For all its beauty, Yellowstone National Park is a terrifying place. If it erupted tomorrow, most of America would be drowned in ash, and they wouldn’t see sunlight for weeks. Add extreme pressures, no nutrients and oxygen depletion to the searing heat in volcanic pools and you can understand why we used to think life here was impossible.
However, those amazing dashes of red, green and yellows sweeping across the volcanic pools are not from the rocks but from microbial life which aren’t just tolerating the scorching heat, but need it to survive.
Apart from being a liiitle bit painful, if I jumped in the pool and tried to survive, my cell membranes would crumble, my enzymes and proteins would melt and my DNA simply unravel and fall apart. How is it then, that at 115°C we still find archaea (single celled organisms which are as different from bacteria as we are)?
To survive and grow, these archaea have ultra strong membranes to stop the cell from melting. Weirdly, they then pump salt into their cells, acting as a clamp to hold the protein and DNA structures together, so they don’t fragment. For food the ingenious and complicatedly named Sulfolobus acidocaldarius actually sticks and clings onto sulphur crystals and uses the hydrogen sulphide to gather energy.
Nothing so far has been found above 120°C as it is thought any large molecules will simply fall apart. But, we have been wrong before.
As an aside to why you should care, the first ever life, which has given rise to you, me and everything living almost definitely lived in a deep sea volcano. Furthermore, the enzyme used to replicate DNA and sequence entire genomes was isolated from a bacteria living in a volcano.
If you are interested, I will be writing about various extreme life in the near future, including life in space, other planets, inside ice, rocks and salt and will be asking whether it is possible for an organism to live for 250 million years.