Relationship between lake salinity and the climatic gradient in northeastern China and its implications for studying climate change

The rising temperatures, increased evaporation, and altered precipitation patterns associated with global warming pose threats to aquatic ecosystems, especially the salinization of lake water and changes in the terrestrial carbon budget. We studied a series of samples of catchment soils, surface sediments, and sediment cores from 51 lakes and reservoirs covering an extensive climatic range in northeastern China. Measurements included salinity indices (electrical conductivity and pH) and other physicochemical parameters, including magnetic properties and color (chroma). The results indicate that the occurrence of salt minerals and the salinity of the lake sediments are dominated by the arid climatic conditions of the region. This enabled us to develop climatic transfer functions between salinity, precipitation and evaporation, with potential applications in paleoclimatic research. As carbonates are the dominant salts in most of the studied lakes and reservoirs, past salinity variations are likely reflected by changes in HCO3- and CO32- concentrations, which provides the opportunity to study the response of water-CO2-carbonate interactions to climate change. Our findings emphasize the important role of alkaline lakes in carbon burial and carbon neutralization, in the context of ongoing global warming. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that the salinity of lakes in northeastern China is mainly influenced by arid climatic conditions and transfer functions can be established to study the relationship between salinity, precipitation, and evaporation. Carbonates are the dominant salts in most lakes and reservoirs studied, with past salinity variations likely reflected by changes in HCO3- and CO32- concentrations.