New Pollution Type ‘Plasticoral’ Found Fusing with Coral in Japan

Researchers have identified a novel form of marine pollution in which plastic waste becomes permanently fused with coral fragments. Coined “plasticoral,” this phenomenon was discovered during a survey of coastal areas in Japan’s Ryukyu Islands, specifically on Okinawa. The findings, published in a recent study, highlight a previously unrecognized way in which plastic debris is integrating into marine ecosystems.

The discovery originated when scientists observed small, brightly colored spots embedded within white coral gravel on three beaches on the main island of Okinawa. Upon collecting samples and subjecting them to spectroscopic analysis, researchers confirmed the presence of polymers derived from common household plastics. Further examination using micro-CT scans revealed that these polymers had melted into the microscopic pores of the coral skeleton fragments, creating an inseparable bond between the two materials.

This is not the first instance of plastic merging with natural elements; in 2019, researchers identified “plastiskin,” a degraded plastic coating on mussels and algae in tide pools. However, the new study marks the first documented case of plastic fusing with coral. The image provided by the researchers shows plasticoral collected at Chosu Beach and Ibe Beach within Yanbaru National Park, as well as a sample found near a bonfire site on Chushu Beach, suggesting a potential link between beach fires and the fusion process.

While the coral rubble itself is no longer living tissue, it plays a critical role in reef ecosystems. Once washed ashore, these fragments often return to the sea, where they provide a stable foundation for new corals to settle and offer shelter for small marine organisms from predators and strong currents. The implications of plasticoral for these living ecosystems remain unclear, though previous studies indicate that chemicals leaching from plastics can inhibit coral reproduction and that plastic fragments may introduce pathogens.

Scientists are still investigating the exact mechanism behind the fusion. Although ocean temperatures are rising, they are not currently high enough to melt plastic on their own. Ultraviolet radiation may contribute, but researchers suspect that beach bonfires are the primary cause. The sample found near a bonfire site supports this hypothesis, indicating that discarded plastic waste exposed to intense heat from fires likely melted and fused with the coral rubble. This discovery adds a new dimension to the ongoing crisis of marine plastic pollution, which is estimated to involve several million metric tons of waste on the seafloor globally.