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CC BY V4.0, Open Access
Journal article
Impact of Electron Acceptor Availability on Methane-Influenced Microorganisms in an Enrichment Culture Obtained From a Stratified Lake
Frontiers in microbiology, Vol.11(11), pp.715-715
05/14/2020
PMID: 32477281
Abstract
Methanotrophs are of major importance in limiting methane emissions from lakes. They are known to preferably inhabit the oxycline of stratified water columns, often assumed due to an intolerance to atmospheric oxygen concentrations, but little is known on the response of methanotrophs to different oxygen concentrations as well as their preference for different electron acceptors. In this study, we enriched a methanotroph of theMethylobactergenus from the oxycline and the anoxic water column of a stratified lake, which was also present in the oxic water column in the winter. We tested the response of thisMethylobacter-dominated enrichment culture to different electron acceptors, i.e., oxygen, nitrate, sulfate, and humic substances, and found that, in contrast to earlier results with water column incubations, oxygen was the preferred electron acceptor, leading to methane oxidation rates of 45-72 pmol cell(-1)day(-1). Despite the general assumption of methanotrophs preferring microaerobic conditions, methane oxidation was most efficient under high oxygen concentrations (>600 mu M). Low (<30 mu M) oxygen concentrations still supported methane oxidation, but no methane oxidation was observed with trace oxygen concentrations (<9 mu M) or under anoxic conditions. Remarkably, the presence of nitrate stimulated methane oxidation rates under oxic conditions, raising the methane oxidation rates by 50% when compared to oxic incubations with ammonium. Under anoxic conditions, no net methane consumption was observed; however, methanotroph abundances were two to three times higher in incubations with nitrate and sulfate compared to anoxic incubations with ammonium as the nitrogen source. Metagenomic sequencing revealed the absence of a complete denitrification pathway in the dominant methanotrophMethylobacter, but the most abundant methylotrophMethyloteneraseemed capable of denitrification, which can possibly play a role in the enhanced methane oxidation rates under nitrate-rich conditions.
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Details
- Title
- Impact of Electron Acceptor Availability on Methane-Influenced Microorganisms in an Enrichment Culture Obtained From a Stratified Lake
- Creators
- Sigrid van Grinsven - Royal Netherlands Institute for Sea ResearchJaap S. Sinninghe Damste - Utrecht UniversityJohn Harrison - Washington State University, Environment, School of the (CAS)Laura Villanueva - Utrecht University
- Publication Details
- Frontiers in microbiology, Vol.11(11), pp.715-715
- Academic Unit
- Environment, School of the (CAS); Harrison Research Group: Global Change and Watershed Biochemistry
- Publisher
- FRONTIERS MEDIA SA
- Number of pages
- 14
- Grant note
- Netherlands Ministry of Education, Culture and Science (OCW) Netherlands Organisation for Scientific Research (NWO) 024.002.002 / Soehngen Institute of Anaerobic Microbiology (SIAM) Gravitation grant
- Identifiers
- 99900667383801842
- Language
- English
- Resource Type
- Journal article