The Sea Journal of the Korean Society of Oceanography ISSN:1226-2978(Print) 2671-8820(Online) 한국해양학회지 바다

The Arctic Ocean is warming faster than any other region on Earth, and the resulting rapid decline in sea ice is causing fundamental changes in ocean circulation and biogeochemical cycles. This review comprehensively examines the rapid transitions occurring in the ocean circulation system of the western Arctic Ocean and the associated changes in nutrient and organic matter cycling, based on data accumulated through Korean icebreaker IBR/V Araon expeditions by the Korea Polar Research Institute and recent international collaborative research. The western Arctic Ocean is currently undergoing two major physical changes: “Atlantification” and “Beaufort Gyre variability.” As Atlantic-origin water extends beyond the Eurasian Basin into the Makarov Basin and East Siberian Sea, it induces weakening of the halocline, shoaling of the nutricline, and phytoplankton blooms. Simultaneously, interannual variability in Beaufort Gyre intensity is driving the spatial redistribution of river water and terrigenous dissolved organic matter. Furthermore, these changes in physical circulation have been confirmed to accelerate hypoxia and ocean acidification in regions such as the Chukchi Plateau. This review suggests that changes in nutrient supply and organic matter cycling in the western Arctic Ocean are driven primarily by Atlantification and Beaufort Gyre variability, highlighting the essential need for quantitative understanding of physical-biogeochemical coupling mechanisms in future Arctic Ocean carbon cycle and ecosystem modeling.