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| Gazeau, Frédéric; Van Wambeke, France; Maranon, Emilio; Perez-lorenzo, Maria; Alliouane, Samir; Stolpe, Christian; Blasco, Thierry; Leblond, Nathalie; Zancker, Birthe; Engel, Anja; Marie, Barbara; Dinasquet, Julie; Guieu, Cécile. |
| Although atmospheric dust fluxes from arid as well as human-impacted areas represent a significant source of nutrients to surface waters of the Mediterranean Sea, studies focusing on the evolution of the metabolic balance of the plankton community following a dust deposition event are scarce and none were conducted in the context of projected future levels of temperature and pH. Moreover, most of the experiments took place in coastal areas. In the framework of the PEACETIME project, three dust-addition perturbation experiments were conducted in 300-L tanks filled with surface seawater collected in the Tyrrhenian Sea (TYR), Ionian Sea (ION) and in the Algerian basin (FAST) onboard the R/V “Pourquoi Pas?” in late spring 2017. For each experiment, six tanks... |
| Tipo: Text |
Palavras-chave: Mediterranean Sea; Atmospheric deposition; Plankton community metabolism; Carbon export; Ocean acidification; Ocean warming. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/79967/82900.pdf |
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| Bretagnon, Marine; Paulmier, Aurelien; Garcon, Veronique; Dewitte, Boris; Illig, Serena; Leblond, Nathalie; Coppola, Laurent; Campos, Fernando; Velazco, Federico; Panagiotopoulos, Christos; Oschlies, Andreas; Martin Hernandez-ayon, J.; Maske, Helmut; Vergara, Oscar; Montes, Ivonne; Martinez, Philippe; Carrasco, Edgardo; Grelet, Jacques; Desprez-de-gesincourt, Olivier; Maes, Christophe; Scouarnec, Lionel. |
| The fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O-2 conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. Data provided high-temporal-resolution O-2 series characterising two seasonal steady states at the... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00486/59764/62889.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... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00448/56006/57514.pdf |
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| Heimbuerger, Lars-eric; Migon, Christophe; Losno, Rémi; Miquel, Juan-carlos; Thibodeau, Benoit; Stabholz, Marion; Dufour, Aurelie; Leblond, Nathalie. |
| We examined metal (Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb) and particulate organic carbon (OC) concentrations of the marine vertical export flux at the DYFAMED time-series station in the Northwestern Mediterranean Sea. We present here the first data set of natural and anthropogenic metals from sediment trap moorings deployed at 1000 m-depth between 2003 and 2007 at the DYFAMED site. A highly significant correlation was observed between most metal concentrations, whatever the nature and emission source of the metal. Cu, Zn and Cd exhibit different behaviors, presumably due to their very high solubility and complexation with organic ligands. The observed difference of atmospheric and marine fluxes in terms of temporal variability and elemental... |
| Tipo: Text |
Palavras-chave: Trace metals; Sediment trap; Mediterranean Sea; Vertical export flux; Ballasting. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00176/28774/27247.pdf |
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| Knapp, Angela N.; Mccabe, Kelly M.; Grosso, Olivier; Leblond, Nathalie; Moutin, Thierry; Bonnet, Sophie. |
| Constraining the rates and spatial distribution of di-nitrogen (N2) fixation fluxes to the ocean informs our understanding of the environmental sensitivities of N2 fixation as well as the timescale over which the fluxes of nitrogen (N) to and from the ocean may respond to each other. Here we quantify rates of N2 fixation as well as its contribution to export production along a zonal transect in the Western Tropical South Pacific (WTSP) Ocean using N isotope (δ15N) budgets. Comparing measurements of water column nitrate + nitrite δ15N with the δ15N of sinking particulate N at a western, central, and eastern station, these δ15N budgets indicate high, modest, and low rates of N2 fixation at the respective stations. The results also imply that N2 fixation... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00420/53117/54069.pdf |
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| Spungin, Dina; Belkin, Natalia; Foster, Rachel; Stenegren, Marcus; Caputo, Andrea; Pujo-pay, Mireille; Leblond, Nathalie; Dupouy, Cecile; Bonnet, Sophie; Berman-frank, Ilana. |
| The fate of diazotroph (N2 fixers) derived carbon (C) and nitrogen (N) and their contribution to vertical export of C and N in the Western Tropical South Pacific Ocean was studied in OUTPACE (Oligotrophy to UlTra-oligotrophy PACific Experiment). Our specific objective during OUTPACE was to determine whether autocatalytic programmed cell death (PCD) is an important mechanism affecting diazotroph mortality and a factor regulating the vertical flux of organic matter and thus the fate of the blooms. We sampled at three long duration (LD) stations of 5 days each (LDA, LDB, and LDC) where drifting sediment traps were deployed at 150, 325 and 500 m depths. LDA and LDB were characterized by high chlorophyll a (Chl a) concentrations (0.2–0.6 µg L−1) and dominated... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00419/53048/53985.pdf |
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| Caffin, Mathieu; Moutin, Thierry; Foster, Rachel Ann; Bouruet-aubertot, Pascale; Doglioli, Andrea Michelangelo; Berthelot, Hugo; Guieu, Cecile; Grosso, Olivier; Helias-nunige, Sandra; Leblond, Nathalie; Gimenez, Audrey; Petrenko, Anne Alexandra; De Verneil, Alain; Bonnet, Sophie. |
| We performed nitrogen (N) budgets in the photic layer of three contrasting stations representing different trophic conditions in the western tropical South Pacific (WTSP) Ocean during austral summer conditions (February–March 2015). Using a Lagrangian strategy, we sampled the same water mass for the entire duration of each long-duration (5 days) station, allowing us to consider only vertical exchanges for the budgets. We quantified all major vertical N fluxes both entering (N2 fixation, nitrate turbulent diffusion, atmospheric deposition) and leaving the photic layer (particulate N export). The three stations were characterized by a strong nitracline and contrasted deep chlorophyll maximum depths, which were lower in the oligotrophic Melanesian archipelago... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55074/56503.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... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00420/53113/54067.pdf |
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| Roy-barman, Matthieu; Foliot, Lorna; Douville, Eric; Leblond, Nathalie; Gazeau, Frédéric; Bressac, Matthieu; Wagener, Thibaut; Ridame, Céline; Desboeufs, Karine; Guieu, Cécile. |
| The release of lithogenic elements (which are often assumed to be insoluble) such as Aluminum (Al), Iron (Fe), Rare Earth Elements (REE), Thorium (Th) and Protactinium (Pa) by Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 days under controlled conditions including control without dust addition and dust seeding under present and future climate conditions (+3 °C and −0.3 pH unit). Unfiltered surface seawater from 3 oligotrophic regions (Tyrrhenian Sea, Ionian Sea and Algerian Basin) were used. The maximum dissolution fractions were low for all seeding experiments: less than 0.3 % for Fe, 1 % for 232Th and Al, about 2–5 % for REE and less than 6 % for Pa. Different behaviors were observed: dissolved Al increased... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00642/75456/76274.pdf |
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