Structure and diversity of archaea and methanogenic archaea in sediments of selected freshwater lakes, Antarctic Peninsula

Abstract

This research is the first study focusing to explore the diversity of Archaea and methanogens in sediments of 19 selected lakes nearby the Czech polar station on James Ross Island (JRI), Antarctica. The 16S rRNA gene sequencing provided a general view of a diversity of archaeal members and the mcrA gene sequencing has offered deeper insight into the taxonomical diversity of methanogens. Archaea rarely exceeded 1% of the total prokaryotic community. Genera Methanothrix and Methanosarcina were found as the predominating methanogenic members in the lake samples. For the first time in Antarctica, sequences of representatives belonging to Methanothermobacter sp. and Methanomassiliicoccales, and a high proportion of sequences belonging to Methanoperedens-like archaea, methanotrophs that couples anaerobic methane oxidation to denitrification, were recorded. The presence of the genus Methanobacterium has been also captured for the first time to a such large extent. Individual lakes from one area shared much higher similarity in their methanogenic diversity with the lakes from another area rather than with the lakes within the same area, suggesting that a lake location will be not the main factor influencing the diversity of the methanogens. Our research unambiguously provides evidence that the lakes of the JRI and surrounding islands are a potential source of new archaeal species.