Scientists Discover Plastic Fused Onto Corals
Researchers surveying beaches in Japan's Ryukyu Islands found plastic that had melted directly into coral skeleton fragments, a new phenomenon they call "plasticoral".
While surveying beaches on Japan's Ryukyu Islands, researchers noticed small, brightly colored spots embedded in white coral gravel. After collecting samples from three beaches on the main island of Okinawa, lab analysis using spectroscopy revealed polymers derived from common household plastics.
Micro-CT scans showed the plastic had melted into microscopic pores within the coral skeleton fragments, becoming so thoroughly integrated that the two materials could no longer be separated. The researchers named this new conglomerate "plasticoral." While plastic has previously been found fused with nonliving materials like rocks, mussels, and algae in a phenomenon dubbed "plastiskin," this marks the first documented case of plastic fusing with coral.
Coral rubble, even after washing ashore, typically returns to the sea, where it provides a stable base for new coral growth and shelter for small marine organisms against currents and predators. Exactly how the plastic fuses with coral remains unclear — ocean temperatures aren't yet hot enough to melt plastic on their own, though ultraviolet radiation may play a role. The researchers consider beach bonfires the most likely cause.
The impact of plasticorals on living coral is not yet known, but prior research has shown that chemicals leaching from plastics can inhibit coral reproduction, and plastic fragments can carry pathogens to reefs. Further investigation is needed to confirm the bonfire theory, but given how widespread plastic pollution is, similar fusions may be occurring unnoticed on other beaches as well.
