Wei Yawen, Xu Saiya, Xu Xuemei, Wang Xinyi, Deng Xue, Yao Zhentong, Yang Wei, Zang Kunpeng, Chen Hong, Han Jianbo
State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Linghe Street 42, Shahekou District, Dalian, 116023, Liaoning Province, China.
College of Ocean Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
Mar Environ Res. 2025 Oct;211:107459. doi: 10.1016/j.marenvres.2025.107459. Epub 2025 Aug 18.
This study investigated the carbonate dynamics in the northern coastal zone of the Northern Yellow Sea adjacent to the Yalu River estuary during two distinct hydrological periods in 2024. During the dry season, seawater dissolved inorganic carbon (DIC) ranged narrowly from 1862 μmol kg to 2141 μmol kg, while pH ranged from 7.70 to 8.02. In contrast, during the flood season, seawater DIC decreased to 1332-2111 μmol kg, with pH exhibiting greater variability from 7.63 to 8.48. End-member mixing modeling revealed that physical mixing was the dominant controlling factor during the dry season. However, during the flood season, the surface water exhibited a DIC depletion of up to -316 μmol kg and an increase in pH by 0.54 relative to conservative mixing. Conversely, the bottom water showed an inverse pattern, with DIC accumulation reaching up to 210 μmol kg accompanied by a decrease in pH of 0.17. Combined with stable carbon isotopic analysis, both carbon dioxide outgassing and biological activities demonstrated considerable influence despite strengthened physical mixing due to intensified river input. Furthermore, the critical role of acid-base buffering capacity in regulating pH was presented. Seawater with higher buffering capacity during the flood season showed improved ability to maintain pH stability. Primary production may enhance seawater buffering capacity, while organic matter degradation could weaken it. These mechanistic insights provide a foundation for developing targeted strategies aimed at enhancing buffering capacity in anthropogenically impacted coastal ecosystems to promote CO sinking and build resilience to ocean acidification.
本研究调查了2024年两个不同水文时期鸭绿江口附近北黄海北部海岸带的碳酸盐动力学。在旱季，海水溶解无机碳（DIC）范围较窄，为1862 μmol/kg至2141 μmol/kg，而pH值范围为7.70至8.02。相比之下，在汛期，海水DIC降至1332 - 2111 μmol/kg，pH值变化更大，为7.63至8.48。端元混合模型表明，旱季物理混合是主要控制因素。然而，在汛期，表层水相对于保守混合表现出高达-316 μmol/kg的DIC亏损和pH值升高0.54。相反，底层水呈现相反模式，DIC积累高达210 μmol/kg，同时pH值下降0.17。结合稳定碳同位素分析，尽管由于河流输入增加导致物理混合增强，但二氧化碳脱气和生物活动都显示出相当大的影响。此外，还阐述了酸碱缓冲能力在调节pH值方面的关键作用。汛期缓冲能力较高的海水表现出更好的维持pH值稳定性的能力。初级生产可能增强海水缓冲能力，而有机物降解可能削弱它。这些机制性见解为制定有针对性的策略奠定了基础，这些策略旨在增强受人为影响的沿海生态系统的缓冲能力，以促进碳下沉并增强对海洋酸化的抵御能力。
