Scientists know that microbial life can survive under some extreme conditions—including, hopefully, harsh Martian weather. But new research suggests that one particular microbe, an algal species found in Arctic ice, isn’t as immobile as it was previously believed. They’re surprisingly active, gliding across—and even within—their frigid stomping grounds.
In a Proceedings of the National Academy of Sciences paper published September 9, researchers explained that ice diatoms—single-celled algae with glassy outer walls—actively dance around in the ice. This feisty activity challenges assumptions that microbes living in extreme environments, or extremophiles, are barely getting by. If anything, these algae evolved to thrive despite the extreme conditions. The remarkable mobility of these microbes also hints at an unexpected role they may play in sustaining Arctic ecology.
“This is not 1980s-movie cryobiology,” said Manu Prakash, the study’s senior author and a bioengineer at Stanford University, in a statement. “The diatoms are as active as we can imagine until temperatures drop all the way down to -15 C [5 degrees Fahrenheit], which is super surprising.”
That temperature is the lowest ever for a eukaryotic cell like the diatom, the researchers claim. Surprisingly, diatoms of the same species from a much warmer environment didn’t demonstrate the same skating behavior as the ice diatoms. This implies that the extreme life of Arctic diatoms birthed an “evolutionary advantage,” they added.
An Arctic exclusive
For the study, the researchers collected ice cores from 12 stations across the Arctic in 2023. They conducted an initial analysis of the cores using on-ship microscopes, creating a comprehensive image of the tiny society inside the ice.
To get a clearer image of how and why these diatoms were skating, the team sought to replicate the conditions of the ice core inside the lab. They prepared a Petri dish with thin layers of frozen freshwater and very cold saltwater. The team even donated strands of their hair to mimic the microfluidic channels in Arctic ice, which expels salt from the frozen apparatus.
As they expected, the diatoms happily glided through the Petri dish, using the hair strands as “highways” during their routines. Further analysis allowed the researchers to track and pinpoint how the microbes accomplished their icy trick.
The researchers developed and used special microscopes and experimental environments to track how the diatoms move through ice. Credit: Prakash Lab/Stanford University
“There’s a polymer, kind of like snail mucus, that they secrete that adheres to the surface, like a rope with an anchor,” explained Qing Zhang, study lead author and a postdoctoral student at Stanford, in the same release. “And then they pull on that ‘rope,’ and that gives them the force to move forward.”
Small body, huge presence
If we’re talking numbers, algae may be among the most abundant living organisms in the Arctic. To put that into perspective, Arctic waters appear “absolute pitch green” in drone footage purely because of algae, explained Prakash.
The researchers have yet to identify the significance of the diatoms’ gliding behavior. However, knowing that they’re far more active than we believed could mean that the tiny skaters unknowingly contribute to how resources are cycled in the Arctic.
“In some sense, it makes you realize this is not just a tiny little thing; this is a significant portion of the food chain and controls what’s happening under ice,” Prakash added.
That’s a significant departure from what we often think of them as—a major food source for other, bigger creatures. But if true, it would help scientists gather new insights into the hard-to-probe environment of the Arctic, especially as climate change threatens its very existence. The timing of this result shows that, to understand what’s beyond Earth, we first need to protect and safely observe what’s already here.
