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Factors governing methane oxidation pathways at redox boundaries in lakes

English title Factors governing methane oxidation pathways at redox boundaries in lakes
Applicant Wehrli Bernhard
Number 153091
Funding scheme Project funding (Div. I-III)
Research institution Abteilung Oberflächengewässer EAWAG
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Hydrology, Limnology, Glaciology
Start/End 01.04.2014 - 31.03.2016
Approved amount 259'730.00
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All Disciplines (3)

Discipline
Hydrology, Limnology, Glaciology
Geochemistry
Other disciplines of Environmental Sciences

Keywords (9)

micronutrients; isotopes; sensors; oxidation; methanotrophs; copper; iron; lake; Nano SIMS

Lay Summary (German)

Lead
Das Treibhausgas Methan wird in Sedimenten von Seen gebildet, weil diese einen hohen Anteil an leicht abbaubarer Biomasse aufweisen und weil dort ab wenigen Millimetern Tiefe kaum mehr Sauerstoff vorhanden ist. Im Seewasser dagegen wird gelöstes Methan von spezialisierten Bakterien oxidiert. Dieser wichtige Prozess vermindert die Emission in die Atmosphäre. Die Abbauwege von Methan in Seen werden in diesem Projekt im Detail untersucht um den Einfluss von unterschiedlichen Oxidationsmitteln und von Spurenmetallen wie Kupfer und Eisen auf diesen Prozess zu identifizieren. Wir setzen eine Kombination verschiedener Beobachtungsmethoden ein: Sensortechnik, Massenspektrometrie an einzelnen Zellen und Experimente mit Isotopentracern. Die Feldarbeit findet an geschichteten Seen in der Schweiz, in Spanien, in Zentralafrika und Kanada statt.
Lay summary

The greenhouse gas methane is produced in lake sediments. These systems typically contain a large fraction of labile organic carbon but oxygen is usually absent below a few millimeters of sediment depth. In the water column of lakes, however, methane is oxidized by specialized bacteria, which prevent out gassing to the atmosphere. The oxidation pathways of methane at the redox boundaries of lakes will be studied in this project in order to identify the role of different oxidation agents and of the two main trace nutrients copper and iron which are important for the biochemistry of methane oxidizing bacteria. We combine different methodologies such as sensor technologies, mass spectrometry on single cells and experiments with isotopic tracers. Our main field sites are stratified lakes in Switzerland, Spain, Central Africa and in Canada.

 

Direct link to Lay Summary Last update: 13.05.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
Methanotrophy under versatile conditions in the water column of the ferruginous meromictic Lake La Cruz (Spain)
Oswald Kirsten, Jegge Corinne, Tischer Jana, Berg Jasmin, Brand Andreas, Miracle Maria, Soria Xavier, Vicente Eduarado, Lehmann Moritz, Zopfi J, Schubert Carsten (2016), Methanotrophy under versatile conditions in the water column of the ferruginous meromictic Lake La Cruz (Spain), in Frontiers in Microbiology, 7(1762), 1-16.
Variable mehanotrophy at the oxycline and in the anoxic waters of a meromictic lake
Oswald Kirsten, Milucka Jana, Brand Andreas, Hach Philipp, Littmann Sten, Wehrli Bernhard, Kuypers Marcel, Schubert Carsten (2016), Variable mehanotrophy at the oxycline and in the anoxic waters of a meromictic lake, in Limnology and Oceanography, 61, S101-S118.
Oxygen primay production below the oxycline and its importance for redox dynamics
Brand Andreas, Bruderer Hanna, Oswald Kirsten, Schubert Carsten, Wehrli Bernhard, Guggenheim Carole (2016), Oxygen primay production below the oxycline and its importance for redox dynamics, in Aquatic Sciences, 10.1007/s0.
Light-dependent aerobic methane oxidation reduces methane emissions from seasonally stratified lakes.
Oswald Kirsten, Milucka Jana, Brand Andreas, Wehrli Bernhard, Kuypers Marcel, Schubert Carsten (2015), Light-dependent aerobic methane oxidation reduces methane emissions from seasonally stratified lakes., in PLOS ONE, 10(7), e0132574.
Molecular and isotopic insights into methane oxidation and associated methanotrophic communities in the water column of a tropical lake (Lake Kivu).
Zigah Prosper, Oswald Kirsten, Brand Andreas, Dinkel Christian, Wehrli Bernhard, Schubert Carsten (2015), Molecular and isotopic insights into methane oxidation and associated methanotrophic communities in the water column of a tropical lake (Lake Kivu)., in Limnology and Oceanography, 60, 553-572.
Crenotrhix are major methane consumers in stratified lakes
Oswald Kirsten, Graf Jon, Littmann Sten, Tienken Daniela, Brand Andreas, Wehrli Bernhard, Abertsen Mads, Daims Holger, Wagner Michael, Crenotrhix are major methane consumers in stratified lakes, in The ISME Journal.
Oxygen primay production below the oxycline and its importance for redox cycling
Brand Andreas, Bruderer Hanna, Oswald Kirsten, Schubert Carsten, Wehrli Bernhard, Guggenheim Carole, Oxygen primay production below the oxycline and its importance for redox cycling, in Aquatic Sciences, 10.1007/s0.

