An Unexpectedly Broad Thermal and Salinity-Tolerant Estuarine Methanogen Community

Blake, Lynsay I., Sherry, Angela, Mejeha, Obioma K., Leary, Peter, Coombs, Henry, Stone, Wendy, Head, Ian M. and Gray, Neil D. (2020) An Unexpectedly Broad Thermal and Salinity-Tolerant Estuarine Methanogen Community. Microorganisms, 8 (10). p. 1467. ISSN 2076-2607

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Moderately thermophilic (Tmax, ~55 °C) methanogens are identified after extended enrichments from temperate, tropical and low-temperature environments. However, thermophilic methanogens with higher growth temperatures (Topt ≥ 60 °C) are only reported from high-temperature environments. A microcosm-based approach was used to measure the rate of methane production and methanogen community structure over a range of temperatures and salinities in sediment from a temperate estuary. We report short-term incubations (<48 h) revealing methanogens with optimal activity reaching 70 °C in a temperate estuary sediment (in situ temperature 4–5 °C). While 30 °C enrichments amended with acetate, H2 or methanol selected for corresponding mesophilic trophic groups, at 60 °C, only hydrogenotrophs (genus Methanothermobacter) were observed. Since these methanogens are not known to be active under in situ temperatures, we conclude constant dispersal from high temperature habitats. The likely provenance of the thermophilic methanogens was studied by enrichments covering a range of temperatures and salinities. These enrichments indicated that the estuarine sediment hosted methanogens encompassing the global activity envelope of most cultured species. We suggest that estuaries are fascinating sink and source environments for microbial function study.

Item Type: Article
Uncontrolled Keywords: methanogenesis, methanogen community function, methanogen community structure
Subjects: C100 Biology
C500 Microbiology
C700 Molecular Biology, Biophysics and Biochemistry
Department: Faculties > Health and Life Sciences > Applied Sciences
Depositing User: Rachel Branson
Date Deposited: 08 Mar 2021 11:03
Last Modified: 31 Jul 2021 15:19

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