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Start Over Author "Gabriel Gorsky" Topic [sdu.stu.oc]sciences of the universe [physics]/earth sciences/oceanography
32 results on '"Gabriel Gorsky"'

1. A global marine particle size distribution dataset obtained with the Underwater Vision Profiler 5

Author

Rainer Kiko, Marc Picheral, David Antoine, Marcel Babin, Léo Berline, Tristan Biard, Emmanuel Boss, Peter Brandt, Francois Carlotti, Svenja Christiansen, Laurent Coppola, Leandro de la Cruz, Emilie Diamond-Riquier, Xavier Durrieu de Madron, Amanda Elineau, Gabriel Gorsky, Lionel Guidi, Helena Hauss, Jean-Olivier Irisson, Lee Karp-Boss, Johannes Karstensen, Dong-gyun Kim, Rachel M. Lekanoff, Fabien Lombard, Rubens M. Lopes, Claudie Marec, Andrew M. P. McDonnell, Daniela Niemeyer, Margaux Noyon, Stephanie H. O'Daly, Mark D. Ohman, Jessica L. Pretty, Andreas Rogge, Sarah Searson, Masashi Shibata, Yuji Tanaka, Toste Tanhua, Jan Taucher, Emilia Trudnowska, Jessica S. Turner, Anya Waite, 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), Curtin University [Perth], Planning and Transport Research Centre (PATREC), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-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)

Subjects
General Earth and Planetary Sciences, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

Marine particles of different nature are found throughout the global ocean. The term “marine particles” describes detritus aggregates and fecal pellets as well as bacterioplankton, phytoplankton, zooplankton and nekton. Here, we present a global particle size distribution dataset obtained with several Underwater Vision Profiler 5 (UVP5) camera systems. Overall, within the 64 µm to about 50 mm size range covered by the UVP5, detrital particles are the most abundant component of all marine particles; thus, measurements of the particle size distribution with the UVP5 can yield important information on detrital particle dynamics. During deployment, which is possible down to 6000 m depth, the UVP5 images a volume of about 1 L at a frequency of 6 to 20 Hz. Each image is segmented in real time, and size measurements of particles are automatically stored. All UVP5 units used to generate the dataset presented here were inter-calibrated using a UVP5 high-definition unit as reference. Our consistent particle size distribution dataset contains 8805 vertical profiles collected between 19 June 2008 and 23 November 2020. All major ocean basins, as well as the Mediterranean Sea and the Baltic Sea, were sampled. A total of 19 % of all profiles had a maximum sampling depth shallower than 200 dbar, 38 % sampled at least the upper 1000 dbar depth range and 11 % went down to at least 3000 dbar depth. First analysis of the particle size distribution dataset shows that particle abundance is found to be high at high latitudes and in coastal areas where surface productivity or continental inputs are elevated. The lowest values are found in the deep ocean and in the oceanic gyres. Our dataset should be valuable for more in-depth studies that focus on the analysis of regional, temporal and global patterns of particle size distribution and flux as well as for the development and adjustment of regional and global biogeochemical models. The marine particle size distribution dataset (Kiko et al., 2021) is available at https://doi.org/10.1594/PANGAEA.924375.

Published
2022
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2. An Integrative Assessment of the Plastic Debris Load in the Mediterranean Sea

Author

Maria Luiza Pedrotti, Fabien Lombard, Alberto Baudena, François Galgani, Amanda Elineau, Stephanie Petit, Maryvonne Henry, Romain Troublé, Gilles Reverdin, Enrico Ser-Giacomi, Mikaël Kedzierski, Emmanuel Boss, 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), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Processus et interactions de fine échelle océanique (PROTEO), 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)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-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)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Massachusetts Institute of Technology (MIT), Institut de Recherche Dupuy de Lôme (IRDL), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), and University of Maine

