This work presents a comprehensive spatial distribution of aragonite saturation state (Ωara) during fall 2022 across the entire shelf of the East China Sea (ECS), a marginal sea of the North Pacific. Our observations revealed pronounced spatial heterogeneity in Ωara. Specifically, surface Ωara was higher in the southeastern ECS in (3.22−3.41), which is influenced by the Taiwan Warm Current and the Kuroshio, than the northern ECS (2.23−2.60), which is affected by the Yellow Sea and the Changjiang River. The lowest Ωara values (1.73−2.20) occurred beneath the mixed layer on the southeastern ECS shelf. Correlation analyses and a one-dimensional diagnostic model identified biological activity and temperature as primary controls on the spatial variability of Ωara. For example, on the southeastern ECS shelf, within the mixed layer, both biological activities and temperature increased Ωara, accounting for ~45% and ~33% of the total absolute contribution of each process. While below the mixed layer, these two processes decreased Ωara, accounting for approximately -38% and -24% of the total absolute contribution. Additionally, water mass mixing substantially influenced Ωara within interaction zones, such as in the intrusion areas of the Yellow Sea and Changjiang River waters. Projections indicate that under future elevated atmospheric carbon dioxide conditions (RCP6.0 and RCP8.5), sea surface Ωara will continue to decline, but the magnitude of decline will be smaller in the northern ECS than in the southeastern ECS, reflecting the carbonate system’s intrinsic buffering effect.
Qiao H., Wang H., Xin M., Wang P., Wei Q., Ran X. & Xue L., 2026. Aragonite saturation state in the East China Sea during fall 2022: roles of temperature, biology, and mixing. Acta Oceanologica Sinica 45(6): 1–14. Article.
