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

Area of Science:

• Environmental Science
• Limnology
• Biogeochemistry

Background:

• Dissolved organic matter (DOM) is vital for the global lake carbon cycle.
• Previous research primarily focused on freshwater lakes, neglecting saline lake ecosystems.
• Understanding DOM dynamics is key for carbon cycling, pollution control, and water resource management.

Purpose of the Study:

• To investigate dissolved organic matter (DOM) composition in saline lakes of northwestern China.
• To quantify the influence of environmental factors, including human activities and salinity, on DOM.
• To develop a method for remote estimation of DOM in saline lakes.

Main Methods:

• In situ data collection from ten lakes in northwestern China.
• Parallel factor analysis (PARAFAC) applied to excitation-emission matrices (EEMs) to identify DOM fluorescence components.
• Generalized linear model (GLM) used to determine the contributions of environmental factors to DOM variations.

Main Results:

• Eutrophication index positively correlated with dissolved organic carbon (DOC) and colored DOM (CDOM).
• Terrestrial humic-like and tryptophan-like DOM components, linked to human activities, explained significant variations in DOC and CDOM.
• Salinity showed a strong positive correlation with DOC and CDOM, indicating increased DOM concentrations in saline conditions.

Conclusions:

• Human activities and salinity are the primary drivers of DOM concentration and composition in arid saline lakes.
• Salinization increases DOM levels, with significant contributions to DOC and CDOM variations.
• Findings support remote sensing approaches for monitoring DOM in saline lakes, aiding carbon cycle studies and water resource protection.