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| Trull, Thomas; Davies, Diana M.; Dehairs, Frank; Cavagna, Anne-julie; Lasbleiz, Marine; Laurenceau Cornec, Emmanuel C.; D'Ovidio, Francesco; Planchon, Frederic; Leblanc, Karine; Queguiner, Bernard; Blain, Stephane. |
| We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. The community structure was estimated from chemical and isotopic measurements (particulate organic carbon - POC; C-13-POC; particulate nitrogen -PN; N-15-PN; and biogenic silica - BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 mu m fractions). Higher values of C-13-POC (vs. co-located C-13 values for dissolved inorganic carbon -DIC) were taken as indicative of faster growth rates and higher values of N-15-PN (vs. co-located N-15-NO3 source values) as indicative of greater nitrate use (rather than ammonium use,... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00255/36642/35222.pdf |
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| Lasbleiz, Marine; Leblanc, Karine; Armand, Leanne K.; Christaki, Urania; Georges, Clement; Obernosterer, Ingrid; Queguiner, Bernard. |
| In the naturally iron-fertilized surface waters of the northern Kerguelen Plateau region, the early spring diatom community composition and contribution to plankton carbon biomass were investigated and compared with the High Nutrient Low Chlorophyll (HNLC) surrounding waters. The large iron-induced blooms were dominated by small diatom species belonging to the genera Chaetoceros (Hyalochaete) and Thalassiosira, which rapidly responded to the onset of favorable light-conditions in the meander of the Polar Front. In comparison, the iron-limited HNLC area was typically characterized by autotrophic nanoeukaryote-dominated communities and by larger and more heavily silicified diatom species (e.g. Fragilariopsis spp.). Our results support the hypothesis that... |
| Tipo: Text |
Palavras-chave: Diatoms; Carbon biomass; Plankton community structure; Natural iron fertilization; Southern Ocean. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00347/45850/45512.pdf |
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| Massicotte, Philippe; Amiraux, Rémi; Amyot, Marie-pier; Archambault, Philippe; Ardyna, Mathieu; Arnaud, Laurent; Artigue, Lise; Aubry, Cyril; Ayotte, Pierre; Bécu, Guislain; Bélanger, Simon; Benner, Ronald; Bittig, Henry C; Bricaud, Annick; Brossier, Eric; Bruyant, Flavienne; Chauvaud, Laurent; Christiansen-stowe, Debra; Claustre, Hervé; Cornet-barthaux, Véronique; Coupel, Pierre; Cox, Christine; Delaforge, Aurélie; Dezutter, Thibault; Dimier, Céline; Dominé, Florent; Dufour, Francis; Dufresne, Christiane; Dumont, Dany; Ehn, Jens; Else, Brent; Ferland, Joannie; Forget, Marie-hélène; Fortier, Louis; Gali, Marti; Galindo, Virginie; Gallinari, Morgane; Garcia, Nicole; Gerikas-ribeiro, Catherine; Gourdal, Margaux; Gourvil, Priscilla; Goyens, Clemence; Grondin, Pierre-luc; Guillot, Pascal; Guilmette, Caroline; Houssais, Marie-noëlle; Joux, Fabien; Lacour, Léo; Lacour, Thomas; Lafond, Augustin; Lagunas, José; Lalande, Catherine; Laliberté, Julien; Lambert-girard, Simon; Larivière, Jade; Lavaud, Johann; Lebaron, Anita; Leblanc, Karine; Le Gall, Florence; Legras, Justine; Lemire, Mélanie; Levasseur, Maurice; Leymarie, Edouard; Leynaert, Aude; Lopes Dos Santos, Adriana; Lourenço, Antonio; Mah, David; Marec, Claudie; Marie, Dominique; Martin, Nicolas; Marty, Constance; Marty, Sabine; Massé, Guillaume; Matsuoka, Atsushi; Matthes, Lisa; Moriceau, Brivaela; Muller, Pierre-emmanuel; Mundy, Christopher-john; Neukermans, Griet; Oziel, Laurent; Panagiotopoulos, Christos; Pangazi, Jean-jacques; Picard, Ghislain; Picheral, Marc; Pinczon Du Sel, France; Pogorzelec, Nicole; Probert, Ian; Queguiner, Bernard; Raimbault, Patrick; Ras, Joséphine; Rehm, Eric; Reimer, Erin; Rontani, Jean-françois; Rysgaard, Soren; Saint-béat, Blanche; Sampei, Makoto; Sansoulet, Julie; Schmidt, Sabine; Sempere, Richard; Sevigny, Caroline; Shen, Yuan; Tragin, Margot; Tremblay, Jean-eric; Vaulot, Daniel; Verin, Gauthier; Vivier, Frédéric; Vladoiu, Anda; Whitehead, Jeremy; Babin, Marcel. |
| The Green Edge initiative was developed to investigate the processes controlling the primary productivity and the fate of organic matter produced during the Arctic phytoplankton spring bloom (PSB) and to determine its role in the ecosystem. Two field campaigns were conducted in 2015 and 2016 at an ice camp located on landfast sea ice southeast of Qikiqtarjuaq Island in Baffin Bay (67.4797N, 63.7895W). During both expeditions, a large suite of physical, chemical and biological variables was measured beneath a consolidated sea ice cover from the surface to the bottom at 360 m depth to better understand the factors driving the PSB. Key variables such as temperature, salinity, radiance, irradiance, nutrient concentrations, chlorophyll-a concentration,... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00598/71000/69266.pdf |
