Plastic pollution on the world's coral reefs.

Coral reefs are losing the capacity to sustain their biological functions ¹ . In addition to other well-known stressors, such as climatic change and overfishing ¹ , plastic pollution is an emerging threat to coral reefs, spreading throughout reef food webs ² , and increasing disease transmission and structural damage to reef organisms ³ . Although recognized as a global concern ⁴ , the distribution and quantity of plastics trapped in the world's coral reefs remains uncertain ³ . Here we survey 84 shallow and deep coral ecosystems at 25 locations across the Pacific, Atlantic and Indian ocean basins for anthropogenic macrodebris (pollution by human-generated objects larger than 5 centimetres, including plastics), performing 1,231 transects. Our results show anthropogenic debris in 77 out of the 84 reefs surveyed, including in some of Earth's most remote and near-pristine reefs, such as in uninhabited central Pacific atolls. Macroplastics represent 88% of the anthropogenic debris, and, like other debris types, peak in deeper reefs (mesophotic zones at 30-150 metres depth), with fishing activities as the main source of plastics in most areas. These findings contrast with the global pattern observed in other nearshore marine ecosystems, where macroplastic densities decrease with depth and are dominated by consumer items ⁵ . As the world moves towards a global treaty to tackle plastic pollution ⁶ , understanding its distribution and drivers provides key information to help to design the strategies needed to address this ubiquitous threat.
(© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)