The Korea Polar Research Institute (KOPRI) said on the 23rd that it announced research findings showing that the early collapse of Arctic sea ice due to climate change affects the biological pump. The findings were published in March in the international journal Limnology and Oceanography.
The biological pump refers to the process by which organic matter in the ocean sinks to the deep sea, sequestering carbon for long periods. Algae called "sea-ice microalgae," photosynthetic microalgae that mainly inhabit the interior and bottom of sea ice, drop into the ocean when the ice melts, become food for zooplankton, fish, and benthic organisms, and contribute to carbon sequestration via the biological pump. Sea-ice microalgae account for up to 60% of primary producers across the Arctic Ocean, making them substantial in scale.
KOPRI researchers analyzed long-term data collected over six years since 2017 in the East Siberian and Chukchi seas of the Arctic by the icebreaking research vessel Araon. Using a sediment trap attached to a Korea-designed ocean mooring system developed in-house, the team was able to observe the long-term sinking of sea-ice microalgae.
According to the study, as climate change accelerates the collapse of Arctic sea ice, the timing of the sinking—when microalgae that had inhabited the ice detach and sink to the deep sea—has moved earlier, and shifts in the supply of nutrients that serve as the algae's food have altered both production and the persistence of sinking. When nutrients were sufficient, production and sinking continued for longer, but when they were scarce, the amount of sinking tended to decrease.
Yang Eun-jin, principal researcher at the Ocean and Atmospheric Research Division, said, "The decline of Arctic Ocean sea ice due to climate change goes beyond the simple disappearance of ice and can trigger structural changes across the Arctic Ocean food web and carbon cycle," adding, "Changes in sinking amounts driven by early sinking from sea-ice collapse and reduced nutrient supply can ultimately decrease the amount of carbon sequestered in the deep sea, acting as a factor that accelerates global warming."
Shin Hyeong-cheol, president of the Korea Polar Research Institute (KOPRI), said, "The Arctic Ocean has recently drawn attention as a shipping route and a resource deposit, but it is also a key arena that determines the stability of the global climate. Long-term, precise observation of changes in the Arctic ecosystem will be the starting point for responding to climate change and protecting our future."
References
Limnology and Oceanography(2025), DOI: https://doi.org/10.1002/lno.70032