Author: "Gabriel Gorsky" / Topic: 010504 meteorology & atmospheric sciences - Searchworks@Jio Institute Digital Library Search Results

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1. Diel cycle of sea spray aerosol concentration

Author: Guillaume Bourdin, J. Michel Flores, Sarah Romac, Fabien Lombard, Guy Dagan, Assaf Vardi, Christian R. Voolstra, Alexander B. Kostinski, Ilan Koren, Naama Lang-Yona, Yinon Rudich, Emmanuel Boss, Gabriel Gorsky, Nils Haëntjens, Orit Altaratz, Matthew B. Sullivan, Miri Trainic, Department of Earth and Planetary Science [Rehovot], Weizmann Institute of Science [Rehovot, Israël], University of Maine, Michigan Technological University (MTU), 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), University of Maine - School of Marine Sciences, and Griffith University [Brisbane]
Subjects: Atmospheric chemistry, 010504 meteorology & atmospheric sciences, Science, General Physics and Astronomy, Sunset, Atmospheric sciences, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Atmosphere, 03 medical and health sciences, ddc:570, Sunrise, 14. Life underwater, Diel vertical migration, 030304 developmental biology, 0105 earth and related environmental sciences, Marine biology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, Multidisciplinary, fungi, General Chemistry, Sea spray, Aerosol, Sea surface temperature, stomatognathic diseases, 13. Climate action, Environmental chemistry, Environmental science, Surface water
Abstract: Sea spray aerosol (SSA) formation have a major role in the climate system, but measurements at a global-scale of this micro-scale process are highly challenging. We measured high-resolution temporal patterns of SSA number concentration over the Atlantic Ocean, Caribbean Sea, and the Pacific Ocean covering over 42,000 km. We discovered a ubiquitous 24-hour rhythm to the SSA number concentration, with concentrations increasing after sunrise, remaining higher during the day, and returning to predawn values after sunset. The presence of dominating continental aerosol transport can mask the SSA cycle. We did not find significant links between the diel cycle of SSA number concentration and diel variations of surface winds, atmospheric physical properties, radiation, pollution, nor oceanic physical properties. However, the daily mean sea surface temperature positively correlated with the magnitude of the day-to-nighttime increase in SSA concentration. Parallel diel patterns in particle sizes were also detected in near-surface waters attributed to variations in the size of particles smaller than ~1 µm. These variations may point to microbial day-to-night modulation of bubble-bursting dynamics as a possible cause of the SSA cycle., Sea spray aerosol (SSA) are an important way through which oceans can influence the atmosphere’s radiative properties. Here, the authors present measurements taken over a 42,000 km ship cruise in the Atlantic and Pacific Ocean and show that SSA number concentrations vary over a 24-hour cycle, possibly linked to surface water bubble-bursting dynamics.
Published: 2021
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2. The characteristics of particulate absorption, scattering and attenuation coefficients in the surface ocean; Contribution of the Tara Oceans expedition

Author: Wayne H. Slade, Marc Picheral, Hervé Claustre, Gabriel Gorsky, Thomas Leeuw, Josephine Ras, Eric Karsenti, Alison Chase, Lisa Taylor, Emmanuel Boss, University of Maine, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Absorption spectroscopy, Mineralogy, Ocean Engineering, Aquatic Science, Oceanography, 01 natural sciences, Spectral line, 010309 optics, 0103 physical sciences, 14. Life underwater, Absorption (electromagnetic radiation), 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Chemistry, Scattering, Attenuation, Particulates, Particle attenuation coefficient, [SDU]Sciences of the Universe [physics], 13. Climate action, Ocean color, Bio-optics, Particle scattering coefficient, Satellite, Particle absorption coefficient
Abstract: International audience; A dataset consisting of AC-S measurements of (hyper-) spectral particulate absorption, scattering and attenuation coefficients were obtained from measurements performed on the flow-through system of the R/V Tara during its 2.5-year long expedition.The AC-S instruments were robust, working continuously with weekly maintenance for about 3 months at a time, and provided absorption (attenuation) data for 454 (375) days, or 90% (75%) of total possible days during the expedition.This dataset has been mapped to 1 km×1 km bins to avoid over emphasizing redundant data, and to match the spatial scale of typical ocean color satellite sensors. It consists of nearly 70,000 particulate absorption spectra and about 60,000 particulate scattering and attenuation spectra. These data are found to be consistent with chlorophyll extraction and with the published average shapes of particulate absorption and scattering spectra and bio-optical relationships. This dataset is richer than previous ones in the data from open-ocean (oligotrophic) environments making it more representative of global distributions and of utility for global algorithm development.
Published: 2013
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3. Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land

Author: Stéphanie Petit, Bruno Dumontet, Amanda Elineau, Gabriel Gorsky, Maria Luiza Pedrotti, Andrés Cózar, Elisa Martí, Stéphane Bruzaud, Jean Claude Crebassa, 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), Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), Expédition MED, Questembert, Department of Biology [Univ. of Cadiz], University of Cadiz, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Institut Brestois du Numérique et des Mathématiques (IBNM), and Université de Brest (UBO)-Université de Brest (UBO)-Université de Brest (UBO)
Subjects: Mediterranean climate, 010504 meteorology & atmospheric sciences, Polymers, lcsh:Medicine, Environmental pollution, 010501 environmental sciences, 01 natural sciences, Mediterranean sea, Abundance (ecology), Oceans, lcsh:Science, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, education.field_of_study, Multidisciplinary, Ecology, Plankton, Pollution, Chemistry, Macromolecules, Physical Sciences, Engineering and Technology, Plastics, Environmental Monitoring, Research Article, Environmental Engineering, Materials by Structure, Population, Materials Science, Bodies of water, Sea Water, Surface Water, Mediterranean Sea, Animals, 14. Life underwater, education, Materials by Attribute, 0105 earth and related environmental sciences, Hydrology, Water Pollution, lcsh:R, Organisms, Biology and Life Sciences, Polymer Chemistry, Debris, Invertebrates, Marine and aquatic sciences, Earth sciences, 13. Climate action, Environmental science, lcsh:Q, Plastic pollution, Environmental Pollution, Surface water
Abstract: International audience; The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (< 2 mm) was higher within the 1-km coastal water strip, suggesting a rapid fragmentation down along the shoreline, likely related with the washing ashore on the beaches. This study constitutes a first attempt to determine the impact of plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts.
Published: 2016
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4. In situ imaging reveals the biomass of giant protists in the global ocean

Author: Rainer Kiko, Fabrice Not, Helena Hauss, Nicolas Mayot, Gabriel Gorsky, Lionel Guidi, Marc Picheral, Lars Stemmann, Pieter Vandromme, Tristan Biard, Diversité et Interactions au sein du Plancton Océanique (DIPO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Biogeochemical cycle, Multidisciplinary, 010504 meteorology & atmospheric sciences, biology, Ecology, 010604 marine biology & hydrobiology, Rhizaria, Biota, Plankton, biology.organism_classification, 01 natural sciences, Zooplankton, 13. Climate action, Acantharia, Ecosystem, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Radiolaria, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: International audience; Planktonic organisms play crucial roles in oceanic food webs and global biogeochemical cycles1, 2. Most of our knowledge about the ecological impact of large zooplankton stems from research on abundant and robust crustaceans, and in particular copepods3, 4. A number of the other organisms that comprise planktonic communities are fragile, and therefore hard to sample and quantify, meaning that their abundances and effects on oceanic ecosystems are poorly understood. Here, using data from a worldwide in situ imaging survey of plankton larger than 600 μm, we show that a substantial part of the biomass of this size fraction consists of giant protists belonging to the Rhizaria, a super-group of mostly fragile unicellular marine organisms that includes the taxa Phaeodaria and Radiolaria (for example, orders Collodaria and Acantharia). Globally, we estimate that rhizarians in the top 200 m of world oceans represent a standing stock of 0.089 Pg carbon, equivalent to 5.2% of the total oceanic biota carbon reservoir5. In the vast oligotrophic intertropical open oceans, rhizarian biomass is estimated to be equivalent to that of all other mesozooplankton (plankton in the size range 0.2–20 mm). The photosymbiotic association of many rhizarians with microalgae may be an important factor in explaining their distribution. The previously overlooked importance of these giant protists across the widest ecosystem on the planet6 changes our understanding of marine planktonic ecosystems.
Published: 2016
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5. Impact of appendicularians on detritus and export fluxes: a model approach at DyFAMed site

