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Zhou, M.; Zhu, Y.; D'Ovidio, F.; Park, Y.-h.; Durand, I.; Kestenare, E.; Sanial, V.; Van-beek, P.; Queguiner, B.; Carlotti, F.; Blain, S.. |
Mean currents, horizontal diffusivity and upwelling on the Kerguelen Plateau and the deep basin east of the Kerguelen Islands were studied using 48 World Ocean Circulation Experiment (WOCE) Standard Surface Velocity Program (SVP) drifters deployed during the 2011 austral spring KEOPS II (KErguelen Ocean Plateau compared Study II) cruise. These drifter data were analyzed based on autocovariances for temporal scales, least-squares fitted streamfunctions for estimating mesoscale mean currents, wind stress fields and Ekman pumping, and Taylor's single particle diffusivity for estimating horizontal dispersion of surface waters. The results have revealed the shelfbreak current on the southern and eastern shelf slopes of the Kerguelen Islands, transport of... |
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Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00295/40621/39568.pdf |
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Cavagna, A. J.; Fripiat, F.; Elskens, M.; Mangion, P.; Chirurgien, L.; Closset, I.; Lasbleiz, M.; Florez-leiva, L.; Cardinal, D.; Leblanc, K.; Fernandez, C.; Lefevre, D.; Oriol, L.; Blain, S.; Queguiner, B.; Dehairs, F.. |
Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO3− and NH4+), and nitrification rates were measured at eight stations in austral spring 2011 (October–November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1 respectively)... |
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Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40561/39448.pdf |
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Lasbleiz, M.; Leblanc, K.; Blain, S.; Ras, J.; Cornet-barthaux, V.; Nunige, S. Helias; Queguiner, B.. |
The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October-November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m(-2) for chlorophyll a 314 to 744 mmol m(-2) for biogenic silica (BSi), 1106 to 2268 mmol m(-2) for particulate organic carbon, 215 to 436 mmol m(-2) for particulate organic nitrogen, and 29.3 to 39.0 mmol m(-2) for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost... |
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Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40222/39345.pdf |
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Crombet, Y.; Leblanc, K.; Queguiner, B.; Moutin, T.; Rimmelin, P.; Ras, J.; Claustre, H.; Leblond, N.; Oriol, L.; Pujo-pay, M.. |
The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco), and total chlorophyll-a (TChl-a) were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM) encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM), fucoxanthin (DFM) and TChl-a (DCM) were evidenced during both seasons with maximal... |
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Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24393/22421.pdf |
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Mantoura, F; Coppola, Laurent; Cousin, M.; Antoine, David; Beguery, Laurent; Blain, Stephane; Bouin, Marie-noelle; Cadiou, Jean-francois; Durrieu De Madron, Xavier; Forget, Philippe; Fraunie, Philippe; Gojak, Carl; Gorsky, Gaby; Goyet, Catherine; Lebaron, Philippe; Lellouche, Jean-michel; Ludwig, Hubert; Molcard, Anne; Mortier, Laurent; Petit De La Villeon, Loic; Petrenko, Anne; Piazzola, J.; Queguiner, B.; Raimbault, Patrick; Rigaud, Vincent; Sempere, Richard; Tamburini, Jean-simon; Testor, Pierre; Vuillemin, Renaud; Zakardjian, B.. |
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Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00122/23341/21166.pdf |
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Leblanc, K.; Aristegui, J.; Armand, L.; Assmy, P.; Beker, B.; Bode, A.; Breton, E.; Cornet, V.; Gibson, J.; Gosselin, M. -p.; Kopczynska, E.; Marshall, H.; Peloquin, J.; Piontkovski, S.; Poulton, A. J.; Queguiner, B.; Schiebel, R.; Shipe, R.; Stefels, J.; Van Leeuwe, M. A.; Varela, M.; Widdicombe, C.; Yallop, M.. |
Phytoplankton identification and abundance data are now commonly feeding plankton distribution databases worldwide. This study is a first attempt to compile the largest possible body of data available from different databases as well as from individual published or unpublished datasets regarding diatom distribution in the world ocean. The data obtained originate from time series studies as well as spatial studies. This effort is supported by the Marine Ecosystem Model Inter-Comparison Project (MAREMIP), which aims at building consistent datasets for the main plankton functional types (PFTs) in order to help validate biogeochemical ocean models by using carbon (C) biomass derived from abundance data. In this study we collected over 293 000 individual... |
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Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00373/48464/48718.pdf |
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Closset, I.; Lasbleiz, M.; Leblanc, K.; Queguiner, B.; Cavagna, A. -j.; Elskens, M.; Navez, J.; Cardinal, D.. |
A massive diatom bloom is observed each year in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). We measured biogenic silica production and dissolution fluxes (rho Si and rho Diss, respectively) in the mixed layer in the vicinity of the Kerguelen Plateau during austral spring 2011 (KEOPS-2 cruise). We compare results from a high-nutrient low-chlorophyll reference station and stations with different degrees of iron enrichment and bloom conditions. Above the plateau biogenic rho Si are among the highest reported so far in the Southern Ocean (up to 47.9 mmol m(-2) d(-1)). Although significant (10.2 mmol m(-2) d(-1) on average), rho Diss were generally much lower than production rates. Uptake ratios (rho Si : rho C and rho... |
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Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40220/39341.pdf |
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Rembauville, M.; Blain, S.; Armand, L.; Queguiner, B.; Salter, I.. |
The biological composition of the material exported to a moored sediment trap located under the winter mixed layer of the naturally fertilized Kerguelen Plateau in the Southern Ocean was studied over an annual cycle. Despite iron availability in spring, the annual particulate organic carbon (POC) export (98.2 mmol m(-2)) at 289m was low, but annual biogenic silica export was significant (114 mmol m(-2)). This feature was related to the abundance of empty diatom cells and the ratio of full to empty cells exerted a first-order control in BSi : POC export stoichiometry of the biological pump. Chaetoceros Hyalochaete spp. and Thalassiosira antarctica resting spores were responsible for more than 60% of the annual POC flux that occurred during two very short... |
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Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40579/39498.pdf |
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