(Table 2) Concentrations and D/L values for three amino acids in bulk foraminifera from ODP Sites 182-1126 and 182-1127, supplement to: Mitterer, Richard M (2010): Methanogenesis and sulfate reduction in marine sediments: A new model. Earth and Planetary Science Letters, 295(3-4), 358-366

DOI

A number of studies have shown that methanogens are active in the presence of sulfate under some conditions. This phenomenon is especially exemplified in carbonate sediments of the southern Australian continental margin. Three sites cored during Ocean Drilling Program (ODP) Leg 182 in the Great Australian Bight have high concentrations of microbially-generated methane and hydrogen sulfide throughout almost 500 m of sediments. In these cores, the sulfate-reducing and methanogenic zones overlap completely; that is, the usual sulfate-methane transition zone is absent. Amino acid racemization data show that the gassy sediments consist of younger carbonates than the low-gas sites. High concentrations of the reduced gases also occur in two ODP sites on the margin of the Bahamas platform, both of which have similar sedimentary conditions to those of the high-gas sites of Leg 182. Co-generation of these reduced gases results from an unusual combination of conditions, including: (1) a thick Quaternary sequence of iron-poor carbonate sediments, (2) a sub-seafloor brine, and (3) moderate amounts of organic carbon. The probable explanation for the co-generation of hydrogen sulfide and methane in all these sites, as well as in other reported environments, is that methanogens are utilizing non-competitive substrates to produce methane within the sulfate-reducing zone. Taken together, these results form the basis of a new model for sulfate reduction and methanogenesis in marine sediments. The biogeochemical end-members of the model are: (1) minimal sulfate reduction, (2) complete sulfate reduction followed by methanogenesis, and (3) overlapping sulfate reduction and methanogenesis with no transition zone.

Identifier
DOI https://doi.org/10.1594/PANGAEA.786618
Related Identifier https://doi.org/10.1016/j.epsl.2010.04.009
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.786618
Provenance
Creator Mitterer, Richard M
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 2010
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Size 84 data points
Discipline Earth System Research
Spatial Coverage (128.067W, -33.509S, 128.481E, -33.357N); Great Australian Bight
Temporal Coverage Begin 1998-10-26T00:00:00Z
Temporal Coverage End 1998-11-03T00:00:00Z