Spatial budget of organic carbon flux to the seafloor of the northern North Atlantic (60 degrees N-80 degrees N)

The transfer of organic carbon from surface waters to the seafloor was calculated for the northern North Atlantic east of Greenland. This calculation is based on an empirically derived relationship between the rain rate of remineralizable organic carbon, derived by in situ O-2 profiles, water depth, and primary production. The reliability of this attempt is supported by the good correspondence of calculated rain rates with an independent data set of particle trap studies and shipboard measurements of O-2 profiles. For water depths of > 500 m the total seafloor remineralization rate is 2.7 x 10(6) tC yr(-1) for the northern North Atlantic. Low and nearly similar average rain rates of 0.60 and 0.65 gC m(-2) yr(-1) have been derived for the deep basins of the Norwegian and Greenland Seas. Therefore, 1.7-1.8% of the primary production is transferred to the seafloor of the basins. A considerably higher average flux of 3.8 gC m(-2) yr(-1) was calculated for the Iceland Plateau, where similar to 3.3% of primary produced organic carbon reaches the seafloor. The sediments of the Iceland Plateau receive 1.0 x 10(6) tC yr(-1) or similar to 37% of the organic carbon rain rate to the seafloor derived for the entire northern North Atlantic. The transfer of primary produced organic carbon below water depths of 500 and 1000 m suggests that 10.3 x 10(6) tC yr(-1) and 4.5 x 10(6) tC yr(-1) are exported from surface waters. This is 2-4.4 % of the organic carbon produced in the photic zone of the northern North Atlantic east of Greenland.