Plastic fused to coral rubble raises new concerns for ocean pollution

Researchers from the University of the Ryukyus found five pieces of plastic thermally fused to coral rubble on beaches on Okinawa Island during an August 2024 litter survey, coining the term plasticoral for the phenomenon. Lab analysis identified the plastics as polyethylene and polypropylene, common materials in bottles and food containers, likely melted into the rubble by a beach fire.

The team says this differs from previously documented plastiglomerates because the melted polymer conformed to and permanently bonded with the coral's porous skeleton rather than merely sticking to rock or wood. Burning plastic releases dioxins and can accelerate the material's breakdown into microplastics, both flagged as health and habitat concerns in the study.

Coral rubble, even dead, supports small invertebrates and colonizing algae that larger species depend on, and the researchers say plastic-sealed rubble may no longer function as usable habitat. With an estimated 199 million tons of plastic already in the ocean, the team hopes documentation efforts, including tracking litter like plasticoral, will expand with public help.

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