Warming Patterns Shape Divergent Multilevel Physiological Responses and Underlying Metabolic Mechanisms in Aquatic Organisms

Although the impacts of global warming on aquatic ecosystems are widely recognized, the biological consequences of distinct warming patterns remain largely unknown. We investigated physiological and metabolic responses of Daphnia magna, Chironomus kiiensis, and zebrafish under constant warming (+1, +3 °C), heatwave, and temperature fluctuation. Dynamic patterns exhibited stronger physiological responses, with mean absolute effect sizes across survival, growth, development, behavior, and stress functional categories following the order heatwave > fluctuation > +3 °C > +1 °C. Response profiles varied among warming patterns: constant +3 °C induced moderate and broad changes across biochemical stress, developmental, and behavioral end points; heatwave accelerated zebrafish hatching and C. kiiensis pupation while increasing deformity, suppressing growth, and elevating mortality; and fluctuation induced pronounced biochemical stress responses, particularly HSP70, together with developmental disruption, while producing weaker survival and growth effects than heatwave. Across taxa, dominant response profiles differed, with broad multiend point disruption in D. magna, stress-dominant responses in C. kiiensis, and developmental sensitivity in zebrafish. Metabolomic analysis further identified warming-pattern-specific metabolic signatures associated with energy metabolism under +3 °C, membrane-related processes under heatwave, and redox-related processes under fluctuation. Together, these findings provide a scientific basis for improving aquatic ecological risk assessment under increasingly variable warming scenarios.