Seagrass Under Siege? Investigating the Effects of Microplastics on Eelgrass (Zostera muelleri) in a Laboratory-Controlled Mesocosm Study

sediment), but significant declines in biomass (72-86%), rhizome length (110-190%), and leaf count (8-10 fewer leaves) under elevated microplastic loads. Photosynthetic (Y-Yield) efficiency was not affected, and sediment microbiomes exhibited resilience, with no significant shifts in diversity. Chemical analyses identified 82 leachates in sediments, including ten unique to treatments spiked with microplastics, suggesting leachate toxicity may be related to observed biological impacts. These findings suggest that Z. muelleri may be resilient to microplastic pollution at current observed concentrations but are likely to be negatively affected if microplastic pollution continues to rise. Research on leachate-specific effects is required for targeted mitigation strategies to help conserve these vital ecosystems.