Franziska Koebsch, Matthias Winkel, Susanne Liebner, Bo Liu, Julia Westphal, Iris Schmiedinger, Alejandro Spitzy, Matthias Gehre, Gerald Jurasinski, Stefan Köhler, Viktoria Unger, Marian Koch, Torsten Sachs, Michael E. Böttcher
- In natural coastal wetlands, high supplies of marine sulfate suppress methanogenesis. Coastal wetlands are, however, often subject to disturbance by diking and drainage for agricultural use and can turn to potent methane sources when rewetted for remediation. This suggests that preceding land use measures can suspend the sulfate-related methane suppressing mechanisms. Here, we unravel the hydrological relocation and biogeochemical S and C transformation processes that induced high methane emissions in a disturbed and rewetted peatland despite former brackish impact. The underlying processes were investigated along a transect of increasing distance to the coastline using a combination of concentration patterns, stable isotope partitioning, and analysis of the microbial community structure. We found that diking and freshwater rewetting caused a distinct freshening and an efficient depletion of the brackish sulfate reservoir by dissimilatory sulfate reduction (DSR). Despite some legacy effects of brackish impact expressed as high amountsIn natural coastal wetlands, high supplies of marine sulfate suppress methanogenesis. Coastal wetlands are, however, often subject to disturbance by diking and drainage for agricultural use and can turn to potent methane sources when rewetted for remediation. This suggests that preceding land use measures can suspend the sulfate-related methane suppressing mechanisms. Here, we unravel the hydrological relocation and biogeochemical S and C transformation processes that induced high methane emissions in a disturbed and rewetted peatland despite former brackish impact. The underlying processes were investigated along a transect of increasing distance to the coastline using a combination of concentration patterns, stable isotope partitioning, and analysis of the microbial community structure. We found that diking and freshwater rewetting caused a distinct freshening and an efficient depletion of the brackish sulfate reservoir by dissimilatory sulfate reduction (DSR). Despite some legacy effects of brackish impact expressed as high amounts of sedimentary S and elevated electrical conductivities, contemporary metabolic processes operated mainly under sulfate-limited conditions. This opened up favorable conditions for the establishment of a prospering methanogenic community in the top 30-40 cm of peat, the structure and physiology of which resemble those of terrestrial organic-rich environments. Locally, high amounts of sulfate persisted in deeper peat layers through the inhibition of DSR, probably by competitive electron acceptors of terrestrial origin, for example Fe(III). However, as sulfate occurred only in peat layers below 30-40 cm, it did not interfere with high methane emissions on an ecosystem scale. Our results indicate that the climate effect of disturbed and remediated coastal wetlands cannot simply be derived by analogy with their natural counterparts. From a greenhouse gas perspective, the re-exposure of diked wetlands to natural coastal dynamics would literally open up the floodgates for a replenishment of the marine sulfate pool and therefore constitute an efficient measure to reduce methane emissions.…
MetadatenAuthor details: | Franziska KoebschGND, Matthias WinkelORCiDGND, Susanne LiebnerORCiDGND, Bo LiuORCiD, Julia Westphal, Iris Schmiedinger, Alejandro Spitzy, Matthias GehreORCiD, Gerald JurasinskiORCiD, Stefan Köhler, Viktoria UngerORCiD, Marian Koch, Torsten SachsORCiDGND, Michael E. BöttcherORCiD |
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DOI: | https://doi.org/10.5194/bg-16-1937-2019 |
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ISSN: | 1726-4170 |
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ISSN: | 1726-4189 |
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Title of parent work (English): | Biogeosciences |
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Publisher: | Copernicus |
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Place of publishing: | Göttingen |
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Publication type: | Article |
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Language: | English |
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Date of first publication: | 2019/05/13 |
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Publication year: | 2019 |
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Release date: | 2021/02/11 |
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Volume: | 16 |
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Issue: | 9 |
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Number of pages: | 17 |
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First page: | 1937 |
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Last Page: | 1953 |
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Funding institution: | DFG Research Training Group BALTIC TRANSCOASTGerman Research Foundation (DFG) [DFG GRK 2000]; Helmholtz Terrestrial Environmental Observatories (TERENO) Network; BALTIC TRANSCOAST [GRK2000/0023]; Helmholtz Association of German Research Centers through the Helmholtz Postdoc Program [PD-129]; Helmholtz Climate Initiative REKLIM (Regional Climate Change); European Social Fund (ESF)European Social Fund (ESF) [ESF/14-BM-A55-0030/16]; Ministry of Education, Science and Culture of Mecklenburg-West Pomerania within the scope of the project WETSCAPES [ESF/14-BM-A55-0030/16]; Helmholtz Young Investigators Group [VH-NG-821, VH-NG-919]; Leibniz Institute for Baltic Sea Research (IOW); Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG); Universitat Rostock |
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Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie |
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DDC classification: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
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Peer review: | Referiert |
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Publishing method: | Open Access / Gold Open-Access |
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| DOAJ gelistet |
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License (German): | CC-BY - Namensnennung 4.0 International |
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