Wang Shuoyue, Gao Yang, Jia Junjie, Lu Yao, Sun Kun, Ha Xianrui, Li Zhaoxi, Deng Wanqian
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
Water Res. 2022 Feb 1;209:117963. doi: 10.1016/j.watres.2021.117963. Epub 2021 Dec 15.
Particulate organic carbon (POC) is an important component of lake organic carbon (C) pools, of which different factors drive vertical distributions and sources. This study used the dual stable isotope (δC and δN) approach to investigate vertical POC sources and drivers in a large floodplain lake system. Findings showed that POC composition gradually changed from endogenous dominant to exogenous dominant sequentially from the surface layer to the bottom layer of Lake Poyang. Environmental factors associated with phytoplankton photosynthesis as well as nutrient levels primarily drove surface POC. Moreover, soil erosion, sediment deposition, and resuspension strongly affected POC distribution and composition in the middle and bottom layers of the lake. POC sources were also affected by factors associated with vertical mixing, such as wind speed and water depth. Litter from C plants significantly contributed to POC concentrations in the middle and bottom layers of the lake. Results from this study can benefit our overall understanding of the potential driving mechanisms of lake C cycling processes, aquatic ecosystem functions, and pollutant migration.
颗粒有机碳（POC）是湖泊有机碳（C）库的重要组成部分，其垂直分布和来源受不同因素驱动。本研究采用双稳定同位素（δC和δN）方法，调查了一个大型洪泛平原湖泊系统中POC的垂直来源及驱动因素。研究结果表明，鄱阳湖从表层到底层，POC组成逐渐从以内源为主转变为以外源为主。与浮游植物光合作用以及营养水平相关的环境因素主要驱动表层POC。此外，土壤侵蚀、沉积物沉积和再悬浮强烈影响湖泊中层和底层的POC分布及组成。POC来源还受到与垂直混合相关的因素影响，如风速和水深。C植物的凋落物对湖泊中层和底层的POC浓度有显著贡献。本研究结果有助于我们全面了解湖泊碳循环过程、水生生态系统功能及污染物迁移的潜在驱动机制。
