Heatwave amplifies HFPO-DA toxicity in Chlorella vulgaris via energetic misallocation and proteasome disruption:...

Climate warming and emerging pollutants both pose serious threats to aquatic ecosystems, yet the combined effects of heatwave (HW) and perfluorinated compounds remain poorly understood. This study demonstrated that HW (30°C vs 25°C) exacerbated hexafluoropropylene oxide dimer acid (HFPO‑DA, also known as GenX) toxicity on Chlorella vulgaris by integrating physiological, interfacial, multi‑omics, and computational analyses. While stimulating a 75% growth increase, HW amplified the growth inhibition caused by HFPO-DA by inducing oxidative damage and membrane disruption, and suppressed photosynthetic compensation. HW altered algal-HFPO-DA binding priorities, the extracellular polymeric substances composition, and compacted secondary protein structures, resulting in a 34.9-55.1% reduction in HFPO-DA adsorption. Multi-omics and physiological profiling further revealed that combined stress caused severe depletion of energy reserve (40.3-55.5% loss in proteins, polysaccharides and lipids) and disrupted key metabolic processes, including amino acid metabolism and energy transduction. HW also altered the algal defense strategy against HFPO-DA by reversing its transcriptional regulation of photosynthesis from compensatory upregulation to suppression, and disrupting protein homeostasis. Our findings support the integration of HW into toxics risk assessment and the development of dynamic models as critical for predicting hazards in warming aquatic systems.