Glacier Meltwater Input and Salinity Decline Promote Algal Growth in a Tibetan Saline Lake

ABSTRACT Global warming has caused widespread shifts in lake hydrological conditions due to the increasing glacial meltwater input on the Tibetan Plateau. It is anticipated that favourable conditions for algal growth will be developed as a result of a rise in temperature, nutrient supply and salinity decline. However, the long‐term ecological process is rarely explored, and the underlying mechanism remains poorly understood. Here, we investigated Bangdag Co., a glacier‐fed and high‐salinity lake located in the northwest of the Tibetan Plateau, which has been experiencing a rapid expansion in recent decades. We reconstructed the algal community dynamics using sedimentary subfossil pigments to explore the lake's ecological trajectory over the past century. Combining remote sensing and regional instrumental data, we analysed how the lake ecosystem responds to climate warming, hydroclimatic change, and their interactions. Our results showed that pigment assemblages from total algae, chlorophytes, siliceous algae and cyanobacteria were well‐preserved and stable before the 2000s, followed by an accelerated abundance increase with lake expansion. Random forest and structural equation modelling analyses revealed that the rapid ecological shift was attributed to meltwater input, salinity decline and regional warming. Our analysis demonstrates that elevated salinity prior to 2000 hindered phytoplankton growth, suggesting that ongoing glacial melting and lake dilution are restructuring remote saline lake ecosystems in a warming world. This study improves the understanding of primary producer succession inhabiting hypersaline environments with rapid hydrological shifts on the Tibetan Plateau, emphasising the significant impact of lake expansion induced by glacial meltwater on ecosystem dynamics.