Understanding Ferruginous Versus Euxinic Conditions by Simulating Microbial Conditions in Meromictic Lakes.
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| Title: | Understanding Ferruginous Versus Euxinic Conditions by Simulating Microbial Conditions in Meromictic Lakes. |
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| Authors: | Hawkins, Vanessa M.1 (AUTHOR) hawkinsv@oregonstate.edu, Sheik, Cody S.2,3 (AUTHOR), Katsev, Sergei1,3 (AUTHOR) skatsev@d.umn.edu |
| Source: | Geobiology. Sep/Oct2025, Vol. 23 Issue 5, p1-13. 13p. |
| Subject Terms: | *Biogeochemistry, *Microbial ecology, *Lakes, *Methane, *Sulfate-reducing bacteria, *Anaerobic bacteria |
| Abstract: | Ferruginous (iron‐rich) conditions have been prominent in oceans throughout the Earth's geologic history but now are reliably found only in a handful of permanently stratified lakes. Microbially mediated iron reduction in such anoxic environments competes with sulfate reduction, which promotes euxinic (sulfide‐rich) conditions. Besides the shared demand for organic compounds, the competition is fostered by the produced hydrogen sulfide, which may reduce iron oxides abiotically or co‐precipitate with dissolved iron as iron sulfides. Understanding why some environments develop ferruginous rather than euxinic conditions (or vice versa), as well as the attendant effects on methanogenic fermentation, is key to understanding both modern and ancient anoxic ecosystems. Here, we reproduce biogeochemical distributions in multiple anoxic, low‐sulfate, meromictic lakes around the world using a biomass‐explicit reaction‐transport model with a fixed set of metabolism‐specific microbial parameters. The results suggest that sulfate reduction and methanogenesis are ubiquitous even in iron‐rich systems, and are reflected in microbial surveys. Ferruginous conditions typically develop for surface sulfate concentrations below ≃100 μM. Interestingly, there seems to be a dearth of stably stratified water bodies where sulfate concentrations can persist in the medium‐sulfate range of several hundred μM. Rather, when sulfur burial into the sediments becomes iron limited, sulfate tends to accumulate in the water column to much higher (mM) concentrations. A similar mechanism could be suggested to have operated in the variably sulfidic and ferruginous water columns of early oceans. Model simulations also reveal the previously underappreciated role of physical transport in shaping biogeochemical distributions, as minor variations in mixing rates can lead to large variations in microbial abundances. Model applicability across multiple lakes points to an encouraging possibility that geochemical patterns in complex biogeochemical systems may be described from a small number of thermodynamic and kinetic principles using a minimum of fitting parameters. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: enr DbLabel: Energy & Power Source An: 188860496 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Understanding Ferruginous Versus Euxinic Conditions by Simulating Microbial Conditions in Meromictic Lakes. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Hawkins%2C+Vanessa+M%2E%22">Hawkins, Vanessa M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> hawkinsv@oregonstate.edu</i><br /><searchLink fieldCode="AR" term="%22Sheik%2C+Cody+S%2E%22">Sheik, Cody S.</searchLink><relatesTo>2,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Katsev%2C+Sergei%22">Katsev, Sergei</searchLink><relatesTo>1,3</relatesTo> (AUTHOR)<i> skatsev@d.umn.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geobiology%22">Geobiology</searchLink>. Sep/Oct2025, Vol. 23 Issue 5, p1-13. 13p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Biogeochemistry%22">Biogeochemistry</searchLink><br />*<searchLink fieldCode="DE" term="%22Microbial+ecology%22">Microbial ecology</searchLink><br />*<searchLink fieldCode="DE" term="%22Lakes%22">Lakes</searchLink><br />*<searchLink fieldCode="DE" term="%22Methane%22">Methane</searchLink><br />*<searchLink fieldCode="DE" term="%22Sulfate-reducing+bacteria%22">Sulfate-reducing bacteria</searchLink><br />*<searchLink fieldCode="DE" term="%22Anaerobic+bacteria%22">Anaerobic bacteria</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Ferruginous (iron‐rich) conditions have been prominent in oceans throughout the Earth's geologic history but now are reliably found only in a handful of permanently stratified lakes. Microbially mediated iron reduction in such anoxic environments competes with sulfate reduction, which promotes euxinic (sulfide‐rich) conditions. Besides the shared demand for organic compounds, the competition is fostered by the produced hydrogen sulfide, which may reduce iron oxides abiotically or co‐precipitate with dissolved iron as iron sulfides. Understanding why some environments develop ferruginous rather than euxinic conditions (or vice versa), as well as the attendant effects on methanogenic fermentation, is key to understanding both modern and ancient anoxic ecosystems. Here, we reproduce biogeochemical distributions in multiple anoxic, low‐sulfate, meromictic lakes around the world using a biomass‐explicit reaction‐transport model with a fixed set of metabolism‐specific microbial parameters. The results suggest that sulfate reduction and methanogenesis are ubiquitous even in iron‐rich systems, and are reflected in microbial surveys. Ferruginous conditions typically develop for surface sulfate concentrations below ≃100 μM. Interestingly, there seems to be a dearth of stably stratified water bodies where sulfate concentrations can persist in the medium‐sulfate range of several hundred μM. Rather, when sulfur burial into the sediments becomes iron limited, sulfate tends to accumulate in the water column to much higher (mM) concentrations. A similar mechanism could be suggested to have operated in the variably sulfidic and ferruginous water columns of early oceans. Model simulations also reveal the previously underappreciated role of physical transport in shaping biogeochemical distributions, as minor variations in mixing rates can lead to large variations in microbial abundances. Model applicability across multiple lakes points to an encouraging possibility that geochemical patterns in complex biogeochemical systems may be described from a small number of thermodynamic and kinetic principles using a minimum of fitting parameters. [ABSTRACT FROM AUTHOR] |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1111/gbi.70037 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 13 StartPage: 1 Subjects: – SubjectFull: Biogeochemistry Type: general – SubjectFull: Microbial ecology Type: general – SubjectFull: Lakes Type: general – SubjectFull: Methane Type: general – SubjectFull: Sulfate-reducing bacteria Type: general – SubjectFull: Anaerobic bacteria Type: general Titles: – TitleFull: Understanding Ferruginous Versus Euxinic Conditions by Simulating Microbial Conditions in Meromictic Lakes. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Hawkins, Vanessa M. – PersonEntity: Name: NameFull: Sheik, Cody S. – PersonEntity: Name: NameFull: Katsev, Sergei IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 09 Text: Sep/Oct2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 14724677 Numbering: – Type: volume Value: 23 – Type: issue Value: 5 Titles: – TitleFull: Geobiology Type: main |
| ResultId | 1 |
