<b>Biogeographic reorganization of eukaryotic ultraphytoplankton under warming: winners, losers, and risk hotspots in China’s lakes</b>

Using ZOTU-level thermal optima and tolerance ranges, projections indicate national richness losses of approximately 34–48% by 2100, with loss hotspots concentrated in the Eastern Plain, whereas plateau lakes would act as recipient refugia. Under continued warming, small, fast-growing chlorophyte phototrophs are projected to emerge as relative ‘winners’, but larger mixotrophs as relative ‘losers’, thereby potentially lowering trophic transfer efficiency and weakening carbon sequestration in China’s lakes.

This database and thermal-niche framework provide a foundation for forecasting and managing warming-driven redistribution of ultraphytoplankton, with implications for biodiversity conservation, water quality, and inland-water carbon budgets.</a></p>