Microbial Life Under Pressure:  who’s there and how do they adapt?

A major portion of microbial life on Earth is present in low-temperature/deep-sea environments, and yet much remains to be learned of their diversity, adaptations and activities.  Studies of these microbes in situ and ex situ is providing fundamental and biotechnological insights, and will be critical to many possible ocean-based decarbonization processes.  In this presentation I will first discuss what we have learned about proteomes and cell envelopes of piezophilic (high pressure-adapted) isolates.  Then I will transition to investigations of deep-sea microbial activities using pressure-retaining seawater sampling to collect microbes with minimal temperature/pressure alteration, followed by the sorting and identification of cells active under in situ deep-sea conditions.  One aspect of this work is the indication that certain microbial groups (e.g., members of the Thaumarchaeota) are highly sensitive to decompression/incubation effects, reducing their perceived significance when collected using standard methods.