Subjects
Waste Products, Sea surface, History, Environmental Engineering, Polymers and Plastics, Microplastic, Pollution, Plastic debris, Industrial and Manufacturing Engineering, TARA Mediterranean expedition, Mediterranean Sea, Environmental Chemistry, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Business and International Management, Environmental Pollution, Plastics, Waste Management and Disposal, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, ZooScan, Environmental Monitoring
Abstract

International audience; The Mediterranean Sea is recognized as one of the most polluted areas by floating plastics. During the Tara Mediterranean expedition, an extensive sampling of plastic debris was conducted in seven ecoregions, from Gibraltar to Lebanon with the aim of providing reliable estimates of regional differences in floating plastic loads and plastic characteristics. The abundance, size, surface, circularity and mass of 75,030 pieces were analyzed and classified in a standardized multi-parameter database. Their average abundance was 2.60 × 105 items km−2 (2.25 × 103 to 8.50 × 106 km−2) resulting in an estimate of about 650 billion plastic particles floating on the surface of the Mediterranean. This corresponds to an average of 660 metric tons of plastic, at the lower end of literature estimates. High concentrations of plastic were observed in the northwestern coastal regions, north of the Tyrrhenian Sea, but also off the western and central Mediterranean basins. The Levantine basin south of Cyprus had the lowest concentrations. A Lagrangian Plastic Pollution Index (LPPI) predicting the concentration of plastic debris was validated using the spatial resolution of the data. The advanced state of plastic degradation detected in the analyses led to the conclusion that stranding/fragmentation/resuspension is the key process in the dynamics of floating plastic in Mediterranean surface waters. This is supported by the significant correlation between pollution sources and areas of high plastic concentration obtained by the LPPI.

Published
2022
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3. Marine DNA Viral Macro- and Microdiversity from Pole to Pole

Author

Ann C. Gregory, Ahmed A. Zayed, Nádia Conceição-Neto, Ben Temperton, Ben Bolduc, Adriana Alberti, Mathieu Ardyna, Ksenia Arkhipova, Margaux Carmichael, Corinne Cruaud, Céline Dimier, Guillermo Domínguez-Huerta, Joannie Ferland, Stefanie Kandels, Yunxiao Liu, Claudie Marec, Stéphane Pesant, Marc Picheral, Sergey Pisarev, Julie Poulain, Jean-Éric Tremblay, Dean Vik, Marcel Babin, Chris Bowler, Alexander I. Culley, Colomban de Vargas, Bas E. Dutilh, Daniele Iudicone, Lee Karp-Boss, Simon Roux, Shinichi Sunagawa, Patrick Wincker, Matthew B. Sullivan, Silvia G. Acinas, Peer Bork, Emmanuel Boss, Guy Cochrane, Michael Follows, Gabriel Gorsky, Nigel Grimsley, Lionel Guidi, Pascal Hingamp, Olivier Jaillon, Stefanie Kandels-Lewis, Eric Karsenti, Fabrice Not, Hiroyuki Ogata, Nicole Poulton, Jeroen Raes, Christian Sardet, Sabrina Speich, Lars Stemmann, University of Exeter, Institut de Génomique d'Evry (IG), Institut de Biologie François JACOB (JACOB), 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)-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 Paris-Saclay, 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), Utrecht University [Utrecht], 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), 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), Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Université Laval [Québec] (ULaval), 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), European Molecular Biology Laboratory [Grenoble] (EMBL), Ohio State University [Columbus] (OSU), Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Maine, Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (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 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)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Wellcome Trust Genome Campus, Evolution des Protistes et Ecosystèmes Pélagiques (EPEP), 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), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Biologie intégrative des organismes marins (BIOM), Observatoire océanologique de Banyuls (OOB), Stazione Zoologica Anton Dohrn (SZN), 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)-Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE), European Molecular Biology Laboratory [Heidelberg] (EMBL), Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Pangea, Bigelow Laboratory for Ocean Sciences, Rega Institute - VIB Center for the Biology of Disease, Department of Microbiology and Immunology, Bioinformatics and (eco-)systems Biology Laboratory, Louvain, Belgique, Université Catholique de Louvain = Catholic University of Louvain (UCL), Laboratoire de Biologie du Développement de Villefranche sur mer (LBDV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), 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), University of Arizona, Région Bretagne, Veolia Foundation, Fondation Prince Albert II de Monaco, Centre National de la Recherche Scientifique (France), Institut de biologie de l'ENS Paris (IBENS), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-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), 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), Université Paris-Saclay-Institut de Biologie François JACOB (JACOB), Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), 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), Adaptation et diversité en milieu marin (ADMM), and Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR)

