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| Registros recuperados: 14 | |
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| Caputi, Luigi; Carradec, Quentin; Eveillard, Damien; Kirilovsky, Amos; Pelletier, Eric; Karlusich, Juan J. Pierella; Vieira, Fabio Rocha Jimenez; Villar, Emilie; Chaffron, Samuel; Malviya, Shruti; Scalco, Eleonora; Acinas, Silvia G.; Alberti, Adriana; Aury, Jean-marc; Benoiston, Anne-sophie; Bertrand, Arnaud; Biard, Tristan; Bittner, Lucie; Boccara, Martine; Brum, Jennifer R.; Brunet, Cedric; Busseni, Greta; Carratala, Anna; Claustre, Herve; Coelho, Luis Pedro; Colin, Sbastien; D'Aniello, Salvatore; Da Silva, Corinne; Del Core, Marianna; Dore, Hugo; Gasparini, Stephane; Kokoszka, Florian; Jamet, Jean-louis; Lejeusne, Christophe; Lepoivre, Cyrille; Lescot, Magali; Lima-mendez, Gipsi; Lombard, Fabien; Lukes, Julius; Maillet, Nicolas; Madoui, Mohammed-amin; Martinez, Elodie; Mazzocchi, Maria Grazia; Neou, Mario B.; Paz-yepes, Javier; Poulain, Julie; Ramondenc, Simon; Romagnan, Jean-baptiste; Roux, Simon; Manta, Daniela Salvagio; Sanges, Remo; Speich, Sabrina; Sprovieri, Mario; Sunagawa, Shinichi; Taillandier, Vincent; Tanaka, Atsuko; Tirichine, Leila; Trottier, Camille; Uitz, Julia; Veluchamy, Alaguraj; Vesela, Jana; Vincent, Flora; Yau, Sheree; Kandels-lewis, Stefanie; Searson, Sarah; Dimier, Cline; Picheral, Marc; Bork, Peer; Boss, Emmanuel; De Vargas, Colomban; Follows, Michael J.; Grimsley, Nigel; Guidi, Lionel; Hingamp, Pascal; Karsenti, Eric; Sordino, Paolo; Stemmann, Lars; Sullivan, Matthew B.; Tagliabue, Alessandro; Zingone, Adriana; Garczarek, Laurence; D'Ortenzio, Fabrizio; Testor, Pierre; Not, Fabrice; D'Alcala, Maurizio Ribera; Wincker, Patrick; Bowler, Chris; Iudicone, Daniele; Gorsky, Gabriel; Jaillon, Olivier; Karp-boss, Lee; Krzic, Uros; Ogata, Hiroyuki; Pesant, Stephane; Raes, Jeroen; Reynaud, Emmanuel G.; Sardet, Christian; Sieracki, Mike; Velayoudon, Didier; Weissenbach, Jean. |
| Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities we explored the comprehensive bio‐oceanographic and ‐omics datasets from Tara Oceans in the context of the iron products from two state‐of‐the‐art global scale biogeochemical models. We obtained novel information about adaptation and acclimation towards iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole sub‐communities co‐varying with... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00475/58680/61184.pdf |
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| Sauzède, Raphaëlle; Martinez, Elodie; Maes, Christophe; De Fommervault, Orens Pasqueron; Poteau, Antoine; Mignot, Alexandre; Claustre, Hervé; Uitz, Julia; Oziel, Laurent; Maamaatuaiahutapu, Keitapu; Rodier, Martine; Schmechtig, Catherine; Laurent, Victoire. |
| The South Pacific Subtropical Gyre (SPSG) is a vast and remote oceanic system where the variability in phytoplankton biomass and production is still largely uncertain due to the lack of in situ biogeochemical observations. The SPSG is an oligotrophic environment where the ecosystem is controlled predominantly by nutrient depletion in surface waters. However, this dynamic is altered in the vicinity of islands where increased biological activity occurs (i.e. the island mass effect, IME). This study mainly focuses on in situ observations which show evidence of an IME leeward of Tahiti (17.7°S - 149.5°W), French Polynesia. Physical and biogeochemical observations collected with two Biogeochemical-Argo profiling floats are used to investigate the dynamics of... |
| Tipo: Text |
Palavras-chave: Phytoplankton biomass; Biogeochemical-Argo floats; Island mass effect; South Pacific Subtropical Gyre. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71130/69445.pdf |
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| Le Moullac, Gilles; Tiapari, Jerome; Teissier, Hinano; Martinez, Elodie; Cochard, Jean-claude. |
| The growth and reproductive cycle of cultured black-lipped pearl oysters, Pinctada margaritifera (L.), were studied in the Gambier Islands (134°52' W, 23°07' S) from September 2002 to August 2003. Temperatures were recorded throughout the year, revealing seasonal temperature variations between 22.3 °C and 27.8 °C. The mean annual chlorophyll a value, as computed from satellite data, was 0.188 ± 0.075 µg L-1. To study growth and reproduction, 720 two-year-old individuals were ear hung on longlines suspended at a depth of 7 m. Samples were taken twice a month to obtain the following measurements: shell height; wet weight of flesh and total oyster; dry weight of adductor muscle, mantle and visceral mass; and glycogen content. Gonad development was also... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Pinctada margaritifera; Growth; Reproduction; Temperature; Chlorophyll; Seasonality; Gambier archipelago. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00040/15099/13570.pdf |
