Factors affecting the subsurface aragonite undersaturation layer in the Pacific Arctic region.

This study evaluated interannual variation in the subsurface aragonite undersaturation zone (Ω _Ar<1 layer) in the Pacific Arctic Ocean, using data from the 2016-2019 period. The upper boundary (DEP _Ω<1 ^UB ) of the Ω _Ar<1 layer generally formed at a depth where the contribution of corrosive Pacific water was approximately 98 %. The intensity of the Beaufort Gyre associated with freshwater accumulation mainly determined interannual variation in DEP _Ω<1 ^UB , but the direction of its effect was opposite west and east of ~166°W. The lower boundary (DEP _Ω<1 ^LB ) of the Ω _Ar<1 layer was generally found at a depth range where equal contributions of Pacific and Atlantic water were expected. An Atlantic-origin cold saline water intrusion event in 2017 caused by an anomalous atmospheric circulation pattern significantly lifted the DEP _Ω<1 ^LB , thus the thickness of the Ω _Ar<1 layer decreased.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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