Subjects
Aquatic Organisms, [SDV]Life Sciences [q-bio], Coronacrisis-Taverne, species, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, marine biology, [SDV.BID]Life Sciences [q-bio]/Biodiversity, Biology, General Biochemistry, Genetics and Molecular Biology, diversity gradients, Article, 03 medical and health sciences, 0302 clinical medicine, Tumours of the digestive tract Radboud Institute for Molecular Life Sciences [Radboudumc 14], Humans, Human virome, Ecosystem, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, Marine biology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, metagenomics, Drowning, Community, Ecology, Microbiota, DNA Viruses, Biodiversity, DNA, Population ecology, Biodiversity hotspot, Arctic, 13. Climate action, Metagenomics, [SDU]Sciences of the Universe [physics], population ecology, DNA, Viral, Viruses, Metagenome, Water Microbiology, 030217 neurology & neurosurgery, community ecology, geographic locations
Abstract

15 pages, 15 figures, 1 tables, supporting information https://doi.org/10.1016/j.cell.2019.03.040, Microbes drive most ecosystems and are modulated by viruses that impact their lifespan, gene flow, and metabolic outputs. However, ecosystem-level impacts of viral community diversity remain difficult to assess due to classification issues and few reference genomes. Here, we establish an ∼12-fold expanded global ocean DNA virome dataset of 195,728 viral populations, now including the Arctic Ocean, and validate that these populations form discrete genotypic clusters. Meta-community analyses revealed five ecological zones throughout the global ocean, including two distinct Arctic regions. Across the zones, local and global patterns and drivers in viral community diversity were established for both macrodiversity (inter-population diversity) and microdiversity (intra-population genetic variation). These patterns sometimes, but not always, paralleled those from macro-organisms and revealed temperate and tropical surface waters and the Arctic as biodiversity hotspots and mechanistic hypotheses to explain them. Such further understanding of ocean viruses is critical for broader inclusion in ecosystem models, Tara Oceans (that includes both the Tara Oceans and Tara Oceans Polar Circle expeditions) would not exist without the leadership of the Tara Expeditions Foundation and the continuous support of 23 institutes (https://oceans.taraexpeditions.org). We further thank the commitment of the following sponsors: CNRS (in particular Groupement de Recherche GDR3280 and the Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans-GOSEE), European Molecular Biology Laboratory (EMBL), Genoscope/CEA, The French Ministry of Research, and 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), and PSL∗ Research University (ANR-11-IDEX-0001-02). We also thank the support and commitment of Agnès b. and Etienne Bourgois, the Prince Albert II de Monaco Foundation, the Veolia Foundation, Region Bretagne, Lorient Agglomeration, Serge Ferrari, Worldcourier, and KAUST

Published
2019
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4. Gene Expression Changes and Community Turnover Differentially Shape the Global Ocean Metatranscriptome

