Methane and hydrogen sulfide in porewater of sediment cores from the upwelling area off Namibia

DOI

Porewater concentrations of sulfate, methane, and other relevant constituents were determined on four sediment cores from the high productivity upwelling area off Namibia which were recovered from the continental slope at water depths of 1300 and 2000 m. At all four stations a distinct sulfate-methane transition zone was observed several meters below the seafloor in which both sulfate and methane are consumed. Nutrient porewater concentration profiles do not show gradient slope changes at the depths of the transition zones. Flux calculations carried out on the basis of the determined porewater profiles revealed that anaerobic methane oxidation accounts for 100% of deep sulfate reduction within the sulfate-methane transition zone and consumes the total net diffusive sulfate flux. A significant contribution of organic carbon oxidation to the reduction of sulfate at these depths could, therefore, be excluded. We state that porewater profiles of sulfate with constant gradients above the transition zones are indicative for anaerobic methane oxidation controlling sulfate reduction.

Supplement to: Niewöhner, Christine; Hensen, Christian; Kasten, Sabine; Zabel, Matthias; Schulz, Horst D (1998): Deep sulfate reduction completely mediated by anaerobic methane oxidation in sediments of the upwelling area off Namibia. Geochimica et Cosmochimica Acta, 62(3), 455-464

Identifier
DOI https://doi.org/10.1594/PANGAEA.730425
Related Identifier https://doi.org/10.1016/S0016-7037(98)00055-6
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.730425
Provenance
Creator Niewöhner, Christine; Hensen, Christian; Kasten, Sabine ORCID logo; Zabel, Matthias ORCID logo; Schulz, Horst D
Publisher PANGAEA
Publication Year 1998
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 4 datasets
Discipline Earth System Research
Spatial Coverage (10.998W, -25.518S, 13.230E, -17.160N); Northern Cape Basin
Temporal Coverage Begin 1996-01-31T00:00:00Z
Temporal Coverage End 1996-02-11T00:00:00Z