Hinrichs Lab - C-Cascadia

C-Cascadia: Molecular-isotopic studies of subsurface carbon turnover in hydrate-bearing sediments at the Cascadia Margin (IODP Exp. 311)

Duration:	July 2006 - June 2008
Funding:	Deutsche Forschungsgemeinschaft (DFG) Schwerpunktprogramm 527 "Integrated Ocean Drilling Program/Ocean Drilling Program (IODP/ODP)" (Project HI 616/7-1)
Topics:	biomarker, deep biosphere
See also:	IODP, IODP Exp. 311

Principal Investigator:	Prof. Dr. Kai-Uwe Hinrichs
Involved Scientists in the Hinrichs Lab:	Dr. Verena Heuer
Partners:	Dr. T. Lorenson (U.S. Geological Survey, Coastal and Marine Geology Team, Menlo Park CA, USA), Dr. J.W. Pohlman (U.S. Geological Survey, Woods Hole Science Center, Woods Hole MA, USA), Prof. M.E. Torres (College of Oceanic and Atmospheric Sciences, Oregon State University, USA)

Abstract

In this project we investigated biogeochemical processes associated with the production and accumulation of methane in gas hydrate-bearing marine sediments at the northern Cascadia Margin. Anomalously high concentrations of dissolved inorganic and organic carbon in the large majority of gas hydrate provinces, in particular in methanogenic zones, suggest that some poorly constrained mechanism(s) enhance turnover of organic carbon in hydrate-bearing subsurface environments relative to non-hydrate systems in otherwise similar depositional settings. The project goal was to gain a better understanding of the biologically mediated carbon transformations that contribute to accumulation of methane in geologic time spans in hydrate-bearing sedimentary systems.

The focus of our attention was the pool of dissolved organic carbon; in particular we studied the compound-specific isotopic compositions of acetate and other volatile fatty acids, complemented by compound specific isotope information of intact membrane lipids that represent live subsurface prokaryotes. Together, these techniques provide insights into mechanisms of carbon turnover and carbon metabolism of subsurface prokaryotes.

Publications

Heuer, V.B., Pohlman, J.W., Torres, M.E., Elvert, M., Hinrichs, K.-U. (2009) The stable carbon isotope biogeochemistry of acetate and other dissolved carbon species in deep sub-seafloor sediments at the northern Cascadia Margin. Geochimica et Cosmochimica Acta, 73, 3323-3336. doi:10.1016/j.gca.2009.03.001

Pohlman, J.W., Kaneko, M., Heuer, V.B., Coffin, R.B., Whiticar, M. (2009) Methane sources and production in the northern Cascadia margin gas hydrate system. Earth and Planetary Science Letters, 287, 504-512. doi: 10.1016/j.epsl.2009.08.037

Technical Reports

Mienert, J., J. Parkes, B.B. Jørgensen, A. Boetius, P.A. Bjørkum, G. Bohrman, G. de Batist, G. Etiope, K. Kormas, V. Heuer, G. Aloisi, V. Diaz del Rio, and R. del Gaudio (2007) Biosphere-geosphere interactions: fluid flow and gas seepage at continental margins. In P. Cochonat et al. (eds) The Deep-Sea Frontier. Science challenges for a sustainable future. Office for Official Publications of the European Communities, Luxembourg, 16-23.

Riedel, M., Collett, T.S., Malone, M.J., and the Expedition 311 Scientists (2006) Proceedings of the Integrated Ocean Drilling Program, Volume 311. Washington, DC (Integrated Ocean Drilling Program Management International, Inc.) doi: 10.2204/iodp.proc.311.2006 [Cited 2007-12-21]

Riedel, M., T. Collett, M. Malone, F. Akiba, M. Blanc-Valleron, M. Ellis, G. Guerin, Y. Hashimoto, V. Heuer, Y. Higasi, M. Holland, P. Jackson, M. Kaneko, M. Kastner, J.-H. Kim, Kitajima, H., Long, P, Malinverno, A., Myers, G., Palekar, L., Pohlman, J., Schultheiss, P., B. Teichert, M.E. Torres, A. Tréhu, J.Wang, U. Wortmann, and H. Yoshioka (2006). Gas hydrate transect across northern Cascadia margin. Eos, Trans. Am. Geophys. Union, 87(33):325. doi:10.1029/2006EO330002.

Expedition 311 Scientists (2005) Cascadia margin gas hydrates. IODP Prel. Rept., 311. doi:10.2204/iodp.pr.311.2005