Govind Tekale
Scientists have discovered that tiny algae inside Arctic ice aren’t just surviving – they’re actively moving at the coldest temperatures ever recorded for living cells. These single-celled algae, called diatoms, can glide through ice channels at temperatures as low as -15°C (5°F), shattering previous beliefs about life’s limits in extreme environments.
According to Manu Prakash, bioengineering associate professor at Stanford and the study’s senior author, these diatoms remain surprisingly active until the temperature reaches -15°C. He expressed amazement at this finding in the research published in the Proceedings of the National Academy of Sciences.
Scientists from Stanford’s Prakash and Arrigo laboratories made this discovery while on a 45-day journey to the Chukchi Sea in the Arctic. During summer 2023, they extracted ice samples from a dozen sites using the National Science Foundation’s research ship Sikuliaq, which is run by the University of Alaska Fairbanks.
Using specialized microscopes developed by the Prakash Lab, researchers observed diatoms moving inside ice. Back at their lab, they recreated Arctic conditions in petri dishes with layers of frozen freshwater over very cold saltwater. Even in these artificial environments, the diatoms continued to move.
Lead author Qing Zhang, a Stanford postdoctoral scholar, explained how these organisms move: “There’s a polymer, kind of like snail mucus, that they secrete that adheres to the surface, like a rope with an anchor. And then they pull on that ‘rope’ and that gives them the force to move forward.”
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This movement depends on actin and myosin – the same molecular motors that power human muscle movements. The fact that this machinery works at temperatures well below freezing opens new questions about how cellular components adapt to extreme cold.
When compared to similar diatoms from warmer regions, the Arctic species moved faster, suggesting evolutionary adaptations that give them an advantage in cold environments.
The discovery carries important implications for Arctic ecosystems. Drone footage taken under the ice revealed that the Arctic underside is “absolute pitch green because of the presence of algae,” according to Prakash. These actively moving diatoms may transport nutrients through the polar food web, potentially nourishing everything from microorganisms to fish and, indirectly, polar bears.
Researchers are now exploring whether the mucus trails left by diatoms might even help form new ice crystals, similar to how pearls grow around sand grains.
The team expressed urgency about continuing this research, noting concerns about climate change impacts on the Arctic and potential funding cuts to polar science. “Many of my colleagues are telling me, in the next 25 to 30 years, there will be no Arctic,” Prakash said, adding that projected budget cuts could reduce National Science Foundation polar research funding by 70 percent.
As we learn more about these remarkable organisms and their role in one of Earth’s most extreme environments, scientists emphasize the importance of preserving both the Arctic itself and the research infrastructure needed to study it.
