NASA-supported researchers have discovered a complex organism capable of reproducing at extreme temperatures previously thought entirely unsuitable for eukaryotic life.
Discovery of the Fire Amoeba in California
The organism was located in the thermal waters of Lassen Volcanic National Park in California, United States. According to findings highlighted by NASA on September 23, 2026, the unicellular organism can actively move and forage for food at temperatures as high as 64 degrees Celsius. However, its biological ability to reproduce halts once temperatures exceed 63 degrees Celsius.
This discovery breaks the previous high-temperature record for eukaryotes of 60 degrees Celsius, a mark previously held by certain species of fungi and red algae. The existence of Incendiamoebae cascadensis directly challenges long-held scientific assumptions that eukaryotic cellular membranes and internal organelle structures cannot maintain stability or function at temperatures above 62 degrees Celsius.
Cellular Complexity and Membrane Stability
Unlike prokaryotic organisms such as bacteria and archaea, eukaryotes possess significantly more intricate cellular architectures. Eukaryotic cells feature a defined nucleus that houses genetic material alongside membrane-bound organelles, including mitochondria and the endoplasmic reticulum, which perform vital metabolic functions.
Beryl Rappaport, a graduate student at Syracuse University and the lead author of the study, noted that previous scientific literature regarding eukaryotic thermal limits was constrained by conventional models of membrane stability. Researchers hope this finding encourages broader exploration for high-temperature eukaryotes in other geothermal environments.
Genomic Analysis and Global Implications
To determine how Incendiamoebae cascadensis survives such intense heat, the research team analyzed its genome and evaluated gene activity across various temperature gradients. Investigators identified specific genes that assist in stabilizing DNA, safeguarding essential proteins, and enabling the amoeba to adapt rapidly to environmental fluctuations.
Further genetic comparisons revealed shared genetic material with samples collected from geothermal regions in New Zealand and Yellowstone National Park. These genetic similarities suggest that additional, undiscovered thermophilic amoebas likely inhabit geothermal ecosystems worldwide.
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