North Pole Plankton
Bolin Centre researchers investigate effect of climate change on under-ice foraminifera
A new study has given Bolin Centre researchers their first detailed look at some of the tiniest – and most important – ocean creatures living beneath the thick ice of the high Arctic Ocean, north of 80°N. These tiny organisms, called planktonic foraminifera, build small shells and are valuable indicators of ocean and climate changes, both today and in the distant past.
Until now, very little was known about which species live in this icy, remote part of the world. But this research fills that gap by collecting samples from 18 locations across the central Arctic, including the Lincoln Sea and nearby fjords. Researchers used special nets to collect these microscopic creatures from different depths, reaching as far as 1000 meters below the surface.
They discovered that nearly all of the living foraminifera in the region belong to a cold-loving species called Neogloboquadrina pachyderma. This species was most common in the top 100 meters of water, likely because it feeds on algae that grow just under the summer sea ice. Only a few individuals of a more southern species, Turborotalita quinqueloba, were found near the edge of the ice, where warmer Atlantic waters flow into the Arctic.
This finding is important because scientists have been expecting a shift in Arctic ecosystems, as warmer Atlantic water moves farther north – a process known as "Atlantification." But so far, it seems that the sea ice is still doing its job as a barrier, keeping most Atlantic species out of the high Arctic.
The team also used digital tools to study the shape and size of the foraminifera shells, hoping to learn more about how these creatures grow and live in such extreme environments.
Overall, the study shows that despite rising temperatures and changing ocean currents, the tiny residents of the central Arctic are still mostly polar specialists. This first snapshot gives scientists a valuable starting point to monitor how life under the ice may change as the region warms and loses more sea ice in the coming years. It also helps improve our understanding of the past, by linking living species to the fossilized shells found in ocean sediments.
The study was published in Biogeosciences, and can be accessed here.
Last updated: August 6, 2025
Source: Bolin Centre for Climate Research