Plastic waste in the ocean makes reef-building corals highly vulnerable to several potentially fatal diseases.

Joleah Lamb at Cornell University in Ithaca, New York, and her colleagues surveyed 159 reefs in the Asia-Pacific region for signs of disease and plastic pollution, and discovered a dramatic correlation: the likelihood of disease on a coral free of plastic waste was only 4%, but jumped to 89% on a coral blighted by plastic.

The debris might act as a vector for white syndrome, which destroys coral tissue, because the bacteria that trigger outbreaks of the disease are good at colonizing plastic. The low-light, low-oxygen conditions created when plastics settle on coral are also hospitable to the microbes that cause black-band disease, another often-lethal condition.

Plastic seems to be particularly destructive to branching and structurally complex species of coral, which provide crucial habitats for fisheries in the Asia-Pacific region, according to the authors.