Sulphur and carbon isotopes as tracers of past sub-seafloor microbial activity
- Author(s)
- Patrick Meister, Benjamin Brunner, Aude Picard, Michael E. Böttcher, Bo Barker Jørgensen
- Abstract
Microbial life below the seafloor has changed over geological time, but these changes are often not obvious, as they are not recorded in the sediment. Sulphur (S) isotope values in pyrite extracted from a Plio- to Holocene sequence of the Peru Margin (Ocean Drilling Program, ODP, Site 1229) show a down-core pattern that correlates with the pattern of carbon (C) isotopes in diagenetic dolomite. Early formation of the pyrite is indicated by the mineralogical composition of iron, showing a high degree of pyritization throughout the sedimentary sequence. Hence, the S-record could not have been substantially overprinted by later pyrite formation. The S-and C-isotope profiles show, thus, evidence for two episodes of enhanced microbial methane production with a very shallow sulphate-methane transition zone. The events of high activity are correlated with zones of elevated organic C content in the stratigraphic sequence. Our results demonstrate how isotopic signatures preserved in diagenetic mineral phases provide information on changes of past biogeochemical activity in a dynamic sub-seafloor biosphere.
- Organisation(s)
- Department of Geology
- External organisation(s)
- University of Texas at El Paso, University of Nevada-Las Vegas, Leibniz-Institut für Ostseeforschung, Aarhus University, Max-Planck-Institut für marine Mikrobiologie
- Journal
- Scientific Reports
- Volume
- 9
- No. of pages
- 9
- ISSN
- 2045-2322
- DOI
- https://doi.org/10.1038/s41598-018-36943-7
- Publication date
- 01-2019
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105128 Geomicrobiology, 105105 Geochemistry
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/675b90cd-d87f-4d82-9dc8-112720383d28