STANFORD, CA — A new study from Stanford University has overturned the assumption that diatoms tiny, single-celled algae encased in glass-like shells found in Arctic ice cores are dormant. Researchers found that these microscopic organisms are actively moving, or “skating,” through the frozen environment, establishing a new record for movement in a complex eukaryotic cell at extremely low temperatures.
The research, published in the Proceedings of the National Academy of Sciences, found that the diatoms remain active and motile until temperatures drop all the way down to -15 °C {5 °F}. This figure marks the lowest temperature ever documented for movement in a eukaryotic cell.
Mucus and Molecular Motors Power Icy Movement
The diatoms were collected during a 45-day Arctic research expedition in the Chukchi Sea. Back in the lab, researchers recreated the diatoms’ environment a thin layer of frozen freshwater containing microfluidic channels and observed their motion using specialized sub-zero microscopes.
The study revealed that the diatoms move not by wiggling or using appendages, but by gliding. This motion is powered by:
• Mucus Secretion: The diatoms secrete a polymer, described as being “like snail mucus,” that adheres to the surface, acting as a “rope with an anchor.”
• Molecular Machinery: They then pull on this “rope” using the actin and myosin biological system, the same machinery that drives human muscle movement.
The fact that this complex machinery remains functional in subzero conditions is now a major question for further research. Interestingly, when compared to their temperate relatives, the polar diatoms were found to move much faster, suggesting an evolutionary advantage.
Urgency in a Disappearing Arctic
Senior author Manu Prakash stressed the urgency of this discovery, as the melting Arctic threatens to erase entire branches of the tree of life. The active diatoms form a “hidden green world” beneath the ice, making up a significant portion of the Arctic food chain, potentially nourishing everything from fish to polar bears.
The new knowledge about the diatoms’ activity raises critical questions about their role in the food web and their adaptation to the rapidly changing polar environment. Prakash noted the profound loss of knowledge that occurs when ecosystems disappear, a concern amplified by projected severe budget cuts to polar research funding.