Author

Guillem Salazar, Lucas Paoli, Adriana Alberti, Jaime Huerta-Cepas, Hans-Joachim Ruscheweyh, Miguelangel Cuenca, Christopher M. Field, Luis Pedro Coelho, Corinne Cruaud, Stefan Engelen, Ann C. Gregory, Karine Labadie, Claudie Marec, Eric Pelletier, Marta Royo-Llonch, Simon Roux, Pablo Sánchez, Hideya Uehara, Ahmed A. Zayed, Georg Zeller, Margaux Carmichael, Céline Dimier, Joannie Ferland, Stefanie Kandels, Marc Picheral, Sergey Pisarev, Julie Poulain, Silvia G. Acinas, Marcel Babin, Peer Bork, Chris Bowler, Colomban de Vargas, Lionel Guidi, Pascal Hingamp, Daniele Iudicone, Lee Karp-Boss, Eric Karsenti, Hiroyuki Ogata, Stephane Pesant, Sabrina Speich, Matthew B. Sullivan, Patrick Wincker, Shinichi Sunagawa, Emmanuel Boss, Guy Cochrane, Michael Follows, Gabriel Gorsky, Nigel Grimsley, Olivier Jaillon, Stefanie Kandels-Lewis, Fabrice Not, Nicole Poulton, Jeroen Raes, Christian Sardet, Lars Stemmann, European Commission, Ministerio de Economía y Competitividad (España), Institut de Biologie François JACOB (JACOB), 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), 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), Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), 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), Instituto de Fisica [Mexico] (UASLP), Universidad Autonoma de San Luis Potosi [México] (UASLP), Institute of Microbiology and Swiss Institute of Bioinformatics, CNS, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Center for Genomic Regulation (CRG-UPF), CIBER de Epidemiología y Salud Pública (CIBERESP), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), European Molecular Biology Laboratory [Heidelberg] (EMBL), Bayer Cropscience, Immunobiologie Cellulaire et Moléculaire des Infections Parasitaires, Université Pierre et Marie Curie - Paris 6 (UPMC)-IFR113-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Ohio State University [Columbus] (OSU), Institut de Chimie de Clermont-Ferrand - Clermont Auvergne (ICCF), Sigma CLERMONT (Sigma CLERMONT)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), European Molecular Biology Laboratory [Grenoble] (EMBL), 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), Takuvik Joint ULaval/CNRS Laboratory, Centre National de la Recherche Scientifique (CNRS)-Laval University [Québec], Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de Génomique d'Evry (IG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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 Paris-Saclay, Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), University of Maine, European Molecular Biology Laboratory European Bioinformatics Institute, Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), 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), Biologie intégrative des organismes marins (BIOM), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Sezione Ecologia Marina Integrata, Stazione Zoologica Anton Dohrn (SZN), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Information génomique et structurale (IGS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, Bigelow Laboratory for Ocean Sciences, Department of Bioscience Engineering, Vrije Universiteit Brussel (VUB), Laboratoire de Biologie du Développement de Villefranche sur mer (LBDV), 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)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Laboratoire de physique des océans (LPO), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), 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), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Université Paris-Saclay, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Kyoto University, Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Kyoto University [Kyoto], Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), and Centre National de la Recherche Scientifique (CNRS)-Université Laval [Québec] (ULaval)

Subjects
ASSEMBLY PROCESSES, Effects of global warming on oceans, DIVERSITY, microbial ecology, global ocean microbiome, CARBON, 0302 clinical medicine, biogeochemistry, Gene expression, ComputingMilieux_MISCELLANEOUS, 0303 health sciences, CLIMATE-CHANGE, Geography, Microbiota, Temperature, CYANOBACTERIA, [SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], GENOME, BACTERIA, community turnover, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, SURFACE, Oceans and Seas, Tara Oceans, Biology, Article, metagenome, General Biochemistry, Genetics and Molecular Biology, ocean warming, 03 medical and health sciences, eco-systems biology, Microbial ecology, [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN], metatranscriptome, Seawater, RNA, Messenger, 14. Life underwater, Gene, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, Science & Technology, Biogeochemistry, Molecular Sequence Annotation, Cell Biology, Environmental variation, Gene Expression Regulation, Cardiovascular and Metabolic Diseases, 13. Climate action, Metagenomics, Evolutionary biology, BIODIVERSITY, sense organs, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Transcriptome, 030217 neurology & neurosurgery, gene expression change, BIOGEOGRAPHY
Abstract