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| Martinez, Elodie; Raapoto, Hirohiti; Maes, Christophe; Maamaatuaihutapu, Keitapu. |
| The Marquesas form an isolated group of small islands in the Central South Pacific where quasi-permanent biological activity is observed. During La Niña events, this biological activity, shown by a net increase of chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass), is particularly strong. It has been hypothesized that this strong activity is due to iron-rich waters advected from the equatorial region to the Marquesas by tropical instability waves (TIWs). Here we investigate this hypothesis over 18 years by combining satellite observations, re-analyses of ocean data, and Lagrangian diagnostics. Four La Niña events ranging from moderate to strong intensity occurred during this period, and our results show that the Chl plume within the... |
| Tipo: Text |
Palavras-chave: Tropical instability waves; La Nina; Chlorophyll-a concentration variability; Ocean colour; Island mass effect; Marquesas islands; Oceanography; Satellite observations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00437/54858/56346.pdf |
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| Dobler, Delphine; Huck, Thierry; Maes, Christophe; Grima, Nicolas; Blanke, Bruno; Martinez, Elodie; Ardhuin, Fabrice. |
| In the open ocean, floating surface debris such as plastics concentrate in five main accumulation zones centered around 30° latitude, far from highly turbulent areas. Using Lagrangian advection of numerical particles by surface currents from ocean model reanalysis, previous studies have shown long-distance connection from the accumulation zones of the South Indian to the South Pacific oceans. An important physical process affecting surface particles but missing in such analyses is wave-induced Stokes drift. Taking into account surface Stokes drift from a wave model reanalysis radically changes the fate of South Indian particles. The convergence region moves from the east to the west of the basin, so particles leak to the South Atlantic rather than the... |
| Tipo: Text |
Palavras-chave: Marine debris; Microplastics; Stokes drift; Indian Ocean; Lagrangian analysis; Ocean surface pathways. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00512/62320/69273.pdf |
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| Cassianides, Angelina; Martinez, Elodie; Maes, Christophe; Carton, Xavier; Gorgues, Thomas. |
| The Marquesas islands are a place of strong phytoplanktonic enhancement, whose original mechanisms have not been explained yet. Several mechanisms such as current−bathymetry interactions or island run-off can fertilize waters in the immediate vicinity or downstream of the islands, allowing phytoplankton enhancement. Here, we took the opportunity of an oceanographic cruise carried out at the end of 2018, to combine in situ and satellite observations to investigate two phytoplanktonic blooms occurring north and south of the archipelago. First, Lagrangian diagnostics show that both chlorophyll-a concentrations (Chl) plumes are advected from the islands. Second, the use of Finite-size Lyaponov Exponent and frontogenesis diagnostics reveal how the Chl plumes... |
| Tipo: Text |
Palavras-chave: Mesoscale dynamics; Chlorophyll-a concentration variability; Coastal fertilization; Horizontal advection; Marquesas islands. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00649/76115/77077.pdf |
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| Martinez, Elodie; Brini, Anouar; Gorgues, Thomas; Drumetz, Lucas; Roussillon, Joana; Tandeo, Pierre; Maze, Guillaume; Fablet, Ronan. |
