Polar cryoconite associated microbiota is dominated by hemispheric specialist genera

Cryoconite holes, supraglacial depressions containing water and microbe-mineral aggregates , are known to be hotspots of microbial diversity on glacial surfaces. Cryoconite holes form in a variety of locations and conditions, which impacts both their structure and the community that inhabits them. Using high-throughput 16S and 18S rRNA gene sequencing, we have investigated the communities of a wide range of cryoconite holes from 15 locations across the Arctic and Antarctic. Through these methods we were able to determine the groups present the family and genus level. Cryoconite holes may be a global phenomenon, but they are inhabited and formed by regionally discrete communities. Our results are consistent with the notion that cryoconite microbiomes are adapted to differing conditions within the cryosphere, which has implications for the response of cryoconite to changing climates of the past and present.