Author: Léo Berline, Marcello Vichi, Gabriel Gorsky, Lars Stemmann, Fabien Lombard, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centro Euro-Mediterraneo per i Cambiamenti Climatici [Bologna] (CMCC), Oceanography Section, Technical University of Denmark [Lyngby] (DTU), INSU, 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)-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), and Danmarks Tekniske Universitet = Technical University of Denmark (DTU)
Subjects: 0106 biological sciences, chemistry.chemical_classification, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Ecology, 010604 marine biology & hydrobiology, Life Sciences, Pelagic zone, Aquatic Science, Plankton, 01 natural sciences, Zooplankton, Flux (metallurgy), Oceanography, chemistry, Grazing, Environmental science, Organic matter, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Pelagic ecosystem, 0105 earth and related environmental sciences
Abstract: International audience; So far, appendicularians role in the biogeochemical cycling of organic matter has been overlooked. Appendicularians represent only a fraction of total mesozooplankton biomass, however these ubiquitous zooplankters have very high filtration and growth rates compared to copepod, and produce numerous fecal pellets and filtering houses contributing to the export production by aggregating small marine particles. To study their quantitative impact on biogeochemical fluxes, we have included this group in the Biogeochemical Flux Model (BFM), using a recently developed ecophysiological model. One dimensional annual simulations of the pelagic ecosystem including appendicularians were conducted with realistic surface forcing for year 2000, using data from the DyFAMed open ocean station. The appendicularian grazing impact was generally low, but appendicularians increased detritus production by 8% and export production by 55% compared to a simulation without appendicularians. Therefore present biogeochemical models lacking appendicularians probably under, or misestimate the detritus and export production by omitting the pathway from small sized plankton to fast sinking detritus. Detritus production and export rates are 60% lower than estimates from mesotrophic sites, showing that appendicularians' role is lower but still significant in oligotrophic environments. The simulated annual export at 200 m exceeds sediment trap values by 44%, suggesting an intense degradation during the sinking of appendicularian detritus, supported by observations made in other sites. Thus degradation and grazing of appendicularians detritus need a better quantification if we are to accurately assess the appendicularian role in the export flux.
Published: 2010
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6. The Underwater Vision Profiler 5: An advanced instrument for high spatial resolution studies of particle size spectra and zooplankton

Author: Gabriel Gorsky, Marc Picheral, Ghizlaine Iddaoud, Lionel Guidi, David M. Karl, and Lars Stemmann
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Pixel, Underwater vision, 010604 marine biology & hydrobiology, Resolution (electron density), Flux, Ocean Engineering, Ranging, Mooring, 01 natural sciences, 14. Life underwater, Particle size, CTD, 0105 earth and related environmental sciences, Remote sensing
Abstract: The Underwater Vision Profiler (UVP) was developed to quantify the vertical distribution of macroscopic particles and zooplankton 100 mu m in size. The smaller size limit is fixed by optical resolution, whereas the larger size limit is determined by the volume of water illuminated per image. The new fifth generation instrument (UVP5) is compact (30 kg in air) and operates either as a stand-alone instrument with an independent power supply for use on a mooring or free-drifting array, or as a component of a Conductivity, Temperature, and Depth (CTD)-rosette package. Images are recorded at a frequency up to 6 Hz. If the UVP5 is interfaced with a CTD, these images are acquired and analyzed in real time. Images are recorded every 20 cm at the 1 m s(-1) lowering speed. The current maximum deployment depth is 3000 m. The recorded volume per image is 1.02 L, and the conversion equation from pixel area to size in mm(2) is S(m) = 0.003S(p)(1.3348) where S(p) is the surface of the particle in pixels and S(m) the surface in mm(2). Comparisons between the earlier UVP versions and UVP5 indicate that images ranging in size from 105 mu m to 2.66 mm are identical so historical and contemporary data sets can be compared.
Published: 2010
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7. Larvae of the pteropod Cavolinia inflexa exposed to aragonite undersaturation are viable but shell-less

Author: Samir Alliouane, Gabriel Gorsky, Jean-Pierre Gattuso, Steeve Comeau, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Mediterranean climate, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Zoology, Aquatic Science, engineering.material, Biology, 01 natural sciences, chemistry.chemical_compound, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, Evolution, Behavior and Systematics, Cavolinia inflexa, 0105 earth and related environmental sciences, Larva, Ecology, 010604 marine biology & hydrobiology, Aragonite, fungi, Ocean acidification, Food web, chemistry, engineering, Carbonate
Abstract: International audience; Larvae of the Mediterranean pteropod Cavolinia inflexa were maintained at controlled pH(T) values of 8.1, 7.82 and 7.51, equivalent, respectively, to pCO(2) levels of 380, 857 and 1,713 mu atm. At pH(T) 7.82, larvae exhibited malformations and lower shell growth, compared to the control condition. At pH(T) 7.51, the larvae did not make shells but were viable and showed a normal development. However, smaller shells or no shells will have both ecological (food web) and biogeochemical (export of carbon and carbonate) consequences. These results suggest that pteropod larvae, as well as the species dependent upon them or upon adults as a food resource, might be significantly impacted by ocean acidification.
Published: 2010
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8. Environmental characteristics of Agulhas rings affect interocean plankton transport

Author: Colomban de Vargas, Stefanie Kandels-Lewis, Gregory K. Farrant, Laurence Garczarek, Hiroyuki Ogata, Silvia G. Acinas, Pascal Hingamp, Shruti Malviya, Lucie Bittner, Bruno Blanke, Matthew B. Sullivan, Michael J. Follows, Sarah Searson, Patrick Wincker, Oliver Jahn, Emilie Villar, Cyrille Lepoivre, Jennifer R. Brum, Shinichi Sunagawa, Thomas Vannier, Lionel Guidi, Pierre Testor, Tara Oceans Coordinators, Hervé Le Goff, Chris Hill, Daniele Iudicone, Stéphane Audic, Sébastien Santini, Stephane Pesant, Adriana Zingone, Gabriel Gorsky, Fabrice Not, Nicolas Grima, Jean-Baptiste Romagnan, Céline Dimier, Atsuko Tanaka, Raffaella Casotti, Jean-Pierre Gattuso, Flora Vincent, John R. Dolan, Eric Pelletier, Alison Chase, Jean-Louis Jamet, Emmanuel Boss, Eleonora Scalco, Fabrizio D'Ortenzio, Peer Bork, Christophe Brunet, Marc Picheral, Sabrina Speich, Simon Roux, Chris Bowler, Eric Karsenti, Sarah M. Schwenck, Information génomique et structurale (IGS), Aix Marseille Université (AMU)-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), Massachusetts Institute of Technology (MIT), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-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 National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), University of Arizona, Stazione Zoologica Anton Dohrn (SZN), University of Maine, Observatoire océanologique de Villefranche-sur-mer (OOVM), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-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), Processus de Transfert et d'Echanges dans l'Environnement - EA 3819 (PROTEE), Université de Toulon (UTLN), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Développement Instrumental et Techniques Marines (DITM), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Génomique métabolique (UMR 8030), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Variabilité de l'Océan et de la Glace de mer (VOG), 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), European Molecular Biology Laboratory [Heidelberg] (EMBL), Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Max Delbrück Centre for Molecular Medicine, Data Publisher for Earth and Environmental Science (PANGAEA), University of Bremen, We appreciate the commitment of the following people and sponsors: CNRS (in particular, Groupement de Recherche GDR3280), European Molecular Biology Laboratory (EMBL), Genoscope/CEA, VIB, Stazione Zoologica Anton Dohrn, UNIMIB, Fund for Scientific Research–Flanders, Rega Institute, KU Leuven, the French Ministry of Research, the French government Investissements d’Avenir programmes OCEANOMICS (ANR-11-BTBR-0008), FRANCE GENOMIQUE (ANR-10-INBS-09-08), MEMO LIFE (ANR-10-LABX-54), PSL* Research University (ANR-11-IDEX-0001-02), and ANR (projects POSEIDON/ ANR-09-BLAN- 0348, PHYTBACK/ANR-2010-1709-01, PROMETHEUS/ANR-09-PCS-GENM-217, SAMOSA/ANR-13-ADAP0010, and TARAGIRUS/ANR-09-PCS-GENM-218), European Union FP7 (MicroB3/No.287589, IHMS/HEALTH-F4-2010-261376, and MaCuMBA/No.311975), ERC Advanced Grant Award to C.B. (Diatomite: 294823), Gordon and Betty Moore Foundation grant (no. 3790) to M.B.S., Spanish Ministry of Science and Innovation grant CGL2011-26848/BOS MicroOcean PANGENOMICS to S.G.A., TANIT (CONES 2010-0036) from the Agència de Gestió d´Ajusts Universitaris i Reserca to S.G.A., JSPS KAKENHI grant no. 26430184 to H.O., NASA Ocean Biology and Biogeochemistry program (NNX11AQ14G and NNX09AU43G) to E.B., The Italian Research for the Sea (Flagship Project RITMARE) to D.I., and FWO, BIO5, and Biosphere 2 to M.B.S. We also appreciate the support and commitment of Agnès b. and Etienne Bourgois, the Veolia Environment Foundation, Region Bretagne, Lorient Agglomeration, World Courier, Illumina, the EDF Foundation, FRB, the Prince Albert II de Monaco Foundation, and the Tara schooner and its captains and crew. We thank MERCATOR-CORIOLIS and ACRI-ST for providing daily satellite data during the expedition. We are also grateful to the French Ministry of Foreign Affairs for supporting the expedition and to the countries that graciously granted sampling permissions. Tara Oceans would not exist without continuous support from 23 institutes (http://oceans.taraexpeditions.org). We also acknowledge excellent assistance from the European Bioinformatics Institute (EBI), in particular G. Cochrane and P. ten Hoopen, as well as the EMBL Advanced Light Microscopy Facility (ALMF), in particular R. Pepperkok. We thank Y. Timsit for stimulating scientific discussions and critical help during writing of the manuscript. The altimeter products were produced by Ssalto/Duacs and CLS, with support from CNES., ANR-11-BTBR-0008,OCEANOMICS,Biotechnologies et bioressources pour la valorisation des écosystèmes marins planctoniques(2011), ANR-10-INBS-0009,France-Génomique,Organisation et montée en puissance d'une Infrastructure Nationale de Génomique(2010), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), ANR-09-BLAN-0348,POSEIDON(2009), ANR-10-BLAN-1709,PHYTBACK,Rétroactions écologie-climat dues à l'évolution de la taille et de la forme du phytoplancton(2010), ANR-13-ADAP-0010,SAMOSA,Synechococcus as a model genus for studying adaptation of marine phytoplankton to environmental changes(2013), European Project: 287589,EC:FP7:KBBE,FP7-OCEAN-2011,MICRO B3(2012), European Project: 261376,EC:FP7:HEALTH,FP7-HEALTH-2010-single-stage,IHMS(2011), European Project: 294823,EC:FP7:ERC,ERC-2011-ADG_20110310,DIATOMITE(2012), Adaptation et diversité en milieu marin (AD2M), 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)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0303 health sciences, Atlantic hurricane, Biogeochemical cycle, Multidisciplinary, 010504 meteorology & atmospheric sciences, Ocean current, fungi, Biology, Plankton, 01 natural sciences, 03 medical and health sciences, Indian ocean, Oceanography, Biological dispersal, Seawater, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Nitrogen cycle, 030304 developmental biology, 0105 earth and related environmental sciences
Abstract: Villar, Emilie ... et. al.-- 11 pages, 8 figures, supplementary materials www.sciencemag.org/content/348/6237/1261447/suppl/DC1, Agulhas rings provide the principal route for ocean waters to circulate from the Indo-Pacific to the Atlantic basin. Their influence on global ocean circulation is well known, but their role in plankton transport is largely unexplored. We show that, although the coarse taxonomic structure of plankton communities is continuous across the Agulhas choke point, South Atlantic plankton diversity is altered compared with Indian Ocean source populations. Modeling and in situ sampling of a young Agulhas ring indicate that strong vertical mixing drives complex nitrogen cycling, shaping community metabolism and biogeochemical signatures as the ring and associated plankton transit westward. The peculiar local environment inside Agulhas rings may provide a selective mechanism contributing to the limited dispersal of Indian Ocean plankton populations into the Atlantic. © 2015, American Association for the Advancement of Science. All rights reserved, We appreciate the commitment of the following people and sponsors: CNRS (in particular, Groupement de Recherche GDR3280); European Molecular Biology Laboratory (EMBL); Genoscope/CEA; VIB; Stazione Zoologica Anton Dohrn; UNIMIB; Fund for Scientific Research–Flanders; Rega Institute, KU Leuven; the French Ministry of Research; the French government Investissements d’Avenir programmes OCEANOMICS (ANR-11-BTBR-0008), FRANCE GENOMIQUE (ANR-10-INBS-09-08), MEMO LIFE (ANR-10-LABX-54), PSL* Research University (ANR-11-IDEX-0001-02), and ANR (projects POSEIDON/ ANR-09-BLAN- 0348, PHYTBACK/ANR-2010-1709-01, PROMETHEUS/ANR-09-PCS-GENM-217, SAMOSA/ANR-13-ADAP-0010, and TARAGIRUS/ANR-09-PCS-GENM-218); European Union FP7 (MicroB3/No.287589, IHMS/HEALTH-F4-2010-261376, and MaCuMBA/No.311975); ERC Advanced Grant Award to C.B. (Diatomite: 294823); Gordon and Betty Moore Foundation grant (no. 3790) to M.B.S.; Spanish Ministry of Science and Innovation grant CGL2011-26848/BOS MicroOcean PANGENOMICS to S.G.A.; TANIT (CONES 2010-0036) from the Agència de Gestió d´Ajusts Universitaris i Reserca to S.G.A.; JSPS KAKENHI grant no. 26430184 to H.O.; NASA Ocean Biology and Biogeochemistry program (NNX11AQ14G and NNX09AU43G) to E.B.; The Italian Research for the Sea (Flagship Project RITMARE) to D.I.; and FWO, BIO5, and Biosphere 2 to M.B.S.We also appreciate the support and commitment of Agnès b. and Etienne Bourgois, the Veolia Environment Foundation, Region Bretagne, Lorient Agglomeration, World Courier, Illumina, the EDF Foundation, FRB, the Prince Albert II de Monaco Foundation, and the Tara schooner and its captains and crew. We thank MERCATOR-CORIOLIS and ACRI-ST for providing daily satellite data during the expedition. We are also grateful to the French Ministry of Foreign Affairs for supporting the expedition and to the countries that graciously granted sampling permissions. Tara Oceans would not exist without continuous support from 23 institutes (http://oceans.taraexpeditions.org)
Published: 2015
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9. Comprehensive Model of Annual Plankton Succession Based on the Whole-Plankton Time Series Approach