| Phytoplankton plays a key role in the carbon cycle and supports the oceanic food web. While its seasonal and interannual cycles are rather well characterized owing to the modern satellite ocean color era, its longer time variability remains largely unknown due to the short time-period covered by observations on a global scale. With the aim of reconstructing this longer-term phytoplankton variability, a support vector regression (SVR) approach was recently considered to derive surface Chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) from physical oceanic model outputs and atmospheric reanalysis. However, those early efforts relied on one particular algorithm, putting aside the question of whether different algorithms may have specific... |
| Tipo: Text |
Palavras-chave: Phytoplankton time-series reconstruction; Ocean color; Neural networks; Support vector regression; Multi-layer perceptron; Physical predictors. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00667/77871/80017.pdf |
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| Maes, Christophe; Blanke, Bruno; Martinez, Elodie. |
| This study investigates the structure and intensity of the surface pathways connecting to and from the central areas of the large-scale convergence regions of the eastern Pacific Ocean. Surface waters are traced with numerical Lagrangian particles transported in the velocity field of three different ocean models with horizontal resolutions that range from ¼° to 1/32°. The connections resulting from the large-scale convergent Ekman dynamics agree qualitatively but are strongly modulated by eddy variability that introduces meridional asymmetry in the amplitude of transport. Lagrangian forward-in-time integrations are used to analyze the fate of particles originating from the central regions of the convergence zones and highlight specific outflows not yet... |
| Tipo: Text |
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| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00324/43496/43013.pdf |
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| Martinez, Elodie; Antoine, David; D'Ortenzio, Fabrizio; De Boyer Montegut, Clément. |
| Phytoplankton chlorophyll-a (Chl) seasonal cycles of the North Atlantic are described using satellite ocean color observations covering the 1980s and the 2000s. The study region is where warmer SST and higher Chl in the 2000s as compared to the 1980s have been reported. It covers latitudes from 30 degrees N-50 degrees N and longitudes from 60 degrees W-0 degrees W, where two phytoplankton blooms take place: a spring bloom that follows stratification of upper layers, and a fall bloom due to nutrient entrainment through deepening of the mixed layer. In the 1980s, spring and fall blooms were of similar amplitude over the entire study region. In the 2000s, the fall bloom was weaker in the eastern Atlantic (east of 40 degrees W), because of a delayed deepening... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00054/16556/14070.pdf |
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| Martinez, Elodie; Gorgues, Thomas; Lengaigne, Matthieu; Fontana, Clement; Sauzède, Raphaëlle; Menkes, Christophe; Uitz, Julia; Di Lorenzo, Emanuele; Fablet, Ronan. |
| Monitoring the spatio-temporal variations of surface chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) greatly benefited from the availability of continuous and global ocean color satellite measurements from 1997 onward. These two decades of satellite observations are however still too short to provide a comprehensive description of Chl variations at decadal to multi-decadal timescales. This paper investigates the ability of a machine learning approach (a non-linear statistical approach based on Support Vector Regression, hereafter SVR) to reconstruct global spatio-temporal Chl variations from selected surface oceanic and atmospheric physical parameters. With a limited training period (13 years), we first demonstrate that Chl variability... |
| Tipo: Text |
Palavras-chave: Machine learning; Phytoplankton variability; Satellite ocean color; Decadel variability; Global scale. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75314/75810.pdf |
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| Raapoto, Hirohiti; Martinez, Elodie; Petrenko, Anne; Doglioli, Andrea; Gorgues, Thomas; Sauzède, Raphaëlle; Maamaatuaiahutapu, Keitapu; Maes, Christophe; Menkes, Christophe; Lefèvre, Jérôme. |
