Eintrag, Akkumulation und Überlieferung von organischem Kohlenstoff in Oberflächensedimenten des Europäischen Nordmeeres (engl. titel: Input, accumulation, and preservation of organic carbon in surface sediments of the European Nordic seas)
AbstractA new driven measuring and sampling device was developed, capable to performe in situ measurements of porewater oxygen and formationfactor depth distributions within the upper sediment layers. The wire driven system was designed for the use even in ice covered regions as the East Greenland S...
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| Format: | Thesis |
| Language: | unknown |
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1997
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| Online Access: | https://epic.awi.de/id/eprint/5132/ https://hdl.handle.net/10013/epic.15700 |
| Summary: | AbstractA new driven measuring and sampling device was developed, capable to performe in situ measurements of porewater oxygen and formationfactor depth distributions within the upper sediment layers. The wire driven system was designed for the use even in ice covered regions as the East Greenland Sea and successfully employed at nine stations. Out of sediment cores taken by the implemented corer unit from the immediate vicinity of the measurement location other geochemical parameters were determined in laboratory.The production of oxygen microsensors for in situ and shipboard use was established at GEOMAR. In order to calculate the diffusive oxygen flux through the water/sediment interface the oxygen depth profiles measured with microsensors were fit by an exponential function. Out of that the Corg-flux onto the sediment surface was calculated, assuming oxic respiration in these well oxygenated sediments to be the main process of carbon degradation. Compared with fluxes obtained out of in situ oxygen measurements laboratory measured profiles lead to an overestimation of diffusive fluxes through the water/sediment-surface, dependending on waterdepth whereas oxygen penetration depth is much less affected.The Corg-flux onto the sediment surface was found to be relatively low in the region offshore East Greenland. Typical values reach from 3 to 8 gCm-2a-1 on the shelf and from 0.5 to 1 gCm-2a-1 at the deeper locations of the Greenland and Norwegian Sea respectively. Fluxes are found to be higher in summer than in fall by a factor of about 1.4. For some stations organic carbon akkumulation rates were calculated, considering published sedimentation rates of the respect location. In shelf sediments 0.2 to 0.3 gm-2a-1 of organic carbon akkumulates whereas in deep-sea sediments of the Nordic Seas akkumulation rates lie between 0.02 and 0.08 gCm-2a-1. In relation to the influx onto the sediment surface less than 5% of organic carbon are buried within surface sediments on the shelf an 7 to 21% at deep locations ... |
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