Author: Jean-Louis Jamet, Lionel Guidi, Christian Sardet, Gabriel Gorsky, Marc Picheral, Louis Legendre, Jean-Baptiste Romagnan, Dominique Jamet, Laure Mousseau, Lars Stemmann, M.L. Pedrotti, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Processus de Transfert et d'Echanges dans l'Environnement - EA 3819 (PROTEE), Université de Toulon (UTLN), Laboratoire de Biologie du Développement de Villefranche sur mer (LBDV), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Food Chain, 010504 meteorology & atmospheric sciences, Population Dynamics, lcsh:Medicine, Ecological succession, Biology, Models, Biological, 01 natural sciences, Mediterranean sea, Water column, Phytoplankton, Mediterranean Sea, 14. Life underwater, lcsh:Science, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, Trophic level, Multidisciplinary, Community, Ecology, 010604 marine biology & hydrobiology, lcsh:R, fungi, Plankton, Flow Cytometry, lcsh:Q, Seasons, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, Research Article
Abstract: International audience; Ecological succession provides a widely accepted description of seasonal changes in phy-toplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes) and larger (i.e. macroplankton) organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish lar-vae, for which no consistent data were available). Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche) weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model) characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.
Published: 2015
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10. Annual microplankton cycles in Villefranche Bay, Ligurian Sea, NW Mediterranean

Author: Fernando Gómez, Gabriel Gorsky, Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Water transport, 010504 meteorology & atmospheric sciences, Ecology, biology, 010604 marine biology & hydrobiology, Aquatic Science, Spring bloom, biology.organism_classification, 01 natural sciences, Zooplankton, Mediterranean sea, Oceanography, Diatom, Phytoplankton, Environmental science, 14. Life underwater, Bloom, Bay, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences
Abstract: Abundance and composition of microplankton were studied over a period of 2 years at two depths in Villefranche Bay (Ligurian Sea, NW Mediterranean Sea). Diatoms dominated the microplankton in late spring and autumn, whereas dinoflagellates composed the major part of the microplankton in summer. The silicoflagellate Dictyocha fibula and the diatom Thalassionema frauenfeldii dominated in winter. Ciliates showed low variability throughout the year with the lowest abundance in February and an increase which coincided with the diatom maxima during autumn in both years. In 1998, the spring bloom (in May) was mainly composed of dinoflagellates near the surface and of diatoms in deeper layers. Subsurface diatom maxima were observed in August-September and November. In 1999, diatoms peaked in May both at the surface and at the depth of 50 m. They showed a strong maximum in October. Dinoflagellates and tintinnids showed maxima in early November. Comparisons with previous studies reveal that (i) changes in species composition have not been significant, (ii) the silicoflagellate's abundance is lower during the present study, (iii) the sequential spring bloom is composed of a pico-nanoplankton bloom in March and microphytoplankton in May, whereas in other western Mediterranean areas the spring microphytoplankton bloom is reported in February and March, (iv) high water transport through the Corsica channel coinciding with low or negative winter values of North Atlantic Oscillation (NAO) index are associated with the anomalous strong development of the spring diatom blooms in the Bay of Villefranche, whereas the usual trend is the lack of or weak development of the spring diatom bloom. This feature may determine the nature and the fate of primary production and the interannual variability in the relative importance of the microbial food web versus the microbial loop.
Published: 2003
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11. Large particulate matter in the Western Mediterranean

Author: Isabelle Taupier-Letage, Marc Picheral, Gabriel Gorsky, Louis Marie Prieur, and Lars Stemmann
Subjects: 0106 biological sciences, Mediterranean climate, Biogeochemical cycle, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Continental shelf, 010604 marine biology & hydrobiology, Mesoscale meteorology, Aquatic Science, Oceanography, 01 natural sciences, Mediterranean Basin, Mediterranean sea, Eddy, 13. Climate action, Submarine pipeline, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Geology, 0105 earth and related environmental sciences
Abstract: The relationship between mesoscale hydrodynamics and the distribution of large particulate matter (LPM, particles larger than 200 Am) in the first 1000 m of the Western Mediterranean basin was studied with a microprocessor-driven CTD-video package, the Underwater Video Profiler (UVP). Observations made during the last decade showed that, in late spring and summer, LPM concentration was high in the coastal part of the Western Mediterranean basin at the shelf break and near the continental slope (computed maximum: 149 A gCl 1 between 0 and 100 m near the Spanish coast of the Gibraltar Strait). LPM concentration decreased further offshore into the central Mediterranean Sea where, below 100 m, it remained uniformly low, ranging from 2 to 4 A gCl 1 . However, a strong variability was observed in the different mesoscale structures such as the Almeria–Oran jet in the Alboran Sea or the Algerian eddies. LPM concentration was up to one order of magnitude higher in fronts and eddies than in the adjacent oligotrophic Mediterranean waters (i.e. 35 vs. 8 A gCl 1 in the Alboran Sea or 16 vs. 3 A gCl 1 in a small shear cyclonic eddy). Our observations suggest that LPM spatial heterogeneity generated by the upper layer mesoscale hydrodynamics extends into deeper layers. Consequently, the superficial mesoscale dynamics may significantly contribute to the biogeochemical cycling between the upper and meso-pelagic layers. D 2002 Elsevier Science B.V. All rights reserved.
Published: 2002
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12. Diel variation in the vertical distribution of particulate matter (>0.15mm) in the NW Mediterranean Sea investigated with the Underwater Video Profiler

