60°C: until less than a month ago, this was the temperature above which it was thought that complex life could not exist. But records are made to be broken: in the geothermal springs of Lassen Volcanic National Park, California, an amoeba was discovered that lives and thrives well above 60°C. Baptized Let’s set fire to Eba cascadensiswas described in a study published in Cell.
The fiery amoeba
When looking for organisms capable of living in extreme temperatures, volcanic areas are always the first choice. In the Californian national park where the Syracuse University team conducted the study, for example, there are several geothermal springs in which water flows at temperatures between 47 and 64 °C. This is where the researchers collected, between 2023 and 2025, several organisms living in extreme heat; among these, the fire amoeba immediately stood out.
Taken into the laboratory, this single-celled organism continued to grow smoothly up to 57°C, the previous record for an amoeba. The researchers then raised the temperature, exceeding the limit of 60 °C: having reached 63, the amoeba began to divide by mitosis, demonstrating that it was not only withstanding the extreme heat, but was actually thriving.
It is a record for a eukaryotic organism – while if we extend to prokaryotes we must mention the archaea Methanopyrus kandleriwhich lives near oceanic hydrothermal winds at 122°C.
Yes, but how does he do it?
As for the “how”, the fire amoeba is able to change shape to cope with high temperatures: when the mercury column exceeds 63 °C, it forms a protective layer around the nucleus, which allows it to survive up to 70 °C (the highest temperature at which it has been tested).
The amoeba genome, among other things, contains some genes normally associated with protein and DNA repair: it is possible that they serve as further protection against damage from extreme heat.
The real biochemical secret of the fire amoeba, however, could be the presence of positively charged amino acids on its surface, a common feature also in bacteria and archaea that live at high temperatures: according to the authors, these molecules help keep proteins stable, which otherwise, exposed to extreme heat, could disintegrate.
