As extremely active sites processing terrestrially derived dissolved organic matter (DOM), lakes deserve sufficient attention. Because of high-complexity interactions between DOM and the surrounding environment, the natural and anthropogenic drivers controlling the composition and chemodiversity of DOM molecules in lakes remain unclear. Here, 13,952 DOM molecules were identified and assessed in 45 lakes across China via ultrahigh-resolution mass spectrometry. Furthermore, the effects of both natural and anthropogenic factors on the DOM composition, DOM chemodiversity, and greenhouse gas emissions were investigated. The majority of the variations in DOM chemical composition could be attributed to the differences in the hydrology and nutrient concentrations of the lakes, and human activities also played a role, mainly through atmospheric pollution. Environmental factors mainly influenced DOM chemodiversity in the form of S-containing compounds. N-containing compounds exhibited a positive correlation with CO2 emissions, while N- and S-free compounds exhibited a positive correlation with N2O emissions. These results facilitate a comprehensive understanding of the interactions between lake DOM and the surrounding environment, thereby providing a reference for the formulation of strategies aimed at the harmonious development of human and natural environments.
Keywords: FT-ICR-MS; chemodiversity; dissolved organic matter; greenhouse gas emissions; human activities.