Transcriptomic Insights into the Life-History and Population Responses of Brachionus plicatilis to Artificial Light at Night.

Artificial light at night (ALAN), intensified by coastal urbanization, is an emerging threat to coastal ecosystems. We used the rotifer Brachionus plicatilis and its prey Phaeocystis globosa as a model predator-prey system to examine rotifer life-history traits, predator-prey dynamics, and transcriptomic responses under varying ALAN intensities. ALAN altered maturation timing without affecting lifespan, and it reduced fecundity, population growth, and clearance rate, thereby delaying the depletion of P. globosa. Transcriptomic and network analyses showed that rotifers exposed to ALAN exhibited altered expression of candidate regulatory genes, including cytoskeleton-associated protein 5 (ckap5) and Raf proto-oncogene, serine/threonine kinase (raf) family members. These changes were associated with a CKAP5-associated microtubule module, RAF/PKA-related signaling, reproductive and cell-cycle-related pathways, and FoxO/autophagy-associated cellular-maintenance processes. These molecular responses provide potential regulatory clues for interpreting the phenotypic changes observed under ALAN exposure. Our findings help evaluate the potential effects of ALAN on zooplankton performance, and provide a scientific basis for assessing the environmental risks of coastal light pollution.