Discriminative biogeochemical signatures of methanotrophs in different chemosynthetic habitats at an active mud volcano in the Canadian Beaufort Sea
Lee, D.-H.; Lee, Y.M.; Kim, J.-H.; Jin, Y.K.; Paull, C.; Niemann, H.; Kim, J.-H.; Shin, K.-H. (2019). Discriminative biogeochemical signatures of methanotrophs in different chemosynthetic habitats at an active mud volcano in the Canadian Beaufort Sea. NPG Scientific Reports 9: 17592. https://dx.doi.org/10.1038/s41598-019-53950-4
In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322; e-ISSN 2045-2322, more
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| Authors | | Top |
- Lee, D.-H.
- Lee, Y.M.
- Kim, J.-H.
- Jin, Y.K.
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- Paull, C.
- Niemann, H., more
- Kim, J.-H.
- Shin, K.-H.
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| Abstract |
Several mud volcanoes are active in the Canadian Beaufort Sea. In this study, we investigated vertical variations in methanotrophic communities in sediments of the mud volcano MV420 (420 m water depth) by analyzing geochemical properties, microbial lipids, and nucleic acid signatures. Three push cores were collected with a remotely operated vehicle from visually discriminative habitats that were devoid of megafauna and/microbial mats (DM) to the naked eye, covered with bacterial mats (BM), or colonized by siboglinid tubeworms (ST). All MV420 sites showed the presence of aerobic methane oxidation (MOx)- and anaerobic methane oxidation (AOM)-related lipid biomarkers (4α-methyl sterols and sn-2-hydroxyarchaeol, respectively), which were distinctly different in comparison with a reference site at which these compounds were not detected. Lipid biomarker results were in close agreement with 16S rRNA analyses, which revealed the presence of MOx-related bacteria (Methylococcales) and AOM-related archaea (ANME-2 and ANME-3) at the MV420 sites. 4α-methyl sterols derived from Methylococcales predominated in the surface layer at the BM site, which showed a moderate methane flux (0.04 mmol cm−2 y−1), while their occurrence was limited at the DM (0.06 mmol cm−2 y−1) and ST (0.01 mmol cm−2 y−1) sites. On the other hand, 13C-depleted sn-2-hydroxyarchaeol potentially derived from ANME-2 and/or ANME-3 was abundant in down-core sediments at the ST site. Our study indicates that a niche diversification within this mud volcano system has shaped distinct methanotrophic communities due to availability of electron acceptors in association with varying degrees of methane flux and bioirrigation activity. |
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