Dissolved organic matter (DOM) plays a vital role in promoting carbon and nutrient cycling. It is a food source for organisms and controls the migration and transformation of trace metals and other contaminants in aquatic systems. The contributions of aquatic DOM to the environment and ecology of a system are closely related to its abundance and chemical structure. In this study, the chemical composition and binding properties of DOM in a hypersaline lake watershed were investigated for the first time using dissolved organic carbon (DOC) analysis, absorption spectroscopy, Fourier transform infrared spectroscopy, pyrolysis-GC-MS (Py-GC-MS), and fluorescence parallel factor (PARAFAC) analysis combined with Pb(II) titration techniques. The results showed that DOM from the tributaries that flowed into the lake had a lower DOC content, higher molecular weight, and higher specific UV absorbance than the DOM in lake water. Protein-like fluorophores were mainly found in tributary and lake surface water DOM (LSDOM) and humic-like substances were abundant in lake groundwater DOM (LGDOM). Using this multi-methodological approach, we found that the DOM from the hypersaline lake watershed was mainly from microbial origins, and consisted of aromatics, carbohydrates, and aliphatics. The results from quantitative analysis showed that DOM from the inflowing tributaries contained more aromatics, lower carbohydrates, and lower aliphatics than DOM in the lake. Monocyclic aromatic hydrocarbons and carbohydrates were more abundant in LSDOM than LGDOM. The results from the Pb(II) titration technique coupled with PARAFAC analysis suggested that PARAFAC-derived components had relatively low condition stability constants (log K M <2). Of the two types of lake DOM, the LGDOM had a higher Pb(II) binding potential than the LSDOM. From this study we have improved our understanding of how DOM within a hypersaline lake watershed varies in its composition and potential to bind with metals.

Keli YANG;Yaoling ZHANG;Yaping DONG;Wu LI

Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China;Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources,Xining 810008,China;Qinghai Provincial Key Laboratory of Resources and Chemistry of Salt Lakes,Xining 810008,China

海洋湖沼学报（英文版）

[1]Keli YANG;Yaoling ZHANG;Yaping DONG;Wu LI-.Chemical composition and Pb(II) binding of dissolved organic matter in a hypersaline lake in China)[J].海洋湖沼学报（英文版）,2022(01):113-127

LSDOM,LGDOM,aliphatics,inflowing,Monocyclic

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