Here on Earth, we haven’t found a place too cold or too hot to have life, and our ability to find life just about anywhere is getting truly ridiculous.

In 2016, the Japanese scientific drillship, Chikyu, collected a column of material from the bottom of the sea at the subduction zone of the Nankai Trough. This is a place where the Philippine Sea plate is plunging under the Eurasian plate. Drilling 1.2 kilometers below the seafloor into materials reaching 120˚C, they found a small, active microbial community living where water would boil.

This work is described in a new paper in the journal Nature Communications. Lead author Felix Beulig explains how this is possible: We propose that the organisms are forced to maintain a high metabolic turnover, which approaches the activity of microbes living in surface sediments and in laboratory cultures, to provide the energy required to repair thermal cell damage. 

Study lead Tina Treude adds: The energy required to repair thermal damage to cellular components increases steeply with temperature, and most of this energy is likely necessary to counteract the continuous alteration of amino acids and loss of protein function.

This fast metabolism is radically different from what has been seen before. Collaborator Bo Barker Jørgensen explains: We always found that microbes in the deep biosphere are an extremely sluggish community that slowly nibbles on the last remains of million-year-old, buried organic matter. But the deep biosphere is full of surprises. To find life thriving with high metabolic rates at these high temperatures in the deep seabed nourishes our imagination of how life could evolve or survive in similar environments on planetary bodies beyond Earth.

More Information

New research discovers surprising activity among organisms thriving in extremely deep, hot subseafloor (EurekAlert)

“Rapid metabolism fosters microbial survival in the deep, hot subseafloor biosphere,” F. Beulig et al., 2022 January 25, Nature Communication