This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A new study involving researchers from the Faculty of Science, Charles University, Prague, shows that methane concentration is among the key factors determining the composition of microbial communities at the margin of the Greenland Ice Sheet. The findings, published in Applied and Environmental Microbiology, provide new insights into processes that influence carbon and methane cycling in a rapidly warming Arctic.
Beneath Greenland's vast ice cover lies a surprisingly active microbial world. Microbial communities living in sediments beneath the ice are involved in the production, consumption and transformation of methane (CH₄). New research shows that the amount of methane available may play a major role in determining which microbial communities develop in this environment.
The research team analyzed microorganisms in glacial runoff along an approximately 2,000-kilometer (1,200-mile) transect of the western margin of the Greenland Ice Sheet. Concentrations of dissolved methane varied dramatically between sites, ranging from approximately 0.4 to 50,000 nanomolar, spanning five orders of magnitude. The researchers therefore investigated whether this striking variation was associated with differences in microbial community composition and whether methane could serve as an important source of carbon and energy for microorganisms in these environments.
Using 16S rRNA gene sequencing, the researchers characterized microbial communities in glacial runoff. The communities were dominated by the genera Rhodoferax, Polaromonas, Methylotenera and Crenothrix. The latter represents an important group of microorganisms capable of using methane.
Statistical analyses showed that the concentration of dissolved methane was the strongest identified predictor of microbial community composition along the studied section of the Greenland Ice Sheet. "The results also revealed a link between microorganisms involved in the degradation of complex organic matter and those participating in methane cycling. This suggests that interconnected microbial processes beneath the ice indicate an active carbon-processing network in this environment," says Lia C.
Wentzel, corresponding author of the study from the Faculty of Science at Charles University. The study also revealed a marked difference between sites with low and high methane concentrations. At sites where dissolved methane concentrations exceeded approximately 4.9 nanomolar, microbial communities showed a stronger signal of what ecologists call homogeneous selection.
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