Sea, MESO-EUTROPHIC RESERVOIR, Seawater, CANYON-SHAPED RESERVOIR, AQUATIC ENVIRONMENTS, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Water Microbiology, ULTRAVIOLET-B RADIATION, LAKE BOURGET FRANCE, SYBR GREEN-I, COASTAL WATERS, Ecosystem
Abstract: International audience; Population dynamics in the microbial food web are influenced by resource availability and predator/parasitism activities. Climatic changes, such as an increase in temperature and/or UV radiation, can also modify ecological systems in many ways. A series of enclosure experiments was conducted using natural microbial communities from a Mediterranean lagoon to assess the response of microbial communities to top-down control [grazing by heterotrophic nanoflagellates (HNF), viral lysis] and bottom-up control (nutrients) under various simulated climatic conditions (temperature and UV-B radiations). Different biological assemblages were obtained by separating bacteria and viruses from HNF by size fractionation which were then incubated in whirl-Pak bags exposed to an increase of 3°C and 20% UV-B above the control conditions for 96 h. The assemblages were also provided with an inorganic and organic nutrient supply. The data show (i) a clear nutrient limitation of bacterial growth under all simulated climatic conditions in the absence of HNF, (ii) a great impact of HNF grazing on bacteria irrespective of the nutrient conditions and the simulated climatic conditions, (iii) a significant decrease in burst size (BS) (number of intracellular lytic viruses per bacterium) and a significant increase of VBR (virus to bacterium ratio) in the presence of HNF, and (iv) a much larger temperature effect than UV-B radiation effect on the bacterial dynamics. These results show that top-down factors, essentially HNF grazing, control the dynamics of the lagoon bacterioplankton assemblage and that short-term simulated climate changes are only a secondary effect controlling microbial processes.
Published: 2011

22. Surface ocean microbiota determine cloud precursors

Author: Julia Uitz, Barbara D'Anna, Alessia Nicosia, Clémence Rose, Maija Peltola, Melilotus Thyssen, Anja Engel, Gérald Grégori, Evelyn Freney, Birthe Zäncker, Alexia Saint-Macary, Karine Sellegri, Nicholas Meskhidze, Cliff S. Law, Karine Desboeufs, Nils Haëntjens, Cécile Guieu, Sébastien Mas, David Picard, Jonathan V. Trueblood, Dominique Lefèvre, Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), 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), 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), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), University of Maine - School of Marine Sciences, Centre d'Ecologie marine expérimentale (MEDIMEER), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), National Institute of Water and Atmospheric Research [Wellington] (NIWA), University of Otago [Dunedin, Nouvelle-Zélande], Laboratoire Chimie de l'environnement (LCE), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), North Carolina State University [Raleigh] (NC State), University of North Carolina System (UNC), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: 0301 basic medicine, 010504 meteorology & atmospheric sciences, Surface ocean, Range (biology), Climate, Science, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Atmospheric sciences, 01 natural sciences, Article, 03 medical and health sciences, Nanophytoplankton, Phytoplankton, Atmospheric science, Cloud condensation nuclei, Seawater, 14. Life underwater, 0105 earth and related environmental sciences, Marine biology, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, Atmosphere, Microbiota, Sea spray, 030104 developmental biology, 13. Climate action, Medicine, Climate model
Abstract: One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions. This sensitivity of CCN number fluxes to ocean biology is currently unaccounted for in climate models yet our measurements indicate that it influences fluxes by more than one order of magnitude over the range of phytoplankton investigated.
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23. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment.