| A remarkable chlorophyll‐a concentration (Chl, a proxy of phytoplankton biomass) plume can be noticed on remotely sensed ocean color observations at the boundary separating the equatorial mesotrophic from the subtropical oligotrophic waters in the central South Pacific Ocean. This prominent biological feature is known as the island mass effect of the Marquesas archipelago. Waters surrounding these islands present high macronutrient concentrations but an iron depletion. In this study, the origin of Chl enhancement is investigated using a modeling approach. Four simulations based on identical physical and biogeochemical forcings but with different iron sources are conducted and analyzed. Only simulations considering an iron input from the island sediments... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00592/70397/68481.pdf |
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| Sauzède, Raphaëlle; Martinez, Elodie; Pasqueron De Fommervault, Orens; Poteau, Antoine; Mignot, Alexandre; Maes, Christophe; Claustre, Hervé; Uitz, Julia; Maamaatuaiahutapu, Keitapu; Rodier, Martine; Schmechtig, Catherine; Laurent, Victoire. |
| The South Pacific Subtropical Gyre (SPSG) is a vast and remote area where large uncertainties on variability in phytoplankton biomass and production remain due to the lack of biogeochemical in situ observations. In such oligotrophic environments, ecosystems are predominantly controlled by nutrients depletion in surface waters. However, this oligotrophic character can be disturbed in the vicinity of islands where enhancement of biological activity is known to occur (i.e. the island mass effect, IME). This study mainly focuses on in situ observations showing that an IME can be evidenced leeward of Tahiti (17.7° S–149.5° W), French Polynesia. Concomitant physical and biogeochemical observations collected with two Biogeochemical-Argo (BGC-Argo) profiling... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00421/53295/54108.pdf |
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| Messié, M.; Petrenko, A.; Doglioli, A.m.; Aldebert, C.; Martinez, Elodie; Koenig, G.; Bonnet, S.; Moutin, T.. |
| In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in... |
| Tipo: Text |
Palavras-chave: Island mass effect; Lagrangian analysis; Nitrogen fixation; Nutrient supply; Oligotrophic ocean; Phytoplankton bloom. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00600/71162/69489.pdf |
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| Maximenko, Nikolai; Corradi, Paolo; Law, Kara Lavender; Van Sebille, Erik; Garaba, Shungudzemwoyo P.; Lampitt, Richard Stephen; Galgani, Francois; Martinez-vicente, Victor; Goddijn-murphy, Lonneke; Veiga, Joana Mira; Thompson, Richard C.; Maes, Christophe; Moller, Delwyn; Löscher, Carolin Regina; Addamo, Anna Maria; Lamson, Megan R.; Centurioni, Luca R.; Posth, Nicole R.; Lumpkin, Rick; Vinci, Matteo; Martins, Ana Maria; Pieper, Catharina Diogo; Isobe, Atsuhiko; Hanke, Georg; Edwards, Margo; Chubarenko, Irina P.; Rodriguez, Ernesto; Aliani, Stefano; Arias, Manuel; Asner, Gregory P.; Brosich, Alberto; Carlton, James T.; Chao, Yi; Cook, Anna-marie; Cundy, Andrew B.; Galloway, Tamara S.; Giorgetti, Alessandra; Goni, Gustavo Jorge; Guichoux, Yann; Haram, Linsey E.; Hardesty, Britta Denise; Holdsworth, Neil; Lebreton, Laurent; Leslie, Heather A.; Macadam-somer, Ilan; Mace, Thomas; Manuel, Mark; Marsh, Robert; Martinez, Elodie; Mayor, Daniel J.; Le Moigne, Morgan; Molina Jack, Maria Eugenia; Mowlem, Matt Charles; Obbard, Rachel W.; Pabortsava, Katsiaryna; Robberson, Bill; Rotaru, Amelia-elena; Ruiz, Gregory M.; Spedicato, Maria Teresa; Thiel, Martin; Turra, Alexander; Wilcox, Chris. |
| Plastics and other artificial materials pose new risks to the health of the ocean. Anthropogenic debris travels across large distances and is ubiquitous in the water and on shorelines, yet, observations of its sources, composition, pathways, and distributions in the ocean are very sparse and inaccurate. Total amounts of plastics and other man-made debris in the ocean and on the shore, temporal trends in these amounts under exponentially increasing production, as well as degradation processes, vertical fluxes, and time scales are largely unknown. Present ocean circulation models are not able to accurately simulate drift of debris because of its complex hydrodynamics. In this paper we discuss the structure of the future integrated marine debris observing... |
| Tipo: Text |
Palavras-chave: Plastics; Marine debris; Sensor development; Observing network; Ecosystemstressors; Maritime safety. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62272/66477.pdf |
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| Registros recuperados: 14 | |
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