Anthropogenic Forcing and Upwelling Accelerate Aragonite Undersaturation in the Prydz Bay, East Antarctica

作者：Shuang Zhang, Yingxu Wu, Wanqin Zhong, Liqi Chen, Di Qi · 发表于：Journal of Geophysical Research Oceans · 年份：2025 · DOI：10.1029/2025jc023039 · 研究领域：Ocean Acidification Effects and Responses、Marine and coastal ecosystems、Methane Hydrates and Related Phenomena

Abstract The Southern Ocean is one of the rapidly acidifying regions globally, yet direct observational constraints on its carbonate chemistry remain scarce. Here, we combine shipboard measurements of pH and aragonite saturation state (Ω arag ) from the summer 2015 Chinese National Antarctic Research Expedition with reconstructed wintertime conditions to characterize acidification in Prydz Bay. We report the first observation‐based occurrence of surface aragonite undersaturation (Ω arag < 1.0) in the northern basin—emerging nearly two decades earlier than model projections. Surface Ω arag undersaturation is primarily driven by accelerated uptake of anthropogenic CO 2 and shoaling of the aragonite saturation horizon, fueled by persistent upwelling of CO 2 ‐rich Circumpolar Deep Water. In the ocean interior, organic matter remineralization, CaCO 3 dissolution, and continued anthropogenic CO 2 intrusion further lower pH and Ω arag . Our results demonstrate that Prydz Bay is at the forefront of Southern Ocean acidification, highlighting the urgent need to incorporate both anthropogenic and natural biogeochemical feedbacks into high‐resolution models to better predict future ecological impacts.