Author: Lars Stemmann, Gabriel Gorsky, Marc Picheral, 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), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Aquatic Science, Plankton, Particulates, Oceanography, 01 natural sciences, Zooplankton, Mediterranean sea, Water column, Dry weight, 13. Climate action, Phytoplankton, Environmental science, 14. Life underwater, Diel vertical migration, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Day/night variations in the size distribution of the particulate matter > 0.15 mm (PM) were studied in May 1995 during the DYNAPROC time-series cruise in the northwestern Mediterranean Sea. Data on vertical distributions of PM (>0.15 mm) and zooplankton were collected with the Underwater Video Profiler (UVP). The comparisons of the UVP data with plankton net data and POC data from water bottles indicated that more than 97% of the particles detected by the UVP were non-living particles (0.15 mm) and that the PM contributed 4-34% of the total dry weight measured on GF/F filters. Comparison of seven pairs of day and night vertical profiles performed during the cruise showed that in the upper 800 m, the mean size and the volume of particles was higher at night than during the day. During the night, the integrated volume of the Ph I increased on average by 32 +/- 20%. This increase corresponded to a shift of smaller size classes ( < 0.5 mm) towards the larger ones (> 0.5 mm). During the day, the pattern was reversed, and the quantity of PM > 0.5 mm decreased. During the study period, the standing stock of PM (60-800 m) decreased from 7.5 to less than 2gm(-2) but the diel variations persisted, except for two short periods in the superficial layer following a wind event. The cyclic feeding activity induced by the diel vertical migration of zooplankton could be the best candidate to explain the observed diel fluctuations in the size classes of PM in the water column. However, our results also suggest that in the upper layer additional driving forces such as the increase of the level of turbulence after a wind event or the modification of the zoo- and phytoplankton community can influence the PM temporal evolution. (C) 2000 Elsevier Science Ltd. All rights reserved.
Published: 2000
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13. Does eddy-eddy interaction control surface phytoplankton distribution and carbon export in the North Pacific Subtropical Gyre?

Author: Matthew J. Church, Kelvin J. Richards, Allison A. Fong, Zbigniew Kolber, Solange Duhamel, Scott C. Doney, Lars Stemmann, Ricardo M. Letelier, Gabriel Gorsky, Sasha Tozzi, Karin M. Björkman, David M. Karl, George A. Jackson, Lionel Guidi, Binglin Li, and Paulo H. R. Calil
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Mesoscale meteorology, Soil Science, Aquatic Science, Oceanography, Spatial distribution, 01 natural sciences, Geochemistry and Petrology, Ocean gyre, Downwelling, Phytoplankton, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Transect, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Paleontology, Forestry, Plankton, Geophysics, Eddy, 13. Climate action, Space and Planetary Science, Environmental science
Abstract: [1] In the North Pacific Subtropical Gyre (NPSG), the regular occurrence of summer phytoplankton blooms contributes to marine ecosystem productivity and the annual carbon export. The mechanisms underlying the formation, maintenance, and decay of these blooms remain largely unknown; nitrogen fixation, episodic vertical mixing of nutrients, and meso- (
Published: 2012
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14. Intercomparison of six Mediterranean zooplankton time series

Author: Ivona Marasović, Gabriel Gorsky, Ioanna Siokou-Frangou, Lars Stemmann, Olja Vidjak, Stéphane Gasparini, Ma Luz Fernandez De Puelles, Alessandra Conversi, Maria Grazia Mazzocchi, Léo Berline, Carmen García-Comas, Georgia Assimakopoulou, S. Fonda-Umani, Frédéric Ibanez, Soultana Zervoudaki, 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), European Project: 36081,SESAME, 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), Berline, L., Siokou Frangou, I., Marasović, I., Vidjak, O., Fernández, de Puelles Ma L. u. z., Mazzocchi, M. g., Assimakopoulou, G., Zervoudaki, S., Fonda, Serena, Conversi, A., Garcia Comas, C., Ibanez, F., Gasparini, S., Stemmann, L., and Gorsky, G.
Subjects: 0106 biological sciences, Mediterranean climate, Water mass, zooplankton time series, taxonomic groups, NAO, EA/WR, Mediterranean Sea, Balearic Sea, Ligurian Sea, Tyrrhenian Sea, Adriatic Sea, Aegean Sea, 010504 meteorology & atmospheric sciences, Aquatic Science, Oceanography, 01 natural sciences, Zooplankton, long time serie, Centro Oceanográfico de Baleares, Abundance (ecology), Phytoplankton, Intercomparison, 14. Life underwater, Medio Marino, 0105 earth and related environmental sciences, Trophic level, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, climate change impacts, Geology, zooplankton, long time series, 13. Climate action, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, time series, Hydrography, Eutrophication
Abstract: We analyzed and compared Mediterranean mesozooplankton time series spanning 1957–2006 from six coastal stations in the Balearic, Ligurian, Tyrrhenian, North and Middle Adriatic and Aegean Sea. Our analysis focused on fluctuations of major zooplankton taxonomic groups and their relation with environmental and climatic variability. Average seasonal cycles and interannual trends were derived. Stations spanned a large range of trophic status from oligotrophic to moderately eutrophic. Intra-station analyses showed (1) coherent multi-taxa trends off Villefranche sur mer that diverge from the previous results found at species level, (2) in Baleares, covariation of zooplankton and water masses as a consequence of the boundary hydrographic regime in the middle Western Mediterranean, (3) decrease in trophic status and abundance of some taxonomic groups off Naples, and (4) off Athens, an increase of zooplankton abundance and decrease in chlorophyll possibly caused by reduction of anthropogenic nutrient input, increase of microbial components, and more efficient grazing control on phytoplankton. (5) At basin scale, the analysis of temperature revealed significant positive correlations between Villefranche, Trieste and Naples for annual and/or winter average, and synchronous abrupt cooling and warming events centered in 1987 at the same three sites. After correction for multiple comparisons, we found no significant correlations between climate indices and local temperature or zooplankton abundance, nor between stations for zooplankton abundance, therefore we suggest that for these coastal stations local drivers (climatic, anthropogenic) are dominant and that the link between local and larger scale of climate should be investigated further if we are to understand zooplankton fluctuations, Sí
Published: 2012
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15. Zooplankton long-term changes in the NW Mediterranean Sea: Decadal periodicity forced by winter hydrographic conditions related to large-scale atmospheric changes?

Author: Stéphane Gasparini, Maria Grazia Mazzocchi, Gabriel Gorsky, Frédéric Ibanez, Marc Picheral, Lars Stemmann, Carmen García-Comas, Léo Berline, Open University of Catalonia [Barcelona], 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), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn (SZN), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Mediterranean climate, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Pelagic zone, 15. Life on land, Aquatic Science, Oceanography, 01 natural sciences, Zooplankton, Salinity, Mediterranean sea, 13. Climate action, North Atlantic oscillation, Phytoplankton, Environmental science, 14. Life underwater, Hydrography, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Copepod, chaetognath, decapod larva, siphonophore and jellyfish monthly abundances, from 1974 to 2003 at Point B (northwestern Mediterranean), were obtained with the ZooScan. Principal component analysis (PCA) was performed on zooplankton, and another PCA on local environment. Almost-decadal periods (1974-1982, 1983-1991, 1992-1999, and 2000-2003) were distinguished in the 1st PC of zooplankton, and that of local environment (1974-1980, 1981-1991, 1992-1998, and 1999-2003). The 1st PC of local environment was correlated with winter North Atlantic Oscillation (NAO) until early 19905. In early 1980s, all groups increased and the majority of the decade abundances were above the long-term average for most groups. In the 1990s, all decreased, and in early 2000s they increased. This synchrony suggests bottom-up control as main mechanism structuring these groups. The 1980s were characterized by low winter temperature and high salinity. We hypothesize that phytoplankton production was favored during that decade due to increased nutrient uprise to surface by strong winter vertical mixing. In the 1990s salinity decreased probably to the detriment of vertical mixing and carrying capacity of the system. These results stress the role of salinity as physical forcing on water-column stability, in the NW Mediterranean, and the importance of winter conditions to determine the state of pelagic ecosystems. (C) 2011 Elsevier B.V. All rights reserved.
Published: 2011
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16. Experimental and modeling evidence of appendicularian-ciliate interactions

Author: Damien Eloire, Fabien Lombard, Angélique Gobet, Gabriel Gorsky, Lars Stemmann, Antoine Sciandra, John R. Dolan, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Microbial Ecology, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-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), 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM)
Subjects: 0106 biological sciences, Mutualism (biology), Ciliate, Microbial food web, 010504 meteorology & atmospheric sciences, biology, Ecology, Ciliata, 010604 marine biology & hydrobiology, Parasitism, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Predation, Protozoa, Oikopleura dioica, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Interactions between appendicularians and ciliates were observed over the life span of Oikopleura dioica in laboratory cultures and clarified with the use of mathematical modeling and microscopic observations. Complex interactions including competition, parasitism, predation, and histophagy occurred simultaneously, resulting in apparent mutualism. The large ciliate Strombidium sp. entered the inlet filters of appendicularian houses (larger than 500 mm body size) by distorting the mesh. Once inside, Strombidium fed on particles concentrated on the filters. When appendicularians were larger than 900 mm, both the high flow rate in the buccal tube and their esophagus width allowed the ‘‘host’’ appendicularian to capture and ingest ciliates. Thus, ciliates seem to be sequentially competitors, then parasites or commensal in appendicularian houses, and finally prey for appendicularians. Appendicularian rates of somatic growth and reproduction were enhanced when ciliates were ingested. This additional food supply could be essential in oligotrophic environments. Reciprocally, appendicularians support higher ciliate growth rates, allowing ciliates to survive and grow in food-limited environments. Appendicularians thus modify the size spectrum of the microbial food web both by removing small organisms (0.2–30 mm) and enhancing the growth of mid-sized and large ciliates.
Published: 2010
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17. Appendicularian ecophysiology. II. Modeling nutrition, metabolism, growth and reproduction of the appendicularian Oikopleura dioica

