Organic carbon and opal in deep sea sediments of the southern and eastern Weddell Sea

• Main Author: Schlüter, Michael
• Format: Dataset
• Language: English
• Published: PANGAEA 1990
• Subjects: ANT-V/4; ANT-VI/3; Atka Bay; AWI_Paleo; Barents Sea; Camp Norway; Eastern Weddell Sea; Southern Ocean; Filchner Trough; Giant box corer; GKG; Halley Bay; Kapp Norvegia; Lyddan Island; Maud Rise; MG; ms_opal; MUC; Multiboxcorer; MultiCorer; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Polarstern; PS10; PS10/672; PS10/673; PS10/675; PS10/678; PS10/684; PS10/686; PS10/690; PS10/699; PS10/701; PS10/703; PS10/707; PS10/711; PS10/719; PS10/725; PS10/738; PS10/748; PS10/757; PS10/766; PS10/778; PS10/782; PS10/784; PS10/804; PS10/818; PS10/820; PS10/824; PS12; PS12/289; Atka; Norway; Weddell; Weddell Sea; Berichte zur Polarforschung; Polar Research; Polarforschung; Reports on polar research
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.712512; https://doi.org/10.1594/PANGAEA.712512

During the ANT V14 (1986187) and ANT V113 (1987188) cruises of R.V. Polarstern sedirnents from the eastern, southern and central Weddell Sea were sarnpled with a boxcorer andlor a multicorer. The 24 sampling locations are distributed over the whole depth range, from shelf to pelagic environments. Porewater concentrations of aluminium, fluoride, manganese, nitrate, nitrite, oxygen and silicate, the pH and the alkalinity were measured. Of the sediment the opal, calcium carbonate and organic carbon content were quantified. The 210Pb-profile was measured for three sedirnent cores. This investigation deals with the estimation of the amounts of opal and organic carbon (Corg) that are transported into the sediment, the regional distribution of these flux rates and the early diagenetic processes that control the preservation of organic carbon and opal in the sediment. The flux and degradation rates of organic carbon were determined by modelling the rneasured oxygen and nitrate profiles. The highest flux and degradation rates were found in the eastern shelf sediments. Due to the high Corg-flux (>500 mmol C m**-2 a-1) in this area the oxic environment is restricted to the upper 3 cm of the sediment. In contrast to this, the oxic Zone in the pelagic sedirnents of the Weddell Sea has probably an extension of a few meters. The Corg-flux here, computed from the flux of nitrate throug h the sedimentlwater-interface, is less than 50 mmol C m**-2 a**-1. The flux of organic carbon into the sediments of the continental slope area is usually intermediate between the values computed for the shelf and pelagic sediments. Exceptions are the continental slope region north of Halley Bay. In these sediments the measured oxygen and nitrate profiles indicate a relatively high organic carbon flux. This could be a result of the recurrent development of a coastal polynia in this area. The bioturbation rate determined in this region by a 210Pb-profile is 0,019 cm**2 a**-1. In the Weddell Sea the opal content at the sediment surface (0-1 cm ...