This article is contribution number 94 of Tara Oceans.-- 37 pages, 20 figures, 1 table, supplementary information https://doi.org/10.1016/j.cell.2019.10.014.-- All raw reads are available through ENA at https://www.ebi.ac.uk/ena using the identifiers listed in https://doi.org/10.5281/zenodo.3473199. Processed data are accessible at https://www.ebi.ac.uk/biostudies/studies/S-BSST297, and additional information is provided in https://doi.org/10.5281/zenodo.3473199 and at the companion website: https://www.ocean-microbiome.org. Scripts used in this manuscript are available through a Github repository at https://github.com/SushiLab/omrgc_v2_scripts, Ocean microbial communities strongly influence the biogeochemistry, food webs, and climate of our planet. Despite recent advances in understanding their taxonomic and genomic compositions, little is known about how their transcriptomes vary globally. Here, we present a dataset of 187 metatranscriptomes and 370 metagenomes from 126 globally distributed sampling stations and establish a resource of 47 million genes to study community-level transcriptomes across depth layers from pole-to-pole. We examine gene expression changes and community turnover as the underlying mechanisms shaping community transcriptomes along these axes of environmental variation and show how their individual contributions differ for multiple biogeochemically relevant processes. Furthermore, we find the relative contribution of gene expression changes to be significantly lower in polar than in non-polar waters and hypothesize that in polar regions, alterations in community activity in response to ocean warming will be driven more strongly by changes in organismal composition than by gene regulatory mechanisms, Tara Oceans (that includes both the Tara Oceans and Tara Oceans Polar Circle expeditions) would not exist without the leadership of the Tara Expeditions Foundation and the continuous support of 23 institutes (https://oceans.taraexpeditions.org). We further thank the commitment of the following sponsors: CNRS (in particular Groupement de Recherche GDR3280 and the Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans-GOSEE); European Molecular Biology Laboratory (EMBL); Genoscope/CEA; 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), and PSL∗ Research University (ANR-11-IDEX-0001-02); Gordon and Betty Moore Foundation (award 3790); the US National Science Foundation (OCE#1536989 and OCE#1829831 to M.B.S.); the European Union’s Horizon 2020 research and innovation programme (grant agreement 686070); and the Ohio Supercomputer and the EMBL and ETH Zürich HPC facilities for computational support. Funding for the collection and processing of the TARA data set was provided by NASA Ocean Biology and Biogeochemistry program under grants NNX11AQ14G, NNX09AU43G, NNX13AE58G, and NNX15AC08G to the University of Maine and Canada Excellence Research Chair on Remote sensing of Canada’s new Arctic frontier Canada Foundation for Innovation. C.B. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement 835067). S.G.A. thanks the Spanish Ministry of Economy and Competitiveness (CTM2017-87736-R). S. Sunagawa. is supported by the ETH and the Helmut Horten Foundation and by funding from the Swiss National Foundation (205321_184955)

Published
2019
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5. 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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6. 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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7. 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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8. Individual shrinking to enhance population survival: quantifying the reproductive and metabolic expenditures of a starving jellyfish, Pelagia noctiluca

Author

Fabien Lombard, Martin K. S. Lilley, Amanda Elineau, Lars Stemmann, Martina Ferraris, Alain Thiéry, 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), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), 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 Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, education.field_of_study, Jellyfish, Ecology, 010604 marine biology & hydrobiology, Population, Aquatic Science, Biology, Pelagia noctiluca, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Queen (playing card), biology.animal, 14. Life underwater, education, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

