Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno
Although lake sediments are globally important organic carbon sinks and therefore important habitats for deep microbial life, the deep lacustrine biosphere has thus far been little studied compared to its marine counterpart. To investigate the impact of the underexplored deep lacustrine biosphere on...
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| Format: | Article |
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Frontiers Media S.A.
2022-01-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2021.754888/full |
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| author | Jasmine S. Berg Mathilde Lepine Emile Laymand Xingguo Han Hendrik Vogel Marina A. Morlock Niroshan Gajendra Adrian Gilli Stefano M. Bernasconi Carsten J. Schubert Carsten J. Schubert Guangyi Su Mark A. Lever |
| author_facet | Jasmine S. Berg Mathilde Lepine Emile Laymand Xingguo Han Hendrik Vogel Marina A. Morlock Niroshan Gajendra Adrian Gilli Stefano M. Bernasconi Carsten J. Schubert Carsten J. Schubert Guangyi Su Mark A. Lever |
| author_sort | Jasmine S. Berg |
| collection | DOAJ |
| description | Although lake sediments are globally important organic carbon sinks and therefore important habitats for deep microbial life, the deep lacustrine biosphere has thus far been little studied compared to its marine counterpart. To investigate the impact of the underexplored deep lacustrine biosphere on the sediment geochemical environment and vice versa, we performed a comprehensive microbiological and geochemical characterization of a sedimentary sequence from Lake Cadagno covering its entire environmental history since formation following glacial retreat. We found that both geochemical gradients and microbial community shifts across the ∼13.5 kyr subsurface sedimentary record reflect redox changes in the lake, going from oxic to anoxic and sulfidic. Most microbial activity occurs within the top 20 cm of sediment, where millimolar sulfate concentrations diffusing in from the bottom water are almost completely consumed. In deeper sediment layers, organic carbon remineralization is much slower but microorganisms nonetheless subsist on fermentation, sulfur cycling, metal reduction, and methanogenesis. The most surprising finding was the presence of a deep, oxidizing groundwater source. This water source generates an inverse redox gradient at the bottom of the sedimentary sequence and could contribute to the remineralization of organic matter sequestered in the energy-limited deep subsurface. |
| first_indexed | 2024-04-13T08:50:52Z |
| format | Article |
| id | doaj.art-4981f7317aec4a55ac0280d49f09a98d |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-13T08:50:52Z |
| publishDate | 2022-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-4981f7317aec4a55ac0280d49f09a98d2022-12-22T02:53:29ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-01-01910.3389/feart.2021.754888754888Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake CadagnoJasmine S. Berg0Mathilde Lepine1Emile Laymand2Xingguo Han3Hendrik Vogel4Marina A. Morlock5Niroshan Gajendra6Adrian Gilli7Stefano M. Bernasconi8Carsten J. Schubert9Carsten J. Schubert10Guangyi Su11Mark A. Lever12Department of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandInstitute of Geological Sciences, University of Bern, Bern, SwitzerlandInstitute of Geological Sciences, University of Bern, Bern, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandDepartment of Earth Sciences, ETH-Zurich, Zurich, SwitzerlandDepartment of Earth Sciences, ETH-Zurich, Zurich, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandSurface Waters-Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, SwitzerlandSurface Waters-Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, SwitzerlandDepartment of Environmental Systems Science, ETH-Zurich, Zurich, SwitzerlandAlthough lake sediments are globally important organic carbon sinks and therefore important habitats for deep microbial life, the deep lacustrine biosphere has thus far been little studied compared to its marine counterpart. To investigate the impact of the underexplored deep lacustrine biosphere on the sediment geochemical environment and vice versa, we performed a comprehensive microbiological and geochemical characterization of a sedimentary sequence from Lake Cadagno covering its entire environmental history since formation following glacial retreat. We found that both geochemical gradients and microbial community shifts across the ∼13.5 kyr subsurface sedimentary record reflect redox changes in the lake, going from oxic to anoxic and sulfidic. Most microbial activity occurs within the top 20 cm of sediment, where millimolar sulfate concentrations diffusing in from the bottom water are almost completely consumed. In deeper sediment layers, organic carbon remineralization is much slower but microorganisms nonetheless subsist on fermentation, sulfur cycling, metal reduction, and methanogenesis. The most surprising finding was the presence of a deep, oxidizing groundwater source. This water source generates an inverse redox gradient at the bottom of the sedimentary sequence and could contribute to the remineralization of organic matter sequestered in the energy-limited deep subsurface.https://www.frontiersin.org/articles/10.3389/feart.2021.754888/fulllake sedimentsdeep biospherebacteriaarchaearedox gradients |
| spellingShingle | Jasmine S. Berg Mathilde Lepine Emile Laymand Xingguo Han Hendrik Vogel Marina A. Morlock Niroshan Gajendra Adrian Gilli Stefano M. Bernasconi Carsten J. Schubert Carsten J. Schubert Guangyi Su Mark A. Lever Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno Frontiers in Earth Science lake sediments deep biosphere bacteria archaea redox gradients |
| title | Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno |
| title_full | Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno |
| title_fullStr | Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno |
| title_full_unstemmed | Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno |
| title_short | Ancient and Modern Geochemical Signatures in the 13,500-Year Sedimentary Record of Lake Cadagno |
| title_sort | ancient and modern geochemical signatures in the 13 500 year sedimentary record of lake cadagno |
| topic | lake sediments deep biosphere bacteria archaea redox gradients |
| url | https://www.frontiersin.org/articles/10.3389/feart.2021.754888/full |
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