Overall ocean health depends critically on dissolved oxygen, which is increasingly impacted by global warming. The Arctic and subarctic regions are experiencing exceptionally rapid warming, known as Arctic amplification, yet its impact on oceanic oxygen remains poorly understood. Here, we show that inflowing Atlantic Water (AW) drives deoxygenation in the upper eastern Arctic Ocean and the intermediate layers of the western Arctic Ocean at rates from -0.41 ± 0.17 to -0.47 ± 0.07 µmol kg^-1 yr^-1, six times the global mean. Amplified Arctic warming is the primary driver, significantly reducing oxygen solubility in the subarctic gateway regions. Rapid subduction and circulation of AW further transmit the deoxygenation signal into Arctic deeper layers, greatly threatening marine ecosystems. Our findings highlight the dominant role of warming Atlantic inflow in shaping the Arctic Ocean oxygen dynamics, indicating that ongoing temperature increases will perpetuate deoxygenation trends and underscoring the need for widespread attention.

Arctic Ocean,Ocean Deoxygenation