The holoplanktonic jellyfish Pelagia noctiluca is renowned for periods of high abundance, causing considerable problems to tourism and aquaculture. Little is understood about the drivers of its periodic presence and absence or how it survives unfavourable periods. Studying the effect of starvation, we evaluated the main metabolic expenses (reproduction, respiration and excretion) during those periods. P. noctiluca could shrink in size, losing up to 85% of their mass (6.6-7.1% loss day(-1)), while continuing to release eggs quasi-daily over a 28-day period. Egg production was proportional to size (mean 759 eggs day(-1) at 6 cm bell diameter), with up to 19 526 eggs released in a single spawn, thereby providing huge potential for population growth despite undergoing starvation. Small food rations decreased the rate of shrinking to 3.1% day(-1), prolonging life (49 days), potentially enhancing the chances of encountering more prey and regrowing. Metabolism increased with wet mass (allometric exponent: 0.93 for respiration, 0.82 for ammonium), however reproduction was the greatest carbon expenditure for individuals larger than 9 cm bell diameter. Temperature (9-29 degrees C) also significantly increased both respiration and, to a greater extent, excretion (Q(10) = 2.25 and 4.76). Consequentially a warming ocean may negatively affect survival rates unless prey abundance balances the increased metabolic demands.

Published
2014
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9. Culture and growth of the jellyfish Pelagia noctiluca in the laboratory

Author

Alain Thiéry, Martin K. S. Lilley, Amanda Elineau, Laurent Gilletta, Fabien Lombard, Léo Berline, Gabriel Gorsky, Perrine Cuvilliers, Martina Ferraris, 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 des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire de Biologie du Développement de Villefranche sur mer (LBDV), 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 de biodiversité et d'écologie marine et continentale (IMBE), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), 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), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS)

Subjects
Larva, Jellyfish, Ecology, biology, Aquatic Science, biology.organism_classification, Pelagia noctiluca, Zooplankton, Predation, Animal science, biology.animal, Basal metabolic rate, 14. Life underwater, Planula, Sea urchin, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; Four cohorts of the scyphozoan jellyfish Pelagia noctiluca were grown in the laboratory. For the first time, P. noctiluca was grown from eggs through to reproductive adults. The maximum life span in the laboratory was 17 mo. Pelagia noctiluca were first observed to release gametes at an umbrella diameter of 2.4 cm. Laboratory growth under steady feeding conditions showed initial growth followed by stagnation until dietary conditions were altered. A mismatch between the availability of optimal food and the presence of developmental stages may significantly increase the mortality rates of the young stages. Non-motile prey improved survival of ephyrae stages compared with zooplankton, but good survival and ephyrae growth were only obtained with a high-energy sea urchin egg diet. Maximal growth rates were up to 30% d(-1) for young ephyrae and 1.5-4% d(-1) for adults. Maximal growth rates were comparable between laboratory and in situ growth observations in the Ligurian Sea during 1969 and 2013. Combining observations would suggest that 230 d of continuous growth are required to reach the largest mean size observed in the wild (June 2013, mean +/- SD = 15.6 +/- 2.8 cm, range = 12-21 cm). We suggest that 90-120 d of continuous growth from planula larvae would yield reproductive individuals under ideal growing conditions. We discuss the daily prey abundances required by each individual to sustain basal metabolism and the observed growth rates.

Published
2014
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10. 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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11. 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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12. 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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13. 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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14. 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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15. 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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16. 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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17. 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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18. 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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19. 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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20. 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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21. 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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22. 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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23. 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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24. 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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25. 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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26. Miniature genome in the marine chordate Oikopleura dioica

Author

Alfred Beck, Daniel Chourrout, Eric M. Thompson, Michael Kube, Hee-Chan Seo, Marit Flo Jensen, Richard Reinhardt, Rolf B. Edvardsen, Hans Lehrach, Gabriel Gorsky, Endy Spriet, 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), Department of rheumatology and clinical immunology, Humboldt-Universität zu Berlin-Charité - UniversitätsMedizin = Charité - University Hospital [Berlin], 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 Humboldt University Of Berlin-Charité - UniversitätsMedizin = Charité - University Hospital [Berlin]

