Microbial communities in ancient permafrost

The prevalence of microbial life in frozen permafrost has been well documented in ancient sediment up to several million years old. However, the long-term survivability, evolution and metabolic activity of buried microbes over geological timespans remain underexplored. We integrated aspartic acid (Asp) racemization assay and metagenomic sequencing to interrogate the microbial activity, phylogenetic diversity and metabolic functions of indigenous, ancient microbial communities across a long chronosequence in the oldest permafrost from northeastern Siberia.