Lee Inhee, Hahm Doshik, Cho Hyung-Mi, Rho TaeKeun, Kim Guebuem, Lee Tongsup
Department of Oceanography, Pusan National University, Busan, 46241, South Korea.
Department of Oceanography, Pusan National University, Busan, 46241, South Korea; Marine Research Institute, Pusan National University, Busan, 46241, South Korea.
Mar Environ Res. 2025 Aug 29;212:107458. doi: 10.1016/j.marenvres.2025.107458.
The Yellow Sea (YS) and the East China Sea (ECS), which comprise continental shelves with depths of 200 m or less, are recognized as some of the most productive coastal areas globally. Although this high productivity can contribute to carbon sequestration, the spatiotemporal variability of the biological pump remains unclear. To investigate this variability, net community production (NCP) in August 2020 was estimated based on high-resolution O/Ar measurements. The study area was divided into Yellow Sea Water (YSW) in the southern YS, Changjiang Diluted Water (CDW) with salinity < 30, and Cheju Warm Current Water (CWCW) in the northern ECS. In YSW and CDW, the seasonal variation in NCP during the warm period was evaluated in conjunction with the results from the previous spring, revealing contrasting trends between YSW and CDW. In YSW, the summer NCP of 25 ± 6 mmol O m d was lower than the spring NCP of 49 ± 19 mmol O m d, primarily due to nutrient depletion in the mixed layer caused by stronger stratification. Conversely, in CDW, the summer NCP of 67 ± 28 mmol O m d exceeded the spring NCP of 26 ± 13 mmol O m d, mainly due to nutrient inputs from Changjiang River discharge. Meanwhile in CWCW, which is not influenced by river, the summer NCP was 32 ± 21 mmol O m d, showing little seasonal variation between spring and summer. To assess the efficiency of the biological pump, we measured the net community production (NCP) and gross primary production (GPP) using O in vitro method for the first time in this region. The (NCP/GPP) ratios ranged from 0.20 to 0.27 in YSW and 0.21 to 0.26 in CWCW, indicating similar efficiencies. These efficiencies were approximately twice those of the open ocean. The (NCP/GPP) was 0.35 in CDW, likely due to increased productivity driven by the Changjiang River during summer. This efficiency not only approaches the global upper limit but is also comparable to regions affected by episodic events such as upwelling and spring blooms, highlighting the potential of CDW as a significant carbon sink. This study provides valuable insights into the role of the continental shelves as a carbon sink and helps reduce uncertainties in shelf carbon uptake. Furthermore, to enhance the spatial applicability of high-resolution observations, underway NCP data were integrated with satellite-derived oceanographic variables to develop a Random Forest model. This approach underscores the potential of utilizing observational datasets to estimate large-scale NCP, reinforcing the critical role of continental shelves in global carbon cycling.
黄海（YS）和东海（ECS）由深度在200米及以下的大陆架组成，被认为是全球生产力最高的一些沿海地区。尽管这种高生产力有助于碳固存，但生物泵的时空变异性仍不清楚。为了研究这种变异性，基于高分辨率的O/Ar测量估算了2020年8月的净群落生产力（NCP）。研究区域分为南黄海的黄海海水（YSW）、盐度<30的长江冲淡水（CDW）以及东海北部的济州暖流（CWCW）。在YSW和CDW中，结合前一个春季的结果评估了暖期NCP的季节变化，揭示了YSW和CDW之间的对比趋势。在YSW中，夏季NCP为25±6 mmol O m² d，低于春季的49±19 mmol O m² d，主要是由于更强的层化导致混合层中的营养物质耗尽。相反，在CDW中，夏季NCP为67±28 mmol O m² d，超过了春季的26±13 mmol O m² d，主要是由于长江径流带来的营养物质输入。同时，在不受河流影响的CWCW中，夏季NCP为3²±21 mmol O m² d，春季和夏季之间的季节变化很小。为了评估生物泵的效率，我们首次在该区域使用O体外方法测量了净群落生产力（NCP）和总初级生产力（GPP）。（NCP/GPP）比值在YSW中为0.20至0.27，在CWCW中为0.21至0.26，表明效率相似。这些效率约为开阔海洋的两倍。CDW中的（NCP/GPP）为0.35，可能是由于夏季长江驱动的生产力增加。这种效率不仅接近全球上限，而且与受上升流和春季水华等偶发事件影响的区域相当，突出了CDW作为重要碳汇的潜力。这项研究为大陆架作为碳汇的作用提供了有价值的见解，并有助于减少陆架碳吸收的不确定性。此外，为了提高高分辨率观测的空间适用性，将 underway NCP数据与卫星衍生的海洋学变量相结合，开发了一个随机森林模型。这种方法强调了利用观测数据集估算大规模NCP的潜力，强化了大陆架在全球碳循环中的关键作用。
