Microplastics impair growth in two atlantic scleractinian coral species, Pseudodiploria clivosa and Acropora cervicornis.

Scleractinian coral are experiencing global and regional stressors. Microplastics (<5 mm) are an additional stressor that may cause adverse effects on coral. Experiments were conducted to investigate ingestion size limits and retention times of microspheres in a two-day exposure as well as observing growth responses in a 12-week exposure in two Atlantic species, Pseudodiploria clivosa and Acropora cervicornis. In the two-day exposure, P. clivosa ingested a higher number of microspheres ranging in size from 425 μm-2.8 mm than A. cervicornis. Both species egested the majority of microspheres within 48 h of ingestion. In the long-term exposure, calcification and tissue surface area were negatively affected in the treatment group of both species. Exposure also negatively affected buoyant weight in A. cervicornis but not in P. clivosa. The results indicate that microplastics can affect growth responses, yet additional research is warranted to investigate potential synergistic impacts of microplastics and other stressors.