Lookup NU author(s): leanne Blake,
Dr Angela Sherry,
Dr Peter Leary,
Professor Ian Head,
Professor Neil Gray
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
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.
Author(s): Blake LI, Sherry A, Mejeha OK, Leary P, Coombs H, Stone W, Head IM, Gray ND
Publication type: Article
Publication status: Published
Online publication date: 24/09/2024
Acceptance date: 22/09/2020
Date deposited: 16/10/2020
ISSN (electronic): 2076-2607
Publisher: Multidisciplinary Digital Publishing Institute
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