Subjects
0106 biological sciences, Male, Chromosomes, Artificial, Bacterial, DNA, Complementary, Repetitive Sequences, Chordate, 010603 evolutionary biology, 01 natural sciences, Genome, 03 medical and health sciences, Animals, 14. Life underwater, Urochordata, Cloning, Molecular, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, Repetitive Sequences, Nucleic Acid, Expressed Sequence Tags, 0303 health sciences, Multidisciplinary, biology, Anatomy, Sequence Analysis, DNA, biology.organism_classification, Spermatozoa, Introns, Ciona intestinalis, Genes, Evolutionary biology, Oikopleura dioica, DNA, Intergenic
Abstract

Oikopleura dioica is a small pelagic chordate belonging to the class of larvaceans ([Fig. 1][1]A). Chordates include vertebrates, cephalochordates, and urochordates, and urochordates are divided into ascidians, thaliaceans, and larvaceans. Larvaceans may be derived from the most basal branch of

Published
2001
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27. 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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28. 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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29. 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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30. 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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31. 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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32. FERTILIZATION IN OIKOPLEURA-DIOICA (TUNICATA, APPENDICULARIA) - ACROSOME REACTION, CORTICAL REACTION AND SPERM-EGG FUSION

Author

Gabriel Gorsky, Robert Fenaux, Linda Z. Holland, Station Zoologique de Villefranche, and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 0303 health sciences, Acrosome reaction, Cortical granule, Vitelline membrane, Acrosomal membrane, Anatomy, Biology, 010603 evolutionary biology, 01 natural sciences, Sperm, Cell biology, 03 medical and health sciences, medicine.anatomical_structure, Sperm entry, embryonic structures, medicine, Cortical reaction, Animal Science and Zoology, Acrosome, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, Developmental Biology
Abstract

Fine structural changes in the egg and sperm are described during gamete interaction in Oikopleura dioica, an appendicularian tunicate. The unfertilized egg has a vitelline layer 80 nm thick and a perivitelline space about 5 μm wide. In the peripheral cytoplasm are a few cortical granules 0.6×0.7 μm in diameter and areas rich in parallel cisternae of rough endoplasmic reticulum alternating with areas rich in long mitochondria. In the deeper cytoplasm the predominant organelles are multivesicular bodies. From 25 s to 60 s after insemination, the egg transiently elongates, although with no obvious cytoplasmic rearrangement, and the egg surface becomes bumpy. During this interval sperm enter the egg, and the cortical granules undergo exocytosis. After expulsion into the perivitelline space, the cortical granule contents do not appear to change their shape or blend with the vitelline layer, which neither elevates further nor loses its ability to bind sperm. On encountering the egg, the sperm undergoes an acrosome reaction involving exocytosis of the acrosome and production of an acrosomal tubule. The acrosomal contents bind the sperm to the vitelline layer, and the posterior portion of the acrosomal membrane and the anterior portion of the nuclear envelope evaginate together to form an acrosomal tubule, which fuses with the egg plasma membrane to form a fertilization cone. By 45 s after insemination, the sperm nucleus, centriole, mitochondrion and at least the anterior portion of the axoneme are within the fertilization cone. By 60 s sperm entry is complete. In having eggs with a cortical reaction and sperm with an acrosome reaction, O. dioica resembles echinoderms and enteropneusts and differs markedly from ascidian tunicates, which lack both these features. The relatively unmodified pattern of gamete interaction in O. dioica in comparison with the highly modified pattern in ascidians is difficult to reconcile with the neoteny theory that appendicularians have evolved via ascidian ancestors. The present results are more consistent with the idea that an appendicularian-like ancestor gave rise to ascidians.

Published
1988
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