Collaboration

Group / person Country
Types of collaboration
Dr. Jakob Zopfi, Univ. Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. Marcel Kuypers, MPI Bremen Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Prof. Laura Sigg, Eawag Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Goldschmidt Conference Talk given at a conference Light-dependent aerobic methane oxidation reduces methane emissions from seasonally stratified lakes 20.08.2015 Prague, Czech Republic Wehrli Bernhard; Schubert Carsten; Oswald Kirsten Joan;
ASLO Aquatic Sciences Meeting Talk given at a conference Emissions from stratified lakes reduced by light-dependent aerobivc methane oxidation 22.02.2015 Granada, Spain Schubert Carsten; Wehrli Bernhard; Oswald Kirsten Joan;
NanoSIMS International Workshop Poster Methane emissions reduced by light-dependent aerobic oxidation 13.10.2014 Paris, France Schubert Carsten; Wehrli Bernhard; Oswald Kirsten Joan;
ISEAC38 Conference Poster In-situ trace metal speciation in the habitat of methanotrophs 17.06.2014 Lausanne, Switzerland Wehrli Bernhard; Guggenheim Carole Selma;


Awards

Title Year
ETH Medaille 2017

Associated projects

Number Title Start Funding scheme
135299 Methane oxidation pathways at oxic-anoxic boundaries in lakes 01.04.2011 Project funding (Div. I-III)
128707 High resolution in situ nutrient mapping of large rivers and reservoir systems 01.04.2010 R'EQUIP
157750 Cluster of sondes for the high-resolution analysis of aquatic ecosystems 01.12.2014 R'EQUIP

Abstract

Methane emissions from lakes and reservoirs to the atmosphere could contribute up to 8% to the atmospheric flux and should be included in the global CH4 budget. Emission rates from freshwater systems are poorly constrained be-cause methane is produced at highly variable rates, it can be oxidized in the sediment and in the water column, and transferred to the atmosphere either by diffusion or by rising bubbles.Methanotrophic bacteria prefer O2 as an electron acceptor, but several new pathways of methane oxidation in the absence of oxygen have been recently discovered: Microbial methane oxidation can also proceed via reduction of nitrate, nitrite, iron- and manganese oxides. The anaerobic methane oxidation pathway via sulfate reduction has been firmly established for marine systems. The new, alternative pathways could stabilize methane oxidation rates under fluctuating oxygen conditions at redox boundaries in lakes. They could also extend the depth interval in which methane oxidation is occurring when oxygen disappears in stratified lakes or at the sediment-water interface. The factors governing methane oxidation pathways under natural conditions are to a large extend unknown, because most evidence for alternative electron acceptors is based on laboratory incubations. One of the potential controlling factors for methanotrophic communities has been studied extensively under controlled conditions: The two different enzymes for the oxidation of CH4 with O2 need copper and iron as micro-nutrients. The availability of these trace metals in the critical zone could therefore trigger changes in the oxidation pathways but has not yet been systematically investigated under natural conditions.The ongoing project provided new insights into the role of oxygenic phototrophs and the manganese cycle for methane oxidation. With this proposed 2-year continuation we will address the following research questions:•Which pathways of methane oxidation are operating at different redox environments in lakes and which fraction of methane is transformed by different electron acceptors?•Which factors such as the concentrations and fluxes of methane, electron acceptors and micronutrients are governing the oxidation pathways of methane?•What are the consequences of coupled redox cascades such as oxygenic phototrophs or the manganese redox cycle for the overall methane oxidation, its isotopic signature and for dark microbial production?We propose to extend our ongoing field studies in five stratified lakes in Switzerland, Spain, Central Africa and West-ern Canada with contrasting boundary conditions. They differ in the availability of methane and electron acceptors, the vertical mixing regime and the seasonality of redox cycling. Our biogeochemical analysis combines our expertise in high-resolution profiling and sampling techniques, the analysis of stable isotopes and in-situ reaction rates, and the know-how in reaction-transport modeling of the water column in physically well-characterized lake systems. By focusing on consistent biogeochemical analysis of methane oxidation across several systems the project aims at providing general insights and reference data for improved global estimates.
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