Status: this preprint was under review for the journal BG. A revision for further review has not been submitted.
Rates and pathways of CH4 oxidation in ferruginous Lake Matano, Indonesia
A. Sturm,D. A. Fowle,C. Jones,K. Leslie,S. Nomosatryo,C. Henny,D. E. Canfield,and S. A. Crowe
Abstract. This study evaluates rates and pathways of methane (CH4) oxidation and uptake using 14C-based tracer experiments throughout the oxic and anoxic waters of ferruginous Lake Matano. Methane oxidation rates in Lake Matano are low compared to other lakes, but are sufficiently high to preclude strong CH4 fluxes to the atmosphere. In addition to aerobic CH4 oxidation, which takes place in Lake Matano's oxic mixolimnion, we also detected CH4 oxidation in Lake Matano's anoxic ferruginous waters. Here, CH4 oxidation proceeds in the apparent absence of oxygen (O2) and instead appears to be coupled to nitrate (NO3−), nitrite (NO2−), iron (Fe), or manganese (Mn) reduction. Throughout the lake, the fraction of CH4 carbon that is assimilated vs. oxidized to carbon dioxide (CO2) is high, indicating extensive CH4 conversion to biomass and underscoring the importance of CH4 as a carbon and energy source in Lake Matano and potentially other ferruginous or low productivity environments.
Received: 14 Oct 2015 – Discussion started: 22 Feb 2016
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Department of Geology, University of Kansas, Lawrence KS 66047, USA
D. A. Fowle
Department of Geology, University of Kansas, Lawrence KS 66047, USA
C. Jones
Department of Microbiology and Immunology and Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
Nordic Center for Earth Evolution, Institute of Biology, Univ. of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
K. Leslie
Department of Geology, University of Kansas, Lawrence KS 66047, USA
S. Nomosatryo
Research Center for Limnology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor, Indonesia
C. Henny
Research Center for Limnology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor, Indonesia
D. E. Canfield
Nordic Center for Earth Evolution, Institute of Biology, Univ. of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
S. A. Crowe
Department of Microbiology and Immunology and Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada
Nordic Center for Earth Evolution, Institute of Biology, Univ. of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
Methane is a very potent greenhouse gas whose release into the atmosphere has become a growing concern for global climate change. In nearly every aquatic environment there are microbes which either produce methane as a by-product of their metabolism or consume it for energy. Our work examined the rates of methane consumption through experimentation in a deep tropical lake to help quantify global emissions of this greenhouse gas from these environments and provide context for paleo-carbon cycles.
Methane is a very potent greenhouse gas whose release into the atmosphere has become a growing...