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| Lafond, Augustin; Leblanc, Karine; Queguiner, Bernard; Moriceau, Brivaela; Leynaert, Aude; Cornet, Veronique; Legras, Justine; Ras, Josephine; Parenteau, Marie; Garcia, Nicole; Babin, Marcel; Tremblay, Jean-eric. |
| The Arctic Ocean is particularly affected by climate change, with changes in sea ice cover expected to impact phytoplankton primary production. During the Green Edge expedition, the development of the late spring-early summer diatom bloom was studied in relation with the sea ice retreat by multiple transects across the marginal ice zone. Biogenic silica concentrations and uptake rates were measured. In addition, diatom assemblage structures and their associated carbon biomass were determined, along with taxon-specific contributions to total biogenic silica production using the fluorescent dye PDMPO. Results indicate that a diatom bloom developed in open waters close to the ice edge, following the alleviation of light limitation, and extended 20-30 km... |
| Tipo: Text |
Palavras-chave: Diatoms; Spring bloom; Sea ice; Community composition; Baffin Bay; Arctic. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00615/72752/72021.pdf |
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| Fripiat, Francois; Corvaisier, Rudolph; Navez, Jacques; Elskens, Marc; Schoemann, Veronique; Leblanc, Karine; Andre, Luc; Cardinal, Damien. |
| Regional and seasonal variability of the Si dissolution: production ratios in the surface ocean have not been well assessed. Here, we propose a new method for determining these rates, using the Si-30-isotopic dilution technique with a high-resolution sector field inductively coupled plasma mass spectrometer (HR-SF-ICP-MS). Relative analytical precision of the isotopic measurement is better than 1%, similar to that obtained by thermal ionization-quadrupole mass spectrometry (TIMS). Accuracy and reproducibility of the isotopic measurements have been checked on artificial and natural solutions by intercomparison between two HR-SF-ICP-MS instruments and one TIMS. Measurements of real Si production and dissolution rates are illustrated for two contrasted... |
| Tipo: Text |
Palavras-chave: Isotopic fractionation; Southern ocean; Acid uptake; Waters; Phytoplankton; Environments; Biosilica; Recovery; Balance; Tracer. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00205/31607/30033.pdf |
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| Moutin, Thierry; Wagener, Thibaut; Caffin, Mathieu; Fumenia, Alain; Gimenez, Audrey; Baklouti, Melika; Bouruet-aubertot, Pascale; Pujo-pay, Mireille; Leblanc, Karine; Lefevre, Dominique; Nunige, Sandra Helias; Leblond, Nathalie; Grosso, Olivier; De Verneil, Alain. |
| Surface waters (0–200 m) of the western tropical South Pacific (WTSP) were sampled along a longitudinal 4000 km transect (OUTPACE cruise, 18 Feb., 3 Apr. 2015) during the stratified period between the Melanesian Archipelago (MA) and the western part of the SP gyre (WGY). Two distinct areas were considered for the MA, the western MA (WMA) and the eastern MA (EMA). The main carbon (C), nitrogen (N), phosphorus (P) pools and fluxes allow for characterization of the expected trend from oligotrophy to ultra-oligotrophy, and to build first-order budgets at the daily and seasonal scales (using climatology). Sea surface chlorophyll a reflected well the expected oligotrophic gradient with higher values obtained at WMA, lower values at WGY and intermediate values at... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00420/53113/54067.pdf |
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| Leblanc, Karine; Cornet, Véronique; Rimmelin-maury, Peggy; Grosso, Olivier; Hélias-nunige, Sandra; Brunet, Camille; Claustre, Hervé; Ras, Joséphine; Leblond, Nathalie; Quéguiner, Bernard. |
| This article presents data regarding the Si biogeochemical cycle during two oceanographic cruises conducted in the Southern Tropical Pacific (BIOSOPE and OUTPACE cruises) in 2005 and 2015. It involves the first Si stock measurements in this understudied region, encompassing various oceanic systems from New Caledonia to the Chilean upwelling between 8 and 34°S. Some of the lowest levels of biogenic silica standing stocks ever measured were found in this area, notably in the Southern Pacific Gyre, where Chlorophyll a concentrations are most depleted worldwide. Integrated biogenic silica stocks are as low as 1.08±0.95mmolm−2, and are the lowest stocks measured in the Southern Pacific. Size-fractionated biogenic silica concentrations revealed a non-negligible... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/56006/57514.pdf |
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