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| Titel |
Redox regime shifts in microbially mediated biogeochemical cycles |
| VerfasserIn |
T. Bush, I. B. Butler, A. Free, R. J. Allen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 12 ; Nr. 12, no. 12 (2015-06-17), S.3713-3724 |
| Datensatznummer |
250117989
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| Publikation (Nr.) |
 copernicus.org/bg-12-3713-2015.pdf |
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| Zusammenfassung |
| Understanding how the Earth's biogeochemical cycles respond to
environmental change is a prerequisite for the prediction and
mitigation of the effects of anthropogenic perturbations. Microbial
populations mediate key steps in these cycles, yet they are often crudely
represented in biogeochemical models. Here, we show that microbial
population dynamics can qualitatively affect the response of
biogeochemical cycles to environmental change. Using simple and
generic mathematical models, we find that nutrient limitations on
microbial population growth can lead to regime shifts, in which the
redox state of a biogeochemical cycle changes dramatically as the
availability of a redox-controlling species, such as oxygen or
acetate, crosses a threshold (a "tipping point"). These redox regime
shifts occur in parameter ranges that are relevant to the present-day sulfur
cycle in the natural environment and the present-day nitrogen cycle in eutrophic
terrestrial environments. These shifts may also
have relevance to iron cycling in the iron-containing Proterozoic and
Archean oceans. We show that redox regime shifts also occur in models
with physically realistic modifications, such as additional terms,
chemical states, or microbial populations. Our work reveals
a possible new mechanism by which regime shifts can occur in
nutrient-cycling ecosystems and biogeochemical cycles, and highlights
the importance of considering microbial population dynamics in models
of biogeochemical cycles. |
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