Ice Diatoms Break Ice on Motion in the Cold
Hidden within the Arctic’s frozen seas are microscopic organisms that do more than survive. New research reveals that ice diatoms can actively glide through ice, seeking out better light and nutrient sources. In a combination of in situ fieldwork and laboratory experiments, these single-celled algae demonstrated gliding speeds about ten times faster than their temperate counterparts, continuing to move at temperatures as low as −15°C—the coldest temperature at which a eukaryotic cell has shown motility.
How Ice Diatoms Move in Subzero Worlds
Diatoms are microscopic, photosynthesizing algae that contribute a substantial portion of the planet’s oxygen. Though scientists have known since the 1960s that diatoms inhabit and traverse the ice matrix, the mechanisms of their movement have remained elusive. The research team, led by Manu Prakash of Stanford University, used a temperature-controlled microscope capable of subzero conditions and examined diatoms extracted from young sea ice collected during a 45-day expedition in the Chukchi Sea aboard an icebreaking research vessel.
According to Prakash, “Ice is an incredible porous architecture of highways.” Light enters from the ice surface while nutrients arrive from below. In this gradient, motility enables a diatom to reposition itself toward the optimal microenvironment. The team observed ice diatoms gliding on ice surfaces and through ice channels, maintaining activity even at −15°C—far below the temperatures at which other organisms have demonstrated motion.
Why Motility Matters in the Ice
Researchers compared ice diatoms with temperate diatoms under identical conditions on both ice and glass. The ice specialists moved roughly ten times faster than their temperate counterparts. When cooled on icy surfaces, temperate diatoms either slowed dramatically or drifted passively. These findings suggest that ice diatoms not only tolerate extreme cold but actively seek out favorable light and nutrient microhabitats, effectively enhancing their survival in an otherwise harsh landscape.
Implications for Polar Ecosystems and Climate Change
The Arctic is warming at a pace faster than many other regions, threatening both visible wildlife and microscopic communities. Diatoms form the backbone of many aquatic ecosystems, contributing to oxygen production and supporting food webs. As sea ice extent declines, the ability of ice diatoms to navigate their icy environment could be altered, with ripple effects across polar ecosystems.
Prakash notes that this discovery prompts a broader view of Arctic environments, emphasizing the micro-scale interactions that sustain macro-scale ecosystems. Ongoing research aims to determine how chemical conditions such as salinity influence diatom gliding and how these organisms shape the contours of the ice they inhabit.
Looking Ahead
Beyond understanding basic biology, scientists hope to integrate these insights into predictions about microbial responses to climate change. If ice diatoms must adapt their motility as sea ice retreats, the consequences could extend to oxygen production, nutrient cycling, and overall ecosystem resilience. As Julia Diaz of the Scripps Institution of Oceanography observed, sea ice is not a passive barrier but a vibrant habitat whose biodiversity and innovations matter to global climate systems.
Overall, the discovery of rapid, cold-loving motility in ice diatoms highlights the remarkable strategies life employs to persist in the most extreme environments and underscores the urgency of protecting polar ecosystems as they face rapid climatic shifts.
