Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input
Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon is...
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2021
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Online Access: | https://doi.org/10.3389/feart.2021.722215 https://doaj.org/article/0b9abcb7a6a44fa7965e8e6c0eaab13e |
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ftdoajarticles:oai:doaj.org/article:0b9abcb7a6a44fa7965e8e6c0eaab13e 2023-05-15T18:28:35+02:00 Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input Jonathan Schenk Henrique O. Sawakuchi Anna K. Sieczko Gustav Pajala David Rudberg Emelie Hagberg Kjell Fors Hjalmar Laudon Jan Karlsson David Bastviken 2021-10-01T00:00:00Z https://doi.org/10.3389/feart.2021.722215 https://doaj.org/article/0b9abcb7a6a44fa7965e8e6c0eaab13e EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.722215/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.722215 https://doaj.org/article/0b9abcb7a6a44fa7965e8e6c0eaab13e Frontiers in Earth Science, Vol 9 (2021) stable carbon isotope methane lake groundwater endmember Science Q article 2021 ftdoajarticles https://doi.org/10.3389/feart.2021.722215 2022-12-31T12:52:55Z Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions. Article in Journal/Newspaper Subarctic Directory of Open Access Journals: DOAJ Articles Methane Lake ENVELOPE(-114.168,-114.168,62.484,62.484) Frontiers in Earth Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
stable carbon isotope methane lake groundwater endmember Science Q |
spellingShingle |
stable carbon isotope methane lake groundwater endmember Science Q Jonathan Schenk Henrique O. Sawakuchi Anna K. Sieczko Gustav Pajala David Rudberg Emelie Hagberg Kjell Fors Hjalmar Laudon Jan Karlsson David Bastviken Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
topic_facet |
stable carbon isotope methane lake groundwater endmember Science Q |
description |
Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions. |
format |
Article in Journal/Newspaper |
author |
Jonathan Schenk Henrique O. Sawakuchi Anna K. Sieczko Gustav Pajala David Rudberg Emelie Hagberg Kjell Fors Hjalmar Laudon Jan Karlsson David Bastviken |
author_facet |
Jonathan Schenk Henrique O. Sawakuchi Anna K. Sieczko Gustav Pajala David Rudberg Emelie Hagberg Kjell Fors Hjalmar Laudon Jan Karlsson David Bastviken |
author_sort |
Jonathan Schenk |
title |
Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
title_short |
Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
title_full |
Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
title_fullStr |
Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
title_full_unstemmed |
Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input |
title_sort |
methane in lakes: variability in stable carbon isotopic composition and the potential importance of groundwater input |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/feart.2021.722215 https://doaj.org/article/0b9abcb7a6a44fa7965e8e6c0eaab13e |
long_lat |
ENVELOPE(-114.168,-114.168,62.484,62.484) |
geographic |
Methane Lake |
geographic_facet |
Methane Lake |
genre |
Subarctic |
genre_facet |
Subarctic |
op_source |
Frontiers in Earth Science, Vol 9 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.722215/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.722215 https://doaj.org/article/0b9abcb7a6a44fa7965e8e6c0eaab13e |
op_doi |
https://doi.org/10.3389/feart.2021.722215 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
_version_ |
1766211112521433088 |