Manganese- and Iron-Dependent Marine Methane Oxidation
Emily J. Beal,1,*
Christopher H. House,1,*
Victoria J. Orphan2
Anaerobic methanotrophs help regulate Earth’s climate
and may have been an important part of the microbial ecosystem
on the early Earth. The anaerobic oxidation of methane (AOM)
is often thought of as a sulfate-dependent process, despite
the fact that other electron acceptors are more energetically
favorable. Here, we show that microorganisms from marine methane-seep
sediment in the Eel River Basin in California are capable of
using manganese (birnessite) and iron (ferrihydrite) to oxidize
methane, revealing that marine AOM is coupled, either directly
or indirectly, to a larger variety of oxidants than previously
thought. Large amounts of manganese and iron are provided to
oceans from rivers, indicating that manganese- and iron-dependent
AOM have the potential to be globally important.
2 Division of Geological and Planetary Sciences, Caltech, Pasadena, CA 91125, USA.
* To whom correspondence should be addressed. E-mail: ejbeal{at}gmail.com (E.J.B.); chrishouse{at}psu.edu (C.H.H.)
