He Zongcai, Cao Ke, Xu Saiya, Zang Kunpeng, Wang Xinyi, Deng Xue, Chen Hong, Wang Mingli, Xing Qinghui, Xu Xuemei
State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian 116023, China.
Eco-Environmental Monitoring and Research Center, Pearl River Valley and South China Sea Ecology and Environment Administration, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou 510610, China.
Mar Pollut Bull. 2025 Oct;219:118234. doi: 10.1016/j.marpolbul.2025.118234. Epub 2025 Jun 3.
The North Yellow Sea (NYS) is considered a typical continental shelf marginal sea, characterized by a complex driving mechanism among land-source runoff, thermocline, and monsoon, that change the transport and exchange of nearshore water masses, indirectly influencing the distribution of methane (CH) in the NYS. During cruises conducted in May, August, and October 2022 and February, June, and September 2023, the surface and bottom dissolved CH concentrations ranged from 4.0 to 26.9 nmol/L and 6.8 to 27.8 nmol/L in the northern of NYS, respectively. The results explain reasons that the response of surface and bottom dissolved CH to changed these parameters (temperature, salinity, DO, chl-a). By integrating the CH concentrations with temperature, salinity, DO%, and depth, the random forest machine-learning models was employed to predict CH concentrations and assess the importance of various variables in the northern NYS. The surface seawater CH were significantly supersaturated, with the saturation (CH%) ranging from 103 % to 1211 %, and the sea-to-air CH fluxes ranging from 0.5 to 190.2 μmol/(m·day), respectively. Overall, the study area had an annual CH emission of 7.8 × 10 mol/yr. Consequently, the northern NYS is identified as a net source of atmospheric CH.
北黄海被认为是典型的大陆架边缘海，其特征是陆源径流、温跃层和季风之间存在复杂的驱动机制，这些机制改变了近岸水体的输送和交换，间接影响了北黄海甲烷（CH）的分布。在2022年5月、8月和10月以及2023年2月、6月和9月进行的航次中，北黄海北部表层和底层溶解CH浓度分别在4.0至26.9 nmol/L和6.8至27.8 nmol/L之间。结果解释了表层和底层溶解CH对这些参数（温度、盐度、溶解氧、叶绿素a）变化的响应原因。通过将CH浓度与温度、盐度、溶解氧百分比和深度进行整合，采用随机森林机器学习模型来预测北黄海北部的CH浓度并评估各种变量的重要性。表层海水CH显著过饱和，饱和度（CH%）范围为103%至1211%，海-气CH通量分别为0.5至190.2 μmol/(m·天)。总体而言，研究区域的年CH排放量为7.8×10 mol/年。因此，北黄海北部被确定为大气CH的净源。
