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 calc ulated for the northern North Atlantic east of Greenland. This calculation is based on an empirically derived relationship between the rain rate of re mineralizable organic carbon, derived by in situ O-2 profiles, water depth, and primary production. The reliability of this attempt is supported by th e good correspondence of calculated rain rates with an independent data set of particle trap studies and shipboard measurements of O-2 profiles. For w ater 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 avera ge rain rates of 0.60 and 0.65 gC m(-2) yr(-1) have been derived for the de ep basins of the Norwegian and Greenland Seas. Therefore, 1.7-1.8% of the p rimary production is transferred to the seafloor of the basins. A considera bly higher average flux of 3.8 gC m(-2) yr(-1) was calculated for the Icela nd Plateau, where similar to 3.3% of primary produced organic carbon reache s 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 d erived for the entire northern North Atlantic. The transfer of primary prod uced 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 wate rs. This is 2-4.4 % of the organic carbon produced in the photic zone of th e northern North Atlantic east of Greenland.