Coral reefs form the building blocks for coastal ecosystems. Not only are these structures under assault from ocean acidification and a warming planet, but they are also prone to diseases caused by the proliferation of plastic waste found in the world’s oceans, according to a study put out last year by a team of international researchers.
The researchers surveyed 159 reefs in the Asia-Pacific region and estimated that billions of plastic items are entangled on the reefs in the region. One of the distressing findings in their report is that the likelihood for disease in these corals increased more than 20 fold once a coral is covered in plastic. This is due to the plastic essentially starving the coral of light, toxin release and anoxia, which enables pathogens to more easily attack corals.
“Plastic waste can promote microbial colonization by pathogens implicated in outbreaks of disease in the ocean,” the researchers wrote in their report. “We assessed the influence of plastic waste on disease risk in 124,000 reef-building corals from 159 reefs in the Asia-Pacific region. The likelihood of disease increases from 4% to 89% when corals are in contact with plastic.”
The researchers note in their paper that plastic waste has the capability to host pathogens that have proven to be triggers of disease outbreak in coral reefs. They said that a disease that colonizes polypropylene marine debris were dominated by an opportunistic pathogenic bacteria of the genus Vibrio, which has been implicated in the coral diseases known as White Syndrome, a disease that causes tissue loss in corals.
“Plastic waste associated with disease on coral reefs” can be read in its entirely on the Science website.