A single-celled organism squirming about in the searing waters of California’s Lassen Volcanic National Park has just set a record for heat tolerance.
The newly named Incendiamoeba cascadensis – meaning “fire amoeba from the Cascades”, as described in a preprint on bioRxiv – grows and divides at temperatures up to 63 degrees Celsius (145 Fahrenheit), the highest known temperature for a eukaryotic organism.
Moreover, it doesn’t start growing until temperatures reach at least 42 degrees Celsius. This makes it an obligate thermophile – a creature that requires conditions far hotter then most eukaryotic organisms can endure.
Related: This Is The First Animal Ever Found That Doesn’t Need Oxygen to Survive
“Our findings,” writes a team led by biologists H.Beryl Rappaport and Angela Oliverio of Syracuse University in New York, “challenge the current paradigm of temperature constraints on eukaryotic cells and reshape our understanding of where and how eukaryotic life can persist.”
Life on Earth tends to cluster around specific conditions, with the optimum temperature for most organisms, including humans, hovering around 20 degrees Celsius.
Some organisms, though, have adapted to conditions far harsher than the norm, from scorching volcanic vents under crushing ocean pressures, to acidic geothermal pools, to the driest desert on Earth.
I. cascadensis in its elongated vermiform state for faster motion (B, E) and amoeboid state for feeding and exploring (C, D). (Rappaport et al., bioRxiv, 2025)
The overwhelming majority of these extremophile organisms are prokaryotes, a group that includes bacteria and archaea.These are single-celled organisms, too, but they are dramatically different from eukaryotic organisms.
Prokaryotes are simpler, more primitive; they don’t pack genetic material into nuclei or organelles.
Heat-Loving Microbe Discovered in Yellowstone and New zealand Could Redefine Limits of Life
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A newly discovered microbe, Incendiamoeba cascadensis, thrives in scorching temperatures previously thought uninhabitable for complex life, challenging our understanding of eukaryotic cell limits and offering insights into the potential for life on other planets. Researchers found evidence of this heat-loving organism in hot springs across Yellowstone national Park and the Taupō Volcanic Zone in New Zealand.The findings, currently available as a preprint, suggest life may be far more adaptable than previously believed.
Discovery and Characteristics of Incendiamoeba cascadensis
Incendiamoeba cascadensis is a single-celled eukaryotic organism – meaning its cells have a nucleus enclosed within membranes – that flourishes in extremely hot environments. Specifically,it proliferates at temperatures exceeding the previously established maximum tolerance for any known eukaryotic organism. While the exact upper temperature limit is still under investigation, its survival in these conditions is remarkable.
The discovery wasn’t based on isolating and culturing the organism, but rather on identifying unique DNA sequences in environmental samples. Researchers analyzed environmental DNA (eDNA) collected from hot springs in both Yellowstone and New Zealand, finding nearly identical genetic signatures in both locations. This suggests a widespread, though possibly sparse, distribution of I.cascadensis or closely related species. The presence of chaperone proteins,which help other proteins maintain their structure under stress,further supports the microbe’s adaptation to extreme heat.
Implications for Understanding Life’s Limits
this discovery has significant implications for the field of biology. Eukaryotic cells are more complex than prokaryotic cells (like bacteria and archaea), and were thought to be more vulnerable to high temperatures. I.cascadensis demonstrates that eukaryotic life can withstand conditions previously considered prohibitive.
As the researchers note in their preprint publication on bioRxiv, “Incendiamoeba cascadensis proliferates at temperatures beyond what was thought possible for any eukaryotic organism. this discovery raises new questions about the true maximum temperature a eukaryotic cell can endure.”
Understanding how I. cascadensis survives at such high temperatures could reveal novel mechanisms of cellular adaptation and provide insights into the evolutionary constraints on life.This knowledge could also inform the progress of new technologies, such as heat-resistant enzymes for industrial applications.
Astrobiological Importance: Searching for Life Beyond Earth
Perhaps the most exciting aspect of this discovery is its relevance to astrobiology – the study of the origin, evolution, distribution, and future of life in the universe.Many potentially habitable environments on other planets and moons, such as Europa (a moon of Jupiter) and Enceladus (a moon of Saturn), are thought to harbor subsurface oceans with hydrothermal activity.
The existence of I.cascadensis expands the range of conditions under which life might be possible.If life can thrive in the extreme heat of Yellowstone and Taupō, it raises the possibility that similar organisms could exist in analogous environments elsewhere in our solar system and beyond.
The researchers emphasize the broader implications: “these results have profound implications for our understanding of the evolutionary constraints on eukaryotic cells and the set of abiotic parameters that inform the search for life elsewhere in the universe.”
Key Takeaways:
* A new microbe,Incendiamoeba cascadensis,has been discovered thriving in extremely hot springs in Yellowstone and New Zealand.
* This microbe is a eukaryote, challenging previous assumptions about the temperature limits of complex life.
* The discovery expands the range of conditions considered habitable, with significant implications for the search for life on other planets.
* The research was initially published as a preprint on bioRxiv, awaiting peer review.
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