Kim Dongyoung, Kim Tae-Hoon, Kang Chang-Keun, Park Hyun Je
Department of Marine Ecology and Environment, Gangneung-Wonju National University, Gangneung, 25457, Republic of Korea; East Coast Life Sciences Research Institute, Gangneung-Wonju National University, Gangneung, 25457, Republic of Korea.
Department of Oceanography, Faculty of Earth Systems and Environmental Sciences, Chonnam National University, Gwangju, 61186, Republic of Korea.
Mar Environ Res. 2025 Sep;210:107238. doi: 10.1016/j.marenvres.2025.107238. Epub 2025 May 31.
The river transports dissolved and particulate matter to the estuary, where physical and biogeochemical transitions occur. In the river-estuary transition zone (RETZ), phytoplankton response is an effective indicator of environmental variability with their immediate responses. Here, we examine summer-monsoonal variability in productivity and nitrogen uptake of phytoplankton in three major Korean rivers and their estuaries: the Han, Geum, and Yeongsan. Results showed that summer-monsoonal variability of primary productivity in dam-constructed RETZ divided them into riverine zone governed by nutrient-phytoplankton interactions and estuarine zone associated with nitrogenous substrate dynamics. In contrast, free-flowing RETZ exhibited lower variability in phytoplankton productivity due to simultaneously enhanced nitrogenous nutrients and turbidity. Our generalized additive model analysis indicated that composition of particulate organic matter is primarily correlated with phytoplankton biomass associated with light availability. Our findings emphasize the complex interplay of physical and biogeochemical processes in RETZ, mainly influenced by monsoonal variability and river-estuary connectivity.
河流将溶解物质和颗粒物输送到河口，在那里会发生物理和生物地球化学转变。在河海过渡区（RETZ），浮游植物的反应因其即时反应而成为环境变化的有效指标。在此，我们研究了韩国三条主要河流及其河口（汉江、锦江和荣山江）中浮游植物生产力和氮吸收的夏季季风变化。结果表明，建有大坝的河海过渡区初级生产力的夏季季风变化将它们分为受营养物 - 浮游植物相互作用控制的河川区域和与含氮底物动态相关的河口区域。相比之下，自由流动的河海过渡区由于同时增强的含氮养分和浊度，浮游植物生产力的变化较小。我们的广义相加模型分析表明，颗粒有机物的组成主要与与光照可用性相关的浮游植物生物量相关。我们的研究结果强调了河海过渡区物理和生物地球化学过程的复杂相互作用，主要受季风变化和河海连通性的影响。