Author: Tsiola A, Pitta P, Fodelianakis S, Pete R, Magiopoulos I, Mara P, Psarra S, Tanaka T, and Mostajir B
Subjects: Autotrophic Processes, Bacteria classification, Bacteria isolation & purification, Eukaryota classification, Eukaryota isolation & purification, Heterotrophic Processes, Mediterranean Sea, Seawater chemistry, Viruses classification, Viruses isolation & purification, Bacteria metabolism, Eukaryota metabolism, Seawater microbiology, Viruses metabolism
Abstract: The growth rates of planktonic microbes in the pelagic zone of the Eastern Mediterranean Sea are nutrient limited, but the type of limitation is still uncertain. During this study, we investigated the occurrence of N and P limitation among different groups of the prokaryotic and eukaryotic (pico-, nano-, and micro-) plankton using a microcosm experiment during stratified water column conditions in the Cretan Sea (Eastern Mediterranean). Microcosms were enriched with N and P (either solely or simultaneously), and the PO4 turnover time, prokaryotic heterotrophic activity, primary production, and the abundance of the different microbial components were measured. Flow cytometric and molecular fingerprint analyses showed that different heterotrophic prokaryotic groups were limited by different nutrients; total heterotrophic prokaryotic growth was limited by P, but only when both N and P were added, changes in community structure and cell size were detected. Phytoplankton were N and P co-limited, with autotrophic pico-eukaryotes being the exception as they increased even when only P was added after a 2-day time lag. The populations of Synechococcus and Prochlorococcus were highly competitive with each other; Prochlorococcus abundance increased during the first 2 days of P addition but kept increasing only when both N and P were added, whereas Synechococcus exhibited higher pigment content and increased in abundance 3 days after simultaneous N and P additions. Dinoflagellates also showed opportunistic behavior at simultaneous N and P additions, in contrast to diatoms and coccolithophores, which diminished in all incubations. High DNA content viruses, selective grazing, and the exhaustion of N sources probably controlled the populations of diatoms and coccolithophores.
Published: 2016
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23 results on '"Centre d'Ecologie marine expérimentale (MEDIMEER)"'

1. Data quality control considerations in multivariate environmental monitoring: experience of the French coastal network SOMLIT

2. Impact of anoxia and oyster mortality on nutrient and microbial planktonic components: A mesocosm study

3. Brownification reduces oxygen gross primary production and community respiration and changes the phytoplankton community composition: An in situ mesocosm experiment with high‐frequency sensor measurements in a North Atlantic bay

4. Metabolic responses of plankton to warming during different productive seasons in coastal Mediterranean waters revealed by in situ mesocosm experiments

5. Functional Stability of a Coastal Mediterranean Plankton Community During an Experimental Marine Heatwave

6. Le réchauffement désavantage le phytoplancton au profit des bactéries pendant une efflorescence printanière dans la lagune de Thau en Méditerranée

7. Co-occurrence networks reveal the central role of temperature in structuring the plankton community of the Thau Lagoon

8. Silicate marine electrochemical sensor

9. Changes in planktonic microbial components in interaction with juvenile oysters during a mortality episode in the Thau lagoon (France)

10. Benthic-pelagic coupling under juvenile oyster influence in a French Mediterranean coastal lagoon (Thau Lagoon)

11. Use of physiological information based on grayscale images to improve mass spectrometry imaging data analysis from biological tissues

12. MALDI imaging mass spectrometry and chemometric tools to discriminate highly similar colorectal cancer tissues

13. Significant Change in Marine Plankton Structure and Carbon Production After the Addition of River Water in a Mesocosm Experiment

14. Primary marine aerosol physical flux and chemical composition during a nutrient enrichment experiment in mesocosms in the Mediterranean Sea

15. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment

16. Coupling algal biomass production and anaerobic digestion : production assessment of some native temperate and tropical microalgae

17. Bacterial carbon dependence on freshly produced phytoplankton exudates under different nutrient availability and grazing pressure conditions in coastal marine waters

18. A new transportable floating mesocosm platform with autonomous sensors for real-time data acquisition and transmission for studying the pelagic food web functioning

19. Impact of a river flash flood on microbial carbon and nitrogen production in a Mediterranean Lagoon (Thau Lagoon, France)

20. Dynamics of microbial planktonic food web components during a river flash flood in a Mediterranean coastal lagoon

21. Trophic interactions between viruses, bacteria and nanoflagellates under various nutrient conditions and simulated climate change

22. Surface ocean microbiota determine cloud precursors

23. Nutrient Limitation in Surface Waters of the Oligotrophic Eastern Mediterranean Sea: an Enrichment Microcosm Experiment.

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23 results on '"Centre d'Ecologie marine expérimentale (MEDIMEER)"'

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