Prolonged light exposure time enhances the photosynthetic investment in osmotrophic <i>Ochromonas</i>

Mixotrophs possess flexible metabolism modes and multiple ecological roles, making them sensitive to environmental changes. Due to their widespread distribution and unique nutritional strategy, they serve as key functional groups in marine and freshwater ecosystems, with significant roles in global biogeochemical cycles. Photoperiod, a critical environmental cue, regulates circadian rhythms and may influence the metabolic strategies of mixotrophs. Therefore, this study focused on how the mixotrophic microorganisms <i>Ochromonas gloeopara</i> adjusted autotrophic and osmotrophic pathways in response to photoperiodic changes. These findings highlight the metabolic flexibility of mixotrophic organisms in response to photoperiodic changes, providing new insight on how mixotrophs regulate the flow of materials and reshape the food web structures. This research offers valuable and innovative perspectives for understanding the functional roles of mixotrophic microorganisms in ecosystems, with important implications for improving the accuracy of global carbon cycle predictions.