A newly identified amoeba can continue multiplying at temperatures as high as 63°C, setting a new record for heat tolerance among eukaryotic microorganisms. The species, named Incendiamoeba cascadensis, was described in a study published in Cell on October 1.
Researchers isolated the amoeba from samples taken in a stream fed by hot springs in California’s Lassen Volcanic National Park. Water temperatures there range from 49°C to 65°C. The organism cannot grow below 40°C and grows best between 55°C and 57°C.
Unlike organisms that only survive brief exposure to high temperatures, I. cascadensis can multiply at up to 63°C. It can also actively pursue the bacteria it feeds on at temperatures as high as 64°C. Above that point, it forms a dormant cyst, a state that allows it to survive temperatures up to 70°C.
Before this discovery, the highest recorded temperatures for eukaryotic microorganisms—organisms whose cells have a nucleus—reached 60°C, a limit observed in some fungi and algae. Some bacteria and archaea can withstand much higher temperatures, but they belong to different domains of life.
Sources: Le Monde Sciences.