High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from ^234Th fluxes ...

• Main Authors: Lemaitre, Nolwenn, Planchon, Frédéric, Planquette, Hélène, Dehairs, Frank, Fonseca-Batista, Debany, Roukaerts, Arnout, Deman, Florian, Tang, Yi, Mariez, Clarisse, Sarthou, Géraldine
• Format: Text
• Language: English
• Published: ETH Zurich 2018
• Subjects: Irminger Basin; North Atlantic
• Online Access: https://dx.doi.org/10.3929/ethz-b-000303474; http://hdl.handle.net/20.500.11850/303474

In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 (^234Th) with the ratio of POC to ^234Th of sinking particles at the depth of export. Particles were collected in two size classes ( > 53 and 1–53µm) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4mmolm−2d−1 in the Irminger basin, where the bloom was close to its maximum, to 12mmolm−2d−1 near the Iberian Margin, where the bloom had already declined. In addition to the state of progress of the bloom, variations of the POC export fluxes were also related to the phytoplankton size and community structure. In line with previous studies, the presence of coccolithophorids and diatoms ... : Biogeosciences, 15 (21) ...