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Increases in temperature and nutrient availability positively affect methane‐cycling microorganisms in Arctic thermokarst lake sediments
Author(s) -
de Jong Anniek E. E.,
in ’t Zandt Michiel H.,
Meisel Ove H.,
Jetten Mike S. M.,
Dean Joshua F.,
Rasigraf Olivia,
Welte Cornelia U.
Publication year - 2018
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14345
Subject(s) - thermokarst , environmental chemistry , permafrost , methane , microbial population biology , arctic , nutrient cycle , anaerobic oxidation of methane , nitrate , microorganism , methanogen , carbon cycle , methanotroph , nutrient , ecology , biology , ecosystem , chemistry , bacteria , genetics
Summary Arctic permafrost soils store large amounts of organic matter that is sensitive to temperature increases and subsequent microbial degradation to methane (CH 4 ) and carbon dioxide (CO 2 ). Here, we studied methanogenic and methanotrophic activity and community composition in thermokarst lake sediments from Utqiag˙vik (formerly Barrow), Alaska. This experiment was carried out under in situ temperature conditions (4°C) and the IPCC 2013 Arctic climate change scenario (10°C) after addition of methanogenic and methanotrophic substrates for nearly a year. Trimethylamine (TMA) amendment with warming showed highest maximum CH 4 production rates, being 30% higher at 10°C than at 4°C. Maximum methanotrophic rates increased by up to 57% at 10°C compared to 4°C. 16S rRNA gene sequencing indicated high relative abundance of Methanosarcinaceae in TMA amended incubations, and for methanotrophic incubations Methylococcaeae were highly enriched. Anaerobic methanotrophic activity with nitrite or nitrate as electron acceptor was not detected. This study indicates that the methane cycling microbial community can adapt to temperature increases and that their activity is highly dependent on substrate availability.