PRJNA471245
Cryoconite holes as vectors for microbial communities of perennially ice-covered lakes in Antarctica
Ultra-oligotrophic Lake Untersee is among the largest and deepest surface lakes of Central Queen Maud Land in East Antarctica. Dammed at its north end by the Anuchin Glacier, it is unsual with respect to other lakes of Antarctica, because the ice-cover dynamics of Lake Untersee are controlled by wind, with ablation—not melt—as the dominating physical process. Because of intense evaporation and sublimation, summer melt does not provide significant amounts of water for recharge, the primary source of water for the lake being subsurface melt from the Aunchin Glacier.There have been a number of studies describing the structure and function of the microbial communities within the water column and benthic environments of Lake Untersee, however thus far there have been no studies that examine the linkages between the lake ecosystem with that of the surrounding soils or the Anuchin Glacier. The Anuchin Glacier, the primary source of water for Lake Untersee may also play an important role as a major contributor of nutrients and biota into the lake ecosystem.Based on microbial 16S rRNA amplicon sequencing, we show the dominating bacterial signatures in Lake Untersee Oasis are affiliated with Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, and Proteobacteria. Aerosol and local soil depositions on the glacier surface result in distinct microbial communities developing in glacier ice and cryoconite holes. Our studies indicate that up to 36% of cryoconite microbial assemblages are also present in Lake Untersee and these cryoconite communities may be a potential source of organisms for the benthic microbial mats in the lake. However, major biotic sources for the lake ecosystem are still unknown, illustrating the possible importance of englacial and subglacial zones.The Anuchin Glacier may be considered as a vector for the bacterial colonization of the perennially ice-covered Lake Untersee and hence shapes the pelagic and benthic ecosystems. Global warming as a result of increasing levels of anthropogenic greenhouse gases may lead to changes of environmental conditions in many habitats resulting in shifts of within the structure and function of microbial communities. These potential impacts require a thorough understanding of the linkages between various dynamic processes such as those observed within the Lake Untersee Oasis.