Fig. 3

Distinct microbial profiles between PS and S3 ice cores. a Microbial profiles of the 26 most abundant genera in PS and S3 ice core samples. Profiles are illustrated as a percent of the total 16S rRNA gene amplicon sequences. The key indicates genera, preceded by family, or order in cases where family is not assigned. Genera labeled “Other” represent sequences with unknown genus-level taxonomy, i.e., distinct from taxonomically assigned genera in the reference database. The 26 most abundant genera, defined as those comprising at least 1.0% of the sequences in at least one ice sample, collectively represented >95.1% of each community. The total relative abundance of these genera was normalized to 100%. b PCoA showing sample clustering based on microbial communities at OTU (~species, 97% identity) level. Samples from the same ice core are marked with the same color. Sample names are indicated next to each symbol. PCoA was performed on the weighted UniFrac metric, which accounts for the relative abundance and inferred relatedness of the lineages present