Fluxes of Organic Carbon and Biogenic Silica Reaching the Seafloor: A Comparison of High Northern and Southern Latitudes of the Atlantic Ocean


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mschlueter [ at ] awi-bremerhaven.de

Abstract

Surface sediments from the high-latitude southern and northern Atlantic Ocean havebeen investigated with respect to the benthic cycle of particulate organic carbon (POC) and biogenicsilica (BSi). Special emphasis has been given to the magnitude of benthic fluxes, their spatialdistribution, their relation to particle-trap studies, and their ability to trace ice-related features.In both polar regions enhanced fluxes of POC to the seafloor were observed for polynyas, reflectingthe enhanced primary production of recurrent ice-free surface-water formation in theseregions. Very similar fluxes were observed for organic carbon in the Weddell Sea and the northernNorth Atlantic. Within the northern North Atlantic regional differences in POC fluxes were investigatedusing an empirically derived relationship between benthic POC flux, primary production,and water depth. The calculated spatial budget suggests that ¡« 2% of the primary production is exportedbelow 1000 m water depth and that 1.2 % reaches the seafloor. These values are quite similarto temperate regions within the world oceans.In contrast to organic carbon rain rates, striking differences were observed for the benthic biogenicsilica cycle. Compared to the Weddell Sea, within the Southern Ocean, a region of low BSifluxes, the BSi rain rate which reaches the seafloor of the northern North Atlantic is of minor importance,suggesting an almost negligible contribution of this area to the burial of BSi in sediments.The observed similarities to and deviations in geochemical cycles at high latitudes permita consideration of the processes responsible for the regional differences of BSi fluxes or the decouplingof the BSi and POC cycle in some sub-regions of the southern South Atlantic and thenorthern North Atlantic.



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Inbook
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Published
Eprint ID
4196
Cite as
Schlüter, M. , Sauter, E. , Schulz-Bull, D. , Balzer, W. and Suess, E. (2001): Fluxes of Organic Carbon and Biogenic Silica Reaching the Seafloor: A Comparison of High Northern and Southern Latitudes of the Atlantic Ocean , In The Northern North Atlantic: A Changing Environment (ed. P. Schäfer, W. Ritzrau, M. Schlüter, and J. Thiede), Springer, 240 .


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