Eutrophication and salinization elevate the dissolved organic matter content in arid lakes

Xintong Jiang; Dong Liu; Junli Li; Hongtao Duan

doi:10.1016/j.envres.2023.116471

Eutrophication and salinization elevate the dissolved organic matter content in arid lakes

Environ Res. 2023 Sep 15:233:116471. doi: 10.1016/j.envres.2023.116471. Epub 2023 Jun 20.

Authors

Xintong Jiang¹, Dong Liu², Junli Li³, Hongtao Duan⁴

Affiliations

¹ School of City and Environment, Northwest University, Xi'an, 710127, China; Key Laboratory of Watershed Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; Shanxi Key Laboratory of Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, 710127, China.
² Key Laboratory of Watershed Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China. Electronic address: dliu@niglas.ac.cn.
³ Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Xinjiang, 830011, China.
⁴ School of City and Environment, Northwest University, Xi'an, 710127, China; Key Laboratory of Watershed Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; Shanxi Key Laboratory of Surface System and Environmental Carrying Capacity, Northwest University, Xi'an, 710127, China. Electronic address: htduan@niglas.ac.cn.

PMID: 37348635
DOI: 10.1016/j.envres.2023.116471

Abstract

Dissolved organic matter (DOM) plays an essential role in the global lake carbon cycle. Understanding DOM composition and monitoring its spatiotemporal dynamics are of great significance for understanding the lake carbon cycle, controlling water pollution, and protecting water resources. However, previous studies have focused mainly on eutrophic freshwater lakes, with limited attention given to saline lakes. Based on in situ data collected in ten lakes in northwestern China, this study reported the changes in DOM components in different lake types. Parallel factor analysis (PARAFAC) was used to analyze the three-dimensional excitation emission matrix (EEMs) to obtain the DOM fluorescence components. The contributions of different environmental factors to the changes in DOM components were quantified by the generalized linear model (GLM). The results showed that the eutrophication index was significantly positively related to dissolved organic carbon (DOC) (R² = 0.95, p < 0.01) and colored DOM (CDOM) (R² = 0.96, p < 0.01) concentrations. Terrestrial humic-like and tryptophan-like components, which are highly correlated with human activities, explained 62% and 64% of the variations in DOC and CDOM, respectively. In sum, the contributions of human activities to the DOC and CDOM variations were 61% and 57%, respectively. Salinity also showed significant positive correlations with both DOC (R² = 0.88, p < 0.01) and CDOM (R² = 0.87, p < 0.01). Lake salinization led to increases in DOM concentration, and salinity contributed 20% and 16% to the DOC and CDOM variations, respectively. Therefore, human activities and salinity codetermined the DOM concentration and its composition in the western arid lakes. Based on these findings, this study proposed a feasible flowchart for remotely estimating DOM in saline lakes using satellite data. This study is significant for the long-term monitoring of the carbon cycle and the effective protection of lake water resources in saline lakes.

Keywords: Anthropogenic activities; Dissolved organic matter; Eutrophication; Impact factors; Saline lake.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon Cycle
China
Dissolved Organic Matter*
Eutrophication
Humans
Lakes*
Spectrometry, Fluorescence

Substances

Dissolved Organic Matter