Vertically stratified water source characteristics and associated driving mechanisms of particulate organic carbon in a large floodplain lake system

Shuoyue Wang; Yang Gao; Junjie Jia; Yao Lu; Kun Sun; Xianrui Ha; Zhaoxi Li; Wanqian Deng

doi:10.1016/j.watres.2021.117963

Vertically stratified water source characteristics and associated driving mechanisms of particulate organic carbon in a large floodplain lake system

Water Res. 2022 Feb 1:209:117963. doi: 10.1016/j.watres.2021.117963. Epub 2021 Dec 15.

Authors

Shuoyue Wang¹, Yang Gao², Junjie Jia¹, Yao Lu¹, Kun Sun³, Xianrui Ha¹, Zhaoxi Li¹, Wanqian Deng¹

Affiliations

¹ 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.
² 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. Electronic address: gaoyang@igsnrr.ac.cn.
³ University of Chinese Academy of Sciences, Beijing, 100049, PR China.

PMID: 34933159
DOI: 10.1016/j.watres.2021.117963

Abstract

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 (δ¹³C and δ¹⁵N) 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 C₃ 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.

Keywords: Lake Poyang; Particulate organic carbon; Source; Stable carbon and nitrogen isotopes; Vertical stratification.