Author: Antoine Sciandra, Fabien Lombard, Gabriel Gorsky, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Ecophysiology, Ecological niche, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, biology, Ecology, 010604 marine biology & hydrobiology, media_common.quotation_subject, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Zooplankton, Animal science, Pellet, Oikopleura dioica, Reproduction, Clearance rate, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, media_common
Abstract: A model has been developed to simulate the growth of an individual appendicularian (Oikopleura dioica) from egg to spawning. This model uses a new set of experimental data presented in a companion paper in this volume and estimates growth rates and generation times as well as clearance rates, house and fecal pellet production and reproductive capacity at different temperatures and food concentrations. According to the model outputs, the weight of a single house represents 11.5% of the individual's total weight, a lower value than previously estimated. The relative weight of one fecal pellet varies as a function of food concentration. The model also confirms that the minimum food concentration for growth is about 20–30 µg C l− 1 and that growth is maximal for a 100 µg C l− 1 feeding concentration. The limits of the growth optimum in relation to food concentration and temperature can be considered as a first description of the fundamental ecological niche of appendicularians. This model can be used both for predicting (1) the impact of in situ observed populations on the pico- and nanoseston and (2) the production of large aggregates. These two pieces of information are often needed for large-scale biogeochemical models.
Published: 2009
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18. Appendicularian ecophysiology I

Author: Gabriel Gorsky, Christopher Sainsbury, Antoine Sciandra, Florent Renaud, Fabien Lombard, 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), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Ecophysiology, Gonad, 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Assimilation (biology), Total body, Metabolism, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Concentration dependent, medicine.anatomical_structure, Animal science, Botany, medicine, Oikopleura dioica, Clearance rate, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Three aspects of the appendicularian O. dioica ' s ecophysiology were measured here: 1) morphological parameters over a wide range of appendicularian sizes, including mature animals in order to document the morphological characteristics inducing reproduction; 2) clearance rate and assimilation efficiency using feeding incubations with different algal concentrations and 3) the effect of food concentration on growth, mortality and reproduction. The relationship between the body carbon weight and the clearance rate follows a power function, with an exponent of 0.91 (± 0.07). The rate of particles retention increases with the food concentration following a Michaelis–Menten relationship (half-saturation constant = 151 ± 22 µg C l − 1 , maximum clearance rate = 12 ± 1 µg C µg C − 1 d − 1 ). The carbon assimilation efficiency decreases with the increasing food concentration. As a result, appendicularian growth which is limited in concentrations lower than 50 µg C l − 1 is saturated above 100 µg C l − 1 . In immature animals the gonad represents less than 30% of the body volume whereas in mature individuals, its volume varies between 50% and 87% (mean 63%) suggesting that gonad/total volume ratio can be used as indicator of the maturation stages. The gonad weight in mature animals represents 70.3 (± 4.6)% of the total body carbon weight. Two major maturity stages can explain the changes in energy allocation: i) the somatic growth, when less energy is invested in gonad growth when compared to the rest of the body and ii) the maturation phase where most of the assimilated matter is invested in gonad maturation. This process is rapid, lasting only few hours. For this reason we measured completely mature organisms that are generally not measured during the experimental work with appendicularians. In food-limited conditions, the gonad maturation process starts with smaller individuals and ends with smaller reproductive animals having the same gonad to total volume ratio than in unlimited food conditions. The results obtained in this study were used to model the life cycle of O. dioica (see Lombard, F., Sciandra, A. and Gorsky, G., 2009-this volume. Appendicularian ecophysiology. II. Modeling nutrition, metabolism, growth and reproduction of the appendicularian Oikopleura dioica .).
Published: 2009
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19. Impact of ocean acidification on a key Arctic pelagic mollusc (Limacina helicina)

Author: Jean-Pierre Gattuso, Jean-Louis Teyssié, Ross A. Jeffree, Gabriel Gorsky, Steeve Comeau, 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), and The publication of this article is financed by CNRS-INSU.
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, biology, Limacina retroversa, Ecology, 010604 marine biology & hydrobiology, Ocean acidification, Pelagic zone, Limacina helicina, biology.organism_classification, 01 natural sciences, Food web, Oceanography, Arctic, Helicina, 13. Climate action, [SDU]Sciences of the Universe [physics], Environmental science, Ecosystem, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: International audience; Abstract. Thecosome pteropods (shelled pelagic molluscs) can play an important role in the food web of various ecosystems and play a key role in the cycling of carbon and carbonate. Since they harbor an aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic CO2 emissions. The impact of changes in the carbonate chemistry was investigated on Limacina helicina, a key species of Arctic ecosystems. Pteropods were kept in culture under controlled pH conditions corresponding to pCO2 levels of 350 and 760 μatm. Calcification was estimated using a fluorochrome and the radioisotope 45Ca. It exhibits a 28% decrease at the pH value expected for 2100 compared to the present pH value. This result supports the concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource. A decline of their populations would likely cause dramatic changes to the structure, function and services of polar ecosystems.
Published: 2009
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20. Relationship between particle size distribution and flux in the mesopelagic zone

Author: George A. Jackson, Lionel Guidi, Lars Stemmann, Gabriel Gorsky, Juan Carlos Miquel, Marc Picheral, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Department of Oceanography [College Station], Texas A&M University [College Station], Marine Environment Laboratories [Monaco] (IAEA-MEL), International Atomic Energy Agency [Vienna] (IAEA), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Mass flux, 010504 meteorology & atmospheric sciences, Chemistry, 010604 marine biology & hydrobiology, Mineralogy, Aquatic Science, Sedimentation, Oceanography, 01 natural sciences, Settling, 13. Climate action, Particle-size distribution, Sediment trap, Particle, Photic zone, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Marine snow
Abstract: Large aggregates commonly named ``marine snow'' are difficult to collect and study because of their fragile nature, but they make up the largest fraction of vertical carbon flux in the ocean. Developments in imaging sensors and computer systems have facilitated the development of in situ image acquisition systems that can be used to produce profiles of aggregate size distribution and abundance. However, it is difficult to collect information on the different properties of particles, such as their composition, from in situ images. In this paper, we relate sediment trap data to particle size (d) distributions to estimate the vertical fluxes (F) of mass, particulate organic carbon (POC), particulate inorganic carbon (PIC) and particulate organic nitrogen (PON) using simple power relationships (F = Ad Mean aggregate fractal dimension of 2.3 and a size-dependent settling speed are determined from the flux estimations. We have used these relationships to map the distribution of mass flux along 180 degrees W in the equatorial Pacific. Similar mass fluxes below the euphotic zone have been reported along 150 degrees W for the same period with conventional sediment traps, supporting the accuracy of these relationships. The high spatial resolution of sedimentation processes studied in situ with the Underwater Video Profiler allowed us to undertake a detailed study of the role of physical processes in vertical fluxes. (c) 2008 Elsevier Ltd. All rights reserved.
Published: 2008
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21. Global zoogeography of fragile macrozooplankton in the upper 100-1000 m inferred from the underwater video profiler

Author: Marc Picheral, Gabriel Gorsky, Kevin Robert, Frédéric Ibanez, Fabien Lombard, Lionel Guidi, Lars Stemmann, Harriet Paterson, Aino Hosia, Marsh J. Youngbluth, 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), University of Bergen (UiB), The University of Western Australia (UWA), Texas A&M University System, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche [LOV], Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN], University of Bergen [UiB], and The University of Western Australia [UWA]
Subjects: 0106 biological sciences, Water mass, Gelatinous zooplankton, 010504 meteorology & atmospheric sciences, Ecology, biology, Mesopelagic zone, 010604 marine biology & hydrobiology, Front (oceanography), Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Zooplankton, Water column, Mediterranean sea, Zoogeography, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Stemmann, L., Youngbluth, M., Robert, K., Hosia, A., Picheral, M., Paterson, H., Ibanez, F., Guidi, L., Lombard, F., and Gorsky, G. 2008. Global zoogeography of fragile macrozooplankton in the upper 100–1000 m inferred from the underwater video profiler. – ICES Journal of Marine Science, 65: 433–442. Mesopelagic gelatinous zooplankton fauna are insufficiently known because of inappropriate and infrequent sampling, but may have important trophic roles. In situ imaging systems and undersea vehicles have been used to investigate their diversity, distribution, and abundance. The use of different platforms, however, restricts the comparison of data from different regions. Starting in 2001, the underwater video profiler (UVP) was deployed during 12 cruises in six oceanic regimes (Mediterranean Sea, North Atlantic shelves, Mid-Atlantic Ridge, tropical Pacific Ocean, eastern Indian Ocean, and Subantarctic Ocean) to determine the vertical distribution of organisms in the upper 1000 m. Nine oceanic regions were identified based on the hydrological properties of the water column. They correspond to nine of the biogeochemical provinces defined by Longhurst. In all, 21 morphotypes were recognized: sarcodines (eight groups), ctenophores (two groups), siphonophores, medusae (five groups), crustaceans (one group), chaetognaths, appendicularians, salps, and fish. The similarity in the community assemblages of zooplankton in the 100–1000 m layer was significantly greater within regions than between regions, in most cases. The regions with comparable composition were located in the North Atlantic with adjacent water masses, suggesting that the assemblages were either mixed by advective transport or that environmental conditions were similar in mesopelagic layers. The data suggest that the spatial structuring of mesopelagic macrozooplankton occurs on large scales (e.g. basin scales) but not necessarily on smaller scales (e.g. oceanic front).
Published: 2008
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22. Effects of frontal processes on marine aggregate dynamics and fluxes: An interannual study in a permanent geostrophic front (NW Mediterranean)

