16S rRNA gene and 18S rRNA gene diversity in microbial mat communities in meltwater ponds on the McMurdo Ice Shelf, Antarctica

Abstract The undulating ice of the McMurdo Ice Shelf, Southern Victoria Land, supports one largest networks ice-based, multiyear meltwater pond habitats in Antarctica, where microbial mats are abundant and contribute most biomass biodiversity. We used 16S rRNA 18S gene high-throughput sequencing to compare variance community structure within between ponds with different salinities pH. Proteobacteria Cyanobacteria were phyla, composition at OTU level was highly specific for strong sorting along salinity gradient. Our study provides first detailed evaluation eukaryote communities Shelf using gene. They dominated by Ochrophyta, Chlorophyta Ciliophora, consistent previous microscopic analyses, but many OTUs belonging less well-described heterotrophic protists from Antarctic shelves also identified including Amoebozoa, Rhizaria Labyrinthulea. Comparison showed that Eukaryotes had lower richness greater similarity comparison Bacteria Archaea on shelf. While there a weak correlation dissimilarity geographic distance, congruity assemblages ponds, especially , implies habitat filtering shelf ecosystems, due salinity. These findings help understand processes important sustaining biodiversity impact climate change ice-based aquatic Antarctica.