Particle flux in the northeast Atlantic Ocean during the POMME experiment (2001) : Results from mass, carbon, nitrogen, and lipid biomarkers from the drifting sediment traps.

During 48 hour stations during the three Programme Océan Multidisciplinaire Méso Echelle (POMME) cruises in 2001 (late winter, spring, and late summer) at different locations within the region studied (38°-45°N, 15°-21°W), drifting sediment traps were deployed at 200 m and 400 m. Fluxes increased from late winter (POMME 1) to spring (POMME 2), with highest values in the North Atlantic gyre (109.1, 20.1, and 3.5 mg m À2 d À1 for mass, C, and N, respectively) and decreased during POMME 3 to reach threshold values (19.1 ± 6.0, 4.4 ± 1.1, and 0.7 ± 0.2 mg m À2 d À1 , respectively). Lipid class tracers and their fatty acid composition analyzed by gaseous chromatography were used to assess the quality and quantity of organic matter fluxes. Wide seasonal variability was observed in biogenic lipid fluxes (0.42 ± 0.19 and 0.39 ± 0.13 mg m À2 d À1 , 1.78 ± 1.08 and 0.69 ± 0.56 mg m À2 d À1 , and 0.71 ± 0.14 and 0.45 mg m À2 d À1 on average at 200 m and 400 m during late winter, spring, and late summer, respectively) in relation with the development of the spring phytoplankton bloom. In a northern persistent anticyclonic eddy a major export of algal matter occurred through zooplankton activity. In contrast with this pattern, the southernmost anticyclonic eddy exhibited the lowest particle fluxes in relation to the low productivity and the high bacterial carbon demand prevailing in the surface waters. In the main cyclonic structure (C4) and the saddle zone (during POMME 2) the pattern of lipid biotracers reflected the permanence of a zooplankton community and likely advective transfer of matter between 43.5°N and 42°N through subsurface water circulation