Author: Isabelle Taupier-Letage, Louis Marie Prieur, Gabriel Gorsky, Marc Picheral, Lionel Guidi, Lars Stemmann, Louis Legendre, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), Texas A&M University System, 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Nepheloid layer, Front (oceanography), Mesoscale meteorology, Aquatic Science, Oceanography, 01 natural sciences, Mediterranean sea, Settling, 14. Life underwater, Equivalent spherical diameter, Ecology, Evolution, Behavior and Systematics, Geostrophic wind, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Marine snow
Abstract: This study provides and discusses the spatial distributions of abundances and sizes of marine-snow aggregates across the Ligurian Sea frontal system. A cross-front transect was sampled 34 times between 1992 and 1996, using the Underwater Video Profiler (UVP). Atlantic Water flows parallel to the Ligurian coast in the NW Mediterranean Sea, where that current creates a quasi-permanent front that separates the central and coastal waters. The horizontal distribution of aggregates (> 150 mu m ESD, Equivalent Spherical Diameter) in the upper 1000 m shows two main features. First, the smaller aggregates (150 mu m 1 mm) are highest in and under the frontal zone, probably as a result of physical coagulation, and/or biological transformations. The seasonal intensity of large aggregate accumulations in and under the frontal structure seems to be more related to the autumn-winter increase in sub-mesoscale and mesoscale activity of the current flow than to the surface phytoplankton biomass. Interestingly, the horizontal distribution of aggregates is affected not only in the frontal zone (0-300 m depth), but also deeper down to 1000 m, probably as a consequence of rapid sinking or vertical transport. Results suggest that the settling of large aggregates under the frontal zone may limit the cross-slope transport of fine-grained particles by coagulation due to differential settling between the small particles suspended in the continental nepheloid layer and the large aggregates. This process, which takes place in sub-mesoscale zones (5-10 km wide), was also observed in one other front in the Western Mediterranean Sea. This led us to hypothesize that the impact of frontal processes on particle and aggregate dynamics might be generalized. Since fronts exist in many other coastal regions, the vertical fluxes at sub-mesoscale may have consequences for the transport of continental particles to the ocean's interior. (C) 2007 Elsevier B.V. All rights reserved.
Published: 2008
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23. RAPID Research on Automated Plankton Identification

Author: Phil F. Culverhouse, Allen Hansen, Qiao Hu, Gabriel Gorsky, Ángel López-Urrutia, Cynthia H. Pilskaln, Edward M. Riseman, Hans G. Dam, Philippe Grosjean, Michael E. Sieracki, Paul E. Utgoff, Mark C. Benfield, Xabier Irigoien, Cabell S. Davis, Howard Schultz, AZTI - Tecnalia, Bigelow Laboratory for Ocean Sciences, National Science Foundation [Arlington] (NSF), City University of Hong Kong [Hong Kong] (CUHK), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Oceanography, 010504 meteorology & atmospheric sciences, Computer science, 010604 marine biology & hydrobiology, 14. Life underwater, Permission, 01 natural sciences, Data science, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Author Posting. © Oceanography Society, 2007. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 20, 2 (2007): 172-187.
Published: 2007
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24. Vertical distribution of aggregates (> 110 mu m) and mesoscale activity in the northeastern Atlantic: Effects on the deep vertical export of surface carbon

Author: Lionel Guidi, Louis Legendre, Marc Picheral, Louis Marie Prieur, Lars Stemmann, Gabriel Gorsky, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Water flow, 010604 marine biology & hydrobiology, Mesoscale meteorology, Aquatic Science, Plankton, Oceanography, 01 natural sciences, Nutrient, Dry weight, 13. Climate action, Phytoplankton, Sediment trap, Environmental science, Seawater, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Spatial and temporal variability in the distribution of marine aggregates (> 110 mu m) was studied using underwater video profilers in an area off the Iberian Peninsula and Azores Islands dominated by mesoscale and submesocale hydrodynamics in winter, spring, and summer 2001. In the 0-200-m layer, aggregates were most abundant in spring (100-120 mg dry weight [dry wt] m(-3)) and lowest during summer and winter (1-10 mg dry wt (-3)). In the deeper layers,(down to 1,000 m), the seasonal pattern was different, with concentrations highest in spring and summer, and lowest in winter (e.g., at 800 in, 5-10 mg dry wt m(-3) in spring and summer; 1-5 mg dry wt m(-3) in winter). The seasonal change in the abundance of aggregates in the upper 1,000 m was consistent with changes in the composition and intensity of the particulate flux recorded in sediment traps and with seasonal changes in the surface phytoplankton community. In an area dominated by eddies, surface accumulation of aggregates and export down to 1,000 in occur at mesoscale distances (< 100 km). The occurrence of a rich aggregate layer may be related to mesoscale activity in water flow that drives nutrient inputs, phytoplankton production, and the formation of large aggregates. Such spatially constrained zones of massive export may be typical of frontal open-sea systems, and may have been missed by conventional sediment trap moorings, which cannot resolve export at this mesoscale level.
Published: 2007
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25. Influence of body mass, food concentration, temperature and filtering activity on the oxygen uptake of the appendicularian Oikopleura dioica

Author: Gabriel Gorsky, Fabien Lombard, Antoine Sciandra, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Agroécologie [Dijon], Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC), 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Ecology, biology, 010604 marine biology & hydrobiology, Thalassiosira pseudonana, Q10, chemistry.chemical_element, Aquatic Science, biology.organism_classification, 01 natural sciences, Oxygen, Isochrysis galbana, Animal science, chemistry, Respiration, Botany, Oikopleura dioica, Respiration rate, Clearance rate, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: In appendicularians, filtering activity is known to vary inversely with food concentra- tion. Here, we investigate the response of respiration rate to clearance rate (notably tail beating), which is minimum in anesthetized animals and maximum in conditions of food deprivation. Respira- tion of different size classes of the appendicularian Oikopleura dioica was measured at 15°C in 4 con- trasting situations: in (1) high (H) and (2) low (L) concentrations of a lyophilized mixture of Isochrysis galbana (haptophyceae), with Thalassiosira pseudonana (diatom) offered as food, (3) without food and (4) in the presence of an anaesthetic. Measurements of the oxygen consumption in H concentra- tion were repeated at 22°C to examine the effect of temperature on respiration. The weight-specific respiration measured in H, L, and no food conditions were not significantly different. The absence of an apparent relationship between the activities of filtration and respiration may be explained by the unusual high basal oxygen consumption measured in anaesthetized appendicularians (67% of the total respiration rate of active animals). Our results also suggest that the respiration rate of O. dioica was overestimated in past studies (1.6 to 2.0 times). Despite this, the respiration of O. dioica measured in this study is generally higher than the rates reported for other zooplankton species. The Q10 de- termined from the temperature-dependent oxygen consumption (2.3) was close to the earlier obser- vations.
Published: 2005
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26. Enumeration, measurement, and identification of net zooplankton samples using the ZOOSCAN digital imaging system

Author: Gabriel Gorsky, Philippe Grosjean, Caroline Warembourg, Marc Picheral, 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), 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Training set, 010504 meteorology & atmospheric sciences, Ecology, business.industry, 010604 marine biology & hydrobiology, Digital imaging, Pattern recognition, Aquatic Science, Biology, Oceanography, Net (mathematics), 01 natural sciences, Zooplankton, Discriminant vector, Identification (information), Size frequency, Enumeration, 14. Life underwater, Artificial intelligence, business, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Grosjean, P., Picheral, M., Warembourg, C., and Gorsky, G. 2004. Enumeration,measurement, and identiﬁcation of net zooplankton samples using the ZOOSCAN digitalimaging system. e ICES Journal of Marine Science, 61: 518e525.Identifying and counting zooplankton are labour-intensive and time-consuming processesthat are still performed manually. However, a new system, known as ZOOSCAN, has beendesigned for counting zooplankton net samples. We describe image-processing and theresults of (semi)-automatic identiﬁcation of taxa with various machine-learning methods.Each scan contains between 1500 and 2000 individuals !0.5 mm. We used two trainingsets of about 1000 objects each divided into 8 (simpliﬁed) and 29 groups (detailed),respectively. The new discriminant vector forest algorithm, which is one of the mosteﬃcient methods, discriminates between the organisms in the detailed training set with anaccuracy of 75% at a speed of 2000 items per second. A supplementary algorithm tagsobjects that the method classiﬁed with low accuracy (suspect items), such that they could bechecked by taxonomists. This complementary and interactive semi-automatic processcombines both computer speed and the ability to detect variations in proportions and greylevels with the human skills to discriminate animals on the basis of small details, such aspresence/absence or number of appendages. After this checking process, total accuracyincreases to between 80% and 85%. We discuss the potential of the system as a standard foridentiﬁcation, enumeration, and size frequency distribution of net-collected zooplankton.
Published: 2004
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27. A vertical model of particle size distributions and fluxes in the midwater column that includes biological and physical processes - Part II: application to a three year survey in the NW Mediterranean Sea

