Nonequilibrium clumped isotope signals in microbial methane

Authors

David T. Wang, Massachusetts Institute of Technology
Danielle S. Gruen, Massachusetts Institute of Technology
Barbara Sherwood Lollar, University of Toronto
Kai Uwe Hinrichs, MARUM – Zen­trum für Ma­ri­ne Um­welt­wis­sen­schaf­ten
Lucy C. Stewart, University of Massachusetts Amherst
James F. Holden, University of Massachusetts Amherst
Alexander N. Hristov, Pennsylvania State University
John W. Pohlman, United States Geological Survey
Penny L. Morrill, Memorial University of Newfoundland
Martin Könneke, MARUM – Zen­trum für Ma­ri­ne Um­welt­wis­sen­schaf­ten
Kyle B. Delwiche, Massachusetts Institute of Technology
Eoghan P. Reeves, Massachusetts Institute of Technology
Chelsea N. Sutcliffe, University of Toronto
Daniel J. Ritter, The University of Arizona
Jeffrey S. Seewald, Woods Hole Oceanographic Institution
Jennifer C. McIntosh, The University of Arizona
Harold F. Hemond, Massachusetts Institute of Technology
Michael D. Kubo, NASA Ames Research Center
Dawn Cardace, University of Rhode Island
Tori M. Hoehler, NASA Ames Research Center
Shuhei Ono, Massachusetts Institute of Technology

Document Type

Article

Date of Original Version

4-24-2015

Abstract

Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, ¹³CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect of biological processes on methane's clumped isotopologue signature is poorly constrained.We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on ¹³CH3D abundances and results in anomalously elevated formation-temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

Publication Title, e.g., Journal

Science

Volume

348

Issue

6233

Citation/Publisher Attribution

Wang, David T., Danielle S. Gruen, Barbara Sherwood Lollar, Kai Uwe Hinrichs, Lucy C. Stewart, James F. Holden, Alexander N. Hristov, John W. Pohlman, Penny L. Morrill, Martin Könneke, Kyle B. Delwiche, Eoghan P. Reeves, Chelsea N. Sutcliffe, Daniel J. Ritter, Jeffrey S. Seewald, Jennifer C. McIntosh, Harold F. Hemond, Michael D. Kubo, Dawn Cardace, Tori M. Hoehler, and Shuhei Ono. "Nonequilibrium clumped isotope signals in microbial methane." Science 348, 6233 (2015). doi: 10.1126/science.aaa4326.