Biogeochemical Activity of Methane-Related Microbial Communities in Bottom Sediments of Cold Seeps of the Laptev Sea

Bottom sediments at methane discharge sites of the Laptev Sea shelf were investigated. The rates of microbial methanogenesis and methane oxidation were measured, and the communities responsible for these processes were analyzed. Methane content in the sediments varied from 0.9 to 37 µmol CH 4 dm −3...

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Bibliographic Details
Published in:Microorganisms
Main Authors: Alexander S. Savvichev, Igor I. Rusanov, Vitaly V. Kadnikov, Alexey V. Beletsky, Elena E. Zakcharova, Olga S. Samylina, Pavel A. Sigalevich, Igor P. Semiletov, Nikolai V. Ravin, Nikolay V. Pimenov
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2023
Subjects:
Laptev Sea
marine sediments
cold methane seep
microbial community
rates of microbial processes
carbon stable isotope
Biology (General)
QH301-705.5
laptev
Online Access:https://doi.org/10.3390/microorganisms11020250
https://doaj.org/article/ae1bde84fd8a43c7ae6ccd83df2b2d3c
Description
Summary:Bottom sediments at methane discharge sites of the Laptev Sea shelf were investigated. The rates of microbial methanogenesis and methane oxidation were measured, and the communities responsible for these processes were analyzed. Methane content in the sediments varied from 0.9 to 37 µmol CH 4 dm −3 . Methane carbon isotopic composition (δ 13 C-CH 4 ) varied from −98.9 to −77.6‰, indicating its biogenic origin. The rates of hydrogenotrophic methanogenesis were low (0.4–5.0 nmol dm −3 day −1 ). Methane oxidation rates varied from 0.4 to 1.2 µmol dm −3 day −1 at the seep stations. Four lineages of anaerobic methanotrophic archaea (ANME) (1, 2a–2b, 2c, and 3) were found in the deeper sediments at the seep stations along with sulfate-reducing Desulfobacteriota . The ANME-2a-2b clade was predominant among ANME. Aerobic ammonium-oxidizing Crenarchaeota (family Nitrosopumilaceae ) predominated in the upper sediments along with heterotrophic Actinobacteriota and Bacteroidota , and mehtanotrophs of the classes Alphaproteobacteria ( Methyloceanibacter ) and Gammaproteobacteria (families Methylophilaceae and Methylomonadaceae ). Members of the genera Sulfurovum and Sulfurimonas occurred in the sediments of the seep stations. Mehtanotrophs of the classes Alphaproteobacteria ( Methyloceanibacter ) and Gammaproteobacteria (families Methylophilaceae and Methylomonadaceae ) occurred in the sediments of all stations. The microbial community composition was similar to that of methane seep sediments from geographically remote areas of the global ocean.

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