Author: Lars Stemmann, George A. Jackson, Gabriel Gorsky, 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 National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Mesopelagic zone, 010604 marine biology & hydrobiology, Mineralogy, Aquatic Science, Plankton, Oceanography, Atmospheric sciences, 01 natural sciences, Zooplankton, Settling, 13. Climate action, Particle-size distribution, Particle, Environmental science, 14. Life underwater, Particle size, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Marine snow
Abstract: The largest decrease in the particle vertical flux occurs in the mesopelagic zone where particles are transformed by biological and physical mechanisms. Particle size distributions provide important clues into those processes affecting particle transformations in this region. We have studied them using an inter-annual data set showing the evolution of particle size distributions between 100 and 1000 m, comparing them to results from a series of size-resolved models of particle dynamics that include physical coagulation and biological remineralization. The formulation that best fits the observations consists of a combination of settling, microbial activity and zooplankton feeding. The calculated particulate organic carbon losses to microbial activity and zooplankton feeding are consistent with independent estimates of these rates. The model shows that it is possible to predict the particle size distribution at 1000 m depth knowing the particle size distribution at 100 m depth and the rates of transformation in the mesopelagic. The mesozooplankton appears to be important in decreasing the high flux of large particles in the upper midwater zone, microbes becomes more important in the deeper midwater zone as zooplankton become rarer. The results suggest that the mesozooplankton have a much greater effect on particle flux than the macrozooplankton. Their importance requires the mesozooplankton to feed preferentially on large settling particles, probably using remote detection. The present work shows that using particle size spectra is a useful way to understand the transformation of the vertical flux of element in the midwater zone. However, most of the assumptions on particle properties and processes are based on surface studies and more data from the midwater zone are needed to confirm the hypotheses. The model allows us to formulate crucial questions regarding particle dynamics in the midwater zone. (C) 2004 Elsevier Ltd. All rights reserved.
Published: 2004
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28. Individual growth model for the appendicularian Oikopleura dioica

Author: Gabriel Gorsky, Franck Touratier, Francois Carlotti, Institut méditerranéen d'océanologie (MIO), and 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)
Subjects: 0106 biological sciences, Ecophysiology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Generation time, 010504 meteorology & atmospheric sciences, Ecology, biology, 010604 marine biology & hydrobiology, Growth model, Aquatic Science, biology.organism_classification, Atmospheric sciences, 01 natural sciences, Oikopleura dioica, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Food quality, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Production rate
Abstract: A model of individual growth simulating the development of the main compartments and processes involved in the ecophysiology of the appendicularian Oikopleura dioica is presented. O. dioica is one of the 5 most frequent larvacean species inhabiting European seas, and laboratory studies are available for comparison with model outputs. Individual growth and interactions with the external medium are described by state variables and fluxes of C and N, using the stoichiometric approach. Three forcing variables control the animal's growth: temperature, food quantity, and food quality (i.e. C:N ratio and size of particles). Model outputs are compared to experimental data to analyse (1) the effect of food quantity and quality on trunk length; (2) the influence of temperature on trunk length, generation time, respiration, excretion and house production rate; (3) the variability of the filtration rate under different conditions of temperature, food quantity and food quality. Results of the model are coherent with most observations, and validation of the model was successful.
Published: 2003
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29. A JGOFS investigation of plankton variability and trophic interactions in the central equatorial Pacific (EBENE)

Author: Gabriel Gorsky, Robert Le Borgne, Marc Picheral, Lars Stemmann, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Equator, Soil Science, chemistry.chemical_element, Aquatic Science, MATIERE ORGANIQUE PARTICULEE, Oceanography, 01 natural sciences, ABONDANCE, Carbon cycle, OCEAN, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Transect, DISTRIBUTION SPATIALE, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Marine snow, REPARTITION VERTICALE, Biomass (ecology), BIOMASSE, Ecology, 010604 marine biology & hydrobiology, Paleontology, Forestry, Particulates, Snow, GRANULOMETRIE, CARBONE, CIRCULATION OCEANIQUE, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, RELATION TROPHIQUE, PLANCTON, Carbon, Geology
Abstract: International audience; Marine snow ( MS) distribution from the surface to 1000 m depth was determined in the equatorial Pacific using the underwater video profiler during the Etude du Broutage en Zone Equatoriale cruise in fall 1996. The latitudinal transect was carried out at 17 stations along the 180degrees meridian from 8 degreesS to 8 degreesN during a cold phase of El Nino-Southern Oscillation. Higher MS concentrations were found below the equatorial zone than poleward. At the equator the estimated integrated MS carbon m(-2) in the upper kilometer was 5.7 g m(-2), while both southward and northward (between 1degrees and 8degrees) the mean integrated MS carbon was about 2.7 g. m(-2). In the upper 50 m the MS carbon was twofold lower than the combined carbon of autotrophic and heterotrophic protists and four times lower than the mesozooplankton carbon biomass, both measured concurrently during the cruise. Different water bodies had different MS content. The highest concentrations were found in the South Equatorial Current, the South Equatorial Counter Current, and the North Equatorial Countercurrent. Tropical waters at the south in the South Subsurface Countercurrents and the warm northern superficial waters had the lowest MS biomass. Mechanistically, a latitudinal ``conveyor belt'', a poleward divergence of upwelled waters that return to the equator after being downwelled at north and south convergent zones, may partially explain the vertical distribution of particulate matter observed during the studied period.
Published: 2003
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30. Physical-biological coupling in the Strait of Gibraltar

Author: Miguel Bruno, Gabriel Gorsky, Andrés Cózar, Fernando Gómez, L Striby, Francisco Jiménez-Gómez, Andreas Reul, Fidel Echevarría, Tarek Sarhan, Nicolás González, Marc Picheral, Juan M. Vargas, Jesús García Lafuente, Madeleine Goutx, Manuel Varela, Francisco Plaza, J. Alonso, Laura Prieto, Carlos M. García, Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Microbiologie Marine, Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Water mass, Pycnocline, 010504 meteorology & atmospheric sciences, Advection, 010604 marine biology & hydrobiology, Internal wave, Plankton, Oceanography, 01 natural sciences, 13. Climate action, Phytoplankton, Upwelling, 14. Life underwater, Geology, Mixing (physics), [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: This study presents a joint analysis of the distributions of some biogeochemical variables and their relation to the hydrodynamics of Gibraltar Strait. It is a synthesis paper that brings together many results obtained during CANIGO project. We show the role of hydrodynamics as a forcing agent for the plankton community structure in the Strait, with emphasis on the two physical processes that we propose as key factors for the coupling: interface position and oscillations, and mixing processes along the Strait. As a general pattern, autotrophic plankton biomass increases at the Strait from southwest to northeast, a tendency that coincides with a gradual elevation of the interface depth in the same direction. The different mechanisms of mixing that take place in the Strait are briefly reviewed: The occurrence of the internal hydraulic jump is an important mechanism of mixing constrained to the spring tide situations, but other processes such as the generation of arrested internal waves of wavelength around 1 km are proposed as a complementary mixing mechanism, particularly during neap tides situations. Both mechanisms, the elevation of the pycnocline and these mixing events, can enhance biological productivity and biomass accumulation on the northeastern sector of the Strait, since phytoplankton cells are there packaged in a water mass with sufficient light and nutrients and smaller advective velocity. There is a clear north-south difference in the biological response to these upwelling episodes in the eastern section, with high nutrient and low chlorophyll in the south and the opposite in the north. The deeper interface and the greater water speed are the proposed reasons for this lower nutrient uptake on the southeastern sector. Finally, the temporal scales of variation of the mixing events, the influence of its periodicity on the productivity of the area and the influence of these upwelling episodes in the nearest Alboran Sea are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.
Published: 2002
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31. Four-year study of large-particle vertical distribution (0-1000 m) in the NW Mediterranean in relation to hydrology, phytoplankton, and vertical flux

Author: Gabriel Gorsky, Marc Picheral, Juan-Carlos Miquel, Jean-Claude Marty, Lars Stemmann, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Hydrology, Mediterranean climate, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Stratification (water), 15. Life on land, Oceanography, Annual cycle, 01 natural sciences, Mediterranean sea, Flux (metallurgy), Dry weight, 13. Climate action, Phytoplankton, Environmental science, 14. Life underwater, Picoplankton, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: Data on large particles (LP; > 0.15 mm), phytoplankton communities, vertical fluxes, and hydrology were collected between January 1992 and June 1996 in the NW Mediterranean Sea, during DYFAMED, an interdisciplinary program part of JGOFS France. LP concentrations at the study sites were typical for values found in other open-ocean studies. LP temporal evolution showed an annual cycle. Concentrations were the highest in winter/spring (20-1201-1, 5280 mg m(-3)) and lowest in summer and autumn (0-201-1, 0.8-60 mg m(-3)). We estimated that LP accounted on average, for 2-30% of the total particulate (> 0.7 mum) dry weight (DW). LP temporal evolution between 0-200 m was correlated with total Chl a and facoxanthin (diatoms), and inversely correlated to zeaxanthin (cyanobacteria and prochlorophytes). Although diatoms were clearly associated to LP, prymnesiophytes were associated to the two highest accumulation of particles > 1 mm. The DW fraction of particle > 0.5 mm to total LP increased from 10% in regenerated systems dominated by picoplankton to 50% during spring blooms. LP concentrations in the upper 200 m were correlated to mass flux recorded in sediment trap at 200 and 1000m. We defined three main periods for LP downward export related to physical stratification. (1) The major LP export occurred in winter and may be affected by deep vertical mixing; (2) in spring, at the onset of the thermal stratification LP downward export decreased, although pulses of phytoplanktonic production may have enhanced LP sedimentation over short time scales; (3) during the summer stratification, the deep water was generally depleted in LP. (C) 2002 Elsevier Science Ltd. All rights reserved.
Published: 2002
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32. Small-scale temporal variations in biogeochemical features in the Strait of Gibraltar, Mediterranean side - the role of NACW and the interface oscillation

