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| Kheireddine, Malika; Dall'Olmo, Giorgio; Ouhssain, Mustapha; Krokos, George; Claustre, Hervé; Schmechtig, Catherine; Poteau, Antoine; Zhan, Peng; Hoteit, Ibrahim; Jones, Burton H.. |
| The export and fate of organic carbon in the mesopelagic zone are still poorly understood and quantified due to lack of observations. We exploited data from a biogeochemical‐Argo float that was deployed in the Red Sea to study how a warm and hypoxic environment can affect the fate of the organic carbon in the ocean's interior. We observed that only 10% of the particulate organic carbon (POC) exported survived at depth due to remineralization processes in the upper mesopelagic zone. We also found that POC exported was rapidly degraded in a first stage and slowly in a second one, which may be dependent on the palatability of the organic matter. We observed that apparent oxygen utilization (AOU)‐based loss rates (a proxy of the remineralization of total... |
| Tipo: Text |
Palavras-chave: Carbon export; Carbon loss rates; Mesopelagic zone; Temperature; Oxygen; Tropical ecosystem. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00655/76730/77877.pdf |
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| Guieu, C; Roy-barman, M; Leblond, N; Jeandel, C; Souhaut, M; Le Cann, Bernard; Dufour, A; Bournot, C. |
| In the framework of the Programme Ocean Multidisciplinaire Meso Echelle (POMME) experiment, a 1.5 year record (February 2001-June 2002) of downward particle flux at 400 m and 1000 m was measured by sediment traps at four moorings located in the northeast Atlantic between 39 degrees-43 degrees N and 17 degrees-19 degrees W. Thorium-230 was used to estimate sediment trap efficiency, revealing values ranging from 18.5 to 55%. The lowest trapping efficiency was observed for the trap having experienced the highest currents. Significant interannual variability between 2001 and 2002 was clearly linked to the differences observed in the mixed layer depth. At some sites, particulate organic carbon (POC) export was higher (up to a factor of 1.6) during summer than... |
| Tipo: Text |
Palavras-chave: Sediment traps; Carbon export; Biogenic and lithogenic tracers; Mesoscale circulation; Thorium isotopes. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00000/10982/7422.pdf |
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| Amiraux, Rémi; Burot, Christopher; Bonin, Patricia; Massé, Guillaume; Guasco, Sophie; Babin, Marcel; Vaultier, Frédéric; Rontani, Jean-françois. |
| During sea-ice melt in the Arctic, primary production by sympagic (sea-ice) algae can be exported efficiently to the seabed if sinking rates are rapid and activities of associated heterotrophic bacteria are limited. Salinity stress due to melting ice has been suggested to account for such low bacterial activity. We further tested this hypothesis by analyzing samples of sea ice and sinking particles collected from May 18 to June 29, 2016, in western Baffin Bay as part of the Green Edge project. We applied a method not previously used in polar regions—quantitative PCR coupled to the propidium monoazide DNA-binding method—to evaluate the viability of bacteria associated with sympagic and sinking algae. We also measured cis-trans isomerase activity, known to... |
| Tipo: Text |
Palavras-chave: Bacteria; Sea ice; Sympagic algae; Ice biota; Viability; Stress factors; Salinity; Bactericidal free fatty acids; Carbon export. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00681/79329/81840.pdf |
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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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