Heat‑loving amoeba sets new temperature record for complex organisms

Researchers surveying the geothermal soils of California’s Lassen Volcanic National Park have uncovered a previously unknown amoeba species that flourishes at heat levels once deemed uninhabitable for eukaryotes, setting a fresh record for the maximum temperature tolerance of complex life.

Dubbed Incendiamoeba cascadensis, the microbe was retrieved from scorching, mineral‑laden sediments adjacent to a fumarole on the park’s high‑elevation volcanic landscape. Its identification contributes a vivid new entry to the list of extremophiles—organisms that thrive where most life cannot.

Before this discovery, the hottest environments known to host eukaryotic microbes—like select hot springs and hydrothermal vents—peaked in the mid‑40s Celsius. I. cascadensis, however, showed active metabolism and division at temperatures above 50 °C, a limit that extends the known thermal frontier for nucleated, complex cells.

Scientists point out that the organism’s heat‑tolerance provides new clues about how cellular systems can remain stable under thermal stress. Deciphering these strategies may aid a range of investigations, from forecasting ecosystem responses to rising global temperatures to directing the hunt for extraterrestrial life in similarly scorching settings.

The discovery team, comprising microbiologists from multiple universities, intends to sequence the amoeba’s genome to locate the genetic changes that confer its heat resistance. They also aim to probe its limits in the lab, checking if it can survive even hotter conditions or cope with the rapid temperature swings common in volcanic zones.

The discovery highlights nature’s ability to stretch biological boundaries, while also stressing the need to protect geothermal locales that act as natural research stations. As climate change and human impacts reshape these delicate ecosystems, opportunities to examine such singular organisms may shrink, rendering each finding increasingly crucial for broadening our grasp of life’s adaptability.