Author: Madeleine Goutx, Manuel Varela, Gabriel Gorsky, L Striby, Juan M. Vargas, Fernando Gómez, Jesús García-Lafuente, Nicolás González, Marc Picheral, Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Microbiologie Marine, Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Chlorophyll a, Pycnocline, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Aquatic Science, Plankton, Oceanography, 01 natural sciences, Zooplankton, chemistry.chemical_compound, chemistry, 13. Climate action, Diurnal cycle, Phytoplankton, Environmental science, 14. Life underwater, Eutrophication, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: On the Mediterranean side of the Strait of Gibraltar, the distribution of physical, chemical and biological variables Ž . temperature, salinity, nutrients, chlorophyll a, lipids, particles size and plankton abundance was examined. Sampling was carried out between the surface and 150 m at a fixed station over a 24-h time series. The patterns observed were related to the overlaying of different processes. The Atlantic-Mediterranean interface acts as a strong pycnocline and its vertical oscillation accounts for the gross distribution of nutrients, particles, and living biomass. Injection of North Atlantic Central Ž. Ž . Water NACW into the upper layer occurs at the sill each semidiurnal tidal cycle every 12 h . As a consequence, in the upper Atlantic layer the NACW was observed every 12 h in the trough of the interface oscillation, whereas Surface Atlantic Ž. Water SAW dominated in the crest at the fixed station. The initially nutrient-rich NACW was associated with eutrophic signatures such as high chlorophyll, large cells and low turbidity; The nutrient depleted SAW was associated with oligotrophic signatures such as low chlorophyll, small cells and high turbidity. The distribution of lipid biotracers at the Ž. depth of the chlorophyll maxima 10-40 m depicted a similar trend with abundant chloroplast lipids and a low lipolysis index in NACW-enriched waters, and a high lipolysis index and abundant zooplankton tracers in SAW especially at night. During the eastward advection of Atlantic water, the nutrient content of NACW is likely to be assimilated by phytoplankton. A scenario is proposed for explaining changes in phytoplankton maxima composition during the time series observations, taking into account the timing of the NACW injection at the sill, the diurnal cycle and zooplankton grazing. Although more studies over a longer temporal scale are necessary to validate this scenario, our observations show the scale of daily variations in the physicalrbiological coupling in the Strait and the implications for nutrient and matter exchanges between the Atlantic and Mediterranean. q 2001 Elsevier Science B.V. All rights reserved.
Published: 2001
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33. Zooplankton distribution in four western Norwegian fjords

Author: Gabriel Gorsky, Marc Picheral, M. Youngbluth, J.-M. Grisoni, P.R. Flood, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, education.field_of_study, Gelatinous zooplankton, geography, geography.geographical_feature_category, Periphylla periphylla, 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Fauna, Population, Fjord, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Crustacean, Zooplankton, Fishery, Chaetognatha, 14. Life underwater, education, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: A multi-instrumental array constructed in the Laboratoire d'Ecologie du Plancton Marin in Villefranche sur mer, France, named the Underwater Video Profiler (WP), was used to investigate the vertical distribution of zooplankton in four western Norwegian fjords in the summer 1996. Six distinct zoological groups were monitored. The fauna included: (a) small crustaceans (mainly copepods), (b) ctenophores (mainly lobates), (c) siphonophores (mainly physonects), (d) a scyphomedusa Periphylla periphylla, (e) chaetognaths and (f) appendicularians. The use of the non-disturbing video technique demonstrated that the distribution of large zooplankton is heterogeneous vertically and geographically. Furthermore, the abundance of non-migrating filter feeders in the deep basins of the fjords indicates that there is enough food (living and non-living particulate organic matter) to support their dietary needs. This adaptation may be considered as a strategy for survival in fjords. Specifically, living in dark, deep water reduces visual predation and population loss encountered in the upper layer due to advective processes. (C) 2000 Academic Press.
Published: 2000
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34. Use of the Underwater Video Profiler for the study of aggregate dynamics in the North Mediterranean

Author: Lars Stemmann, Marc Picheral, Gabriel Gorsky, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Continental shelf, 010604 marine biology & hydrobiology, Nepheloid layer, Front (oceanography), Aquatic Science, Oceanography, 01 natural sciences, Geostrophic current, Mediterranean sea, Water column, 13. Climate action, Submarine pipeline, 14. Life underwater, Underwater, Geology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: The Underwater Video Profiler is a vertically deployed survey system designed for the quantification of particles >280 mu m and of large zooplankton in the 0-1000 m water column. Light reflected by undisturbed target objects forms a dark-field image, which is recorded at 25 Hz frequency. The recorded images are automatically digitized and analysed. The results are expressed as abundance or size distributions and they can be converted to volume or mass units. The system can be configured as a multi-instrument array and can simultaneously acquire biological and physical data. From May 1994 to April 1995 a monthly survey was performed across a frontal structure associated to the North Ligurian geostrophic current. In winter and spring 1995 the front, as well as the offshore dispersion limit of particles, were located near to the coast. In contrast, during autumn 1994, its position was open sea and the terrestrial matter was dispersed far from the coast. The continuous presence of intermediate nepheloid layers along the continental slope indicates that different processes may supply and transport the particulate matter to deeper layers, from where it can be diffused into the basin. (C) 2000 Academic Press.
Published: 2000
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35. C AND N COMPOSITION OF SOME NORTHWESTERN MEDITERRANEAN ZOOPLANKTON AND MICRONEKTON SPECIES

Author: Robert Fenaux, Jacques Sardou, Gabriel Gorsky, Serge Dallot, Claude Carré, Isabelle Palazzoli, Station Zoologique de Villefranche, and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Mediterranean climate, Gelatinous zooplankton, Elemental composition, 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Aquatic Science, biology.organism_classification, 01 natural sciences, Zooplankton, Crustacean, Animal science, Dry weight, Botany, Composition (visual arts), Oikopleura dioica, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: 54 species of northwestern Mediterranean zooplankton and micronekton were analysed for elemental composition. Regression equations for nine species and four crustacean orders allow the estimation of C and N content as a function of dry weight and length. The mean C content as percentage of dry weight varied from 3% for the ctenophore Cestus veneris to 58.5 % for the appendicularian Oikopleura dioica. The lowest N content was in C. veneris (0.7%) and the highest was in O. longicauda (13.9%). We compared different methods of treating gelatinous zooplankton prior to weighing. A short fixation in Bouin's solution, followed by rinsing in distilled water, seemed not to alter the samples and to allow an easier handling of small gelatinous organisms. Appendicularians, chaetognaths, and the siphonophore Chelophyes appendiculata yielded higher values than those reported in the literature. The high C and N content of appendicularians may correspond to their energetic strategy. The values predicted from a general equation for some gelatinous zooplankton can yield an error of 200%.
Published: 1988
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36. BIOGENIC DEBRIS FROM THE PELAGIC TUNICATE, OIKOPLEURA-DIOICA, AND ITS ROLE IN THE VERTICAL TRANSPORT OF A TRANS-URANIUM ELEMENT

Author: Scott W. Fowler, Gabriel Gorsky, Nicholas S. Fisher, Station Zoologique de Villefranche, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Écologie du Plancton Marin (LEPM), 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), Marine Environment Laboratories [Monaco] (IAEA-MEL), International Atomic Energy Agency [Vienna] (IAEA), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, biology, Ecology, 010604 marine biology & hydrobiology, Pellets, Biogeochemistry, Pelagic zone, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Tunicate, Mediterranean sea, Animal science, Oikopleura dioica, Seawater, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: The accumulation and retention of 241Am by the pelagic tunicate Oikopleura dioica were examined using laboratory cultures and radiotracer methodology. Animals (i.e., trunks and tails) and discarded empty houses accumulated Am from seawater, giving volume/volume concentration factors of 59±8 and 10±1, respectively. The half-time for retention of Am in empty labelled houses transferred to non-contaminated seawater was 29 h; the retention half-time of Am in houses discarded by larvaceans feeding on Am-labelled diatoms was 219 h; the half-time of Am in fecal pellets produced by animals feeding on a monospecific diet of diatoms was 134 h, and 247 h for fecal pellets from animals fed a mixed diet. Approximately 30% of filtered cells remained in houses after the houses were discarded. Sinking rates of discarded houses and fecal pellets were found to vary with temperature and size, ranging from 26–157 m day−1 (house) and from 25–166 m day−1 (fecal pellets). The ubiquity and abundance of appendicularians, together with their prodigious production of houses (e.g., 10±2 houses day−1 at 17°C for each experimental animal) point to their potential significance in the vertical transport of Am, and probably other reactive metals, to intermediate depths in the ocean.
Published: 1984
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