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

The Arctic is experiencing the fastest rate of warming on Earth, leading to the rapid disappearance of sea ice and causing profound impacts on the global climate system, marine environments, and ecosystems. These changes are not merely environmental issues but complex challenges closely linked to climate change, fisheries, Arctic shipping route, resource development, and geopolitics, all of which directly affect global climate stability. This review synthesizes environmental and ecosystem changes in the western Arctic Ocean using multidisciplinary observations from the IBRV ARAON, including long-term field surveys, moorings, sediment traps, eDNA analyses, satellite data, and numerical modeling. The study provides the first evidence that Atlantification has expanded into the East Siberian region, identifying the intrusion of Atlantic-origin water as a key process that can accelerate sea-ice loss. Phytoplankton communities are shifting from diatom-dominated to small flagellate-dominated structures, and both under-ice blooms and subsurface chlorophyll maxima were found to contribute substantially to primary production. Under-ice ecosystems were also shown to play an important role in regulating carbon fluxes. In addition, previously unrecognized biogeochemical anomalies including low-oxygen and highly acidified water masses were identified for the first time in the study. This study demonstrate that increased Atlantic water inflow, enhanced freshwater inputs, and sea-ice decline are jointly intensifying ocean acidification in this study area. Overall, the findings indicate that the western Arctic Ocean is undergoing a rapid transitional phase in which its physical, chemical, and ecological systems are being transformed simultaneously. Future research should focus on advancing long-term Arctic monitoring systems, strengthening international collaborations, and enhancing data interoperability to establish a robust scientific foundation for prediction and management. Furthermore, intensive year-round observations utilizing Korea’s next-generation ice-breaking research vessel will provide critical support for sustainable Arctic Ocean governance and contribute to global climate-change mitigation efforts.