Biological formation of ethane and propane in the deep marine subsurface

Authors

Kai-Uwe Hinrichs
John M. Hayes
Wolfgang Bach
Arthur J. Spivack, University of Rhode IslandFollow
Laura R. Hmelo
Nils G. Holm
Carl G. Johnson
Sean P. Sylva

Document Type

Article

Date of Original Version

2006

Department

Oceanography

Abstract

Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ. Reduction of acetate to ethane provides one feasible mechanism. Propane is enriched in ¹³C relative to ethane. The amount is consistent with derivation of the third C from inorganic carbon dissolved in sedimentary pore waters. At typical sedimentary conditions, the reactions yield free energy sufficient for growth. Relationships with competing processes are governed mainly by the abundance of H₂. Production of C₂ and C₃ hydrocarbons in this way provides a sink for acetate and hydrogen but upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.

Citation/Publisher Attribution

Hinrichs, K-U., Hayes, J. M., Bach, W., Spivack, A. J., Hmelo, L. R., Holm, N. G., Johnson, C. G., & Sylva, S. P. (2006). Biological formation of ethane and propane in the deep marine subsurface. PNAS, 103(40), 14684-14689. doi: 10.1073/pnas.0606535103

Available at: https://doi.org/10.1073/pnas.0606535103