7. Microbial Sulfate Reduction in Interstitial Waters from Sediments of the Southwest Pacific (Sites 1119-1124): Evidence from Stable Sulfur Isotopes¹

Michael E. Böttcher,² Boo-Keun Khim,³ and Atsushi Suzuki⁴

ABSTRACT

Seventy-nine interstitial water samples from six sites (Ocean Drilling Program Sites 1119-1124) from the southwestern Pacific Ocean have been analyzed for stable isotopes of dissolved sulfate (³⁴S), along with major and minor ions. Sulfate from the interstitial fluids (³⁴S values between +20.7 and +57.5 vs. the Vienna-Canyon Diablo troilite standard) was enriched in ³⁴S with respect to modern seawater (³⁴S +20.6), indicating that differing amounts of microbial sulfate reduction took place at all investigated sites. Microbial sulfate reduction was found at all sites, the intensity depending on the availability of organic matter, which is controlled by paleosedimentation conditions (e.g., sedimentation rate and presence of turbidites). In addition, total reduced inorganic sulfur (essentially pyrite) as a product of microbial sulfate reduction was quantified in selected sediments from Site 1119.

¹Böttcher, M.E., Khim, B.-K., and Suzuki, A., 2002. Microbial sulfate reduction in interstitial waters from sediments of the southwest Pacific (Sites 1119-1124): evidence from stable sulfur isotopes. In Richter, C. (Ed.), Proc. ODP, Sci. Results, 181 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/181_SR/201/201.htm>. [Cited YYYY-MM-DD]

²Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, D-28359 Bremen, Germany. mboettch@mpi-bremen.de

³Polar Science Laboratory, KORDI, Ansan 425-600, Korea.

⁴Geological Survey of Japan, Ibaraki 305-8567, Japan.

Initial receipt: 5 February 2001
Acceptance: 19 September 2001
Web publication: 21 February 2002
Ms 181SR-201