Developmental temperature modulates microplastics impact on amphibian life history without affecting ontogenetic microplastic transfer

Abstract

This study examines how temperature influences the response of Japanese tree frogs (Dryophytes japonicus) to microplastic (MP) pollution, assessing whether temperature can regulate the harmful effects of MPs on their life history and the dispersal of MPs across habitats. This analysis aims to understand the ecological and physiological ramifications of MP pollution. Our results demonstrated an ontogenetic transfer of MP particles across amphibian metamorphosis, possibly allowing and facilitating the translocation of MPs across ecosystems. Temperature did not significantly affect the translocation of aquatic MPs to land. However, high temperatures significantly reduced mortality and hindlimb deformities caused by MPs, thereby mitigating their harmful impact on amphibian life histories. Importantly, our study found that MPs cause hindlimb deformities during amphibian metamorphosis, potentially linked to oxidative stress. Additionally, MP exposure and ingestion induced a plastic response in the morphology of the digestive tract and changes in the fecal microbiome, which were evident at high temperatures but not at low temperatures. The effects of MPs persisted even after the frogs transitioned to the terrestrial stage, suggesting that MPs may have complex, long-term impacts on amphibian population sustainability. Our results enhance the understanding of the intricate environmental challenges posed by MPs and underscore the significant role of temperature in ectotherms regarding ontogenetic impacts and pollutant interactions.