The Pompeii worm’s tail withstands a searing 80潞C (Image: Peter Batson/Image Quest Marine)
Read more: Extreme survival: The toughest life forms on Earth
Meet the bacterium you can boil, the ant that braves the Sahara’s midday sun and a worm that sticks its tail to hot rocks
Heat is a major challenge for life. On land, too much heat means that water evaporates or boils away, and without water nothing can survive.
That is obviously not a problem under the sea. Temperatures can reach 400 掳C in deep-sea hydrothermal vents, where water is heated by the Earth’s interior. The upper temperature limit that organisms can endure becomes the point at which complex molecules, like DNA and proteins, start to break down; the surfeit of energy literally shakes apart their chemical bonds.
The hottest recorded temperature at which life has been able to grow is 121 掳C. This record is held by a microbe called simply Strain 121, which normally lives at temperatures of around 100 掳C in hydrothermal vents; it barely seemed to notice when it was heated to 121 掳C in the lab, in 2003 (). Even at 130 掳C the bacterium was still hanging in there, but it could not replicate until the temperature dropped.
Extreme “thermophiles” like Strain 121 have similar cellular chemistry to you and me. The difference is that their proteins and DNA are more tightly packed, so they can withstand more heat energy before unravelling. However, at temperatures over 100 掳C, essential metabolites such as ATP break down in seconds. So the upper temperature limit on life is set by how quickly a cell can replace these chemicals.…
