Plastic trash entangled on reefs across the world is making the coral sick, according to a new study carried out by an international team of researchers from the U.S., Canada, Australia, Indonesia, Thailand, and Myanmar. The study claims that the plastic waste that gets into the oceans allows bacterial pathogens to make their colonies within the reefs, thereby disturbing the health of the delicate coral tissues and making them sick.

According to The International Coral Reef Initiative, corals are tiny invertebrates that belong to a large group of colorful animals called Cnidaria. These little organisms create “apartments” or reefs by clinging to one another. Corals extract calcium from the seawater and use it to create a hardened structure that protects them from other marine creatures.

Coral reefs are believed to play an important role in maintaining the good health of marine ecosystems. They allow nutrients to move through the food webs in the oceans. They create important habitats for several marine organisms and protect coastlines from erosion, waves, and storms. Coral reefs are also vital for more than 270 million people who depend on these reefs for food and income.

In the past few years, the deteriorating health of the coral reefs across the world has grabbed the attention of scientists as well as environmental groups. Coral bleaching due to climate change and overfishing has already done huge damage to different coral reefs. The new finding that plastic waste is adding to the burden of climate-related diseases in coral reefs could now be another cause of worry for scientists.

Plastic is a synthetic material that is used to make a large number of products. However, it is a non-biodegradable material that may take hundreds or thousands of years to degrade completely. According to Cbc.ca, a 2015 study estimated that roughly 4.8–12.7 million tons of plastic—in the form of bags, disposable diapers, snack wrappers, etc.,—reached the world’s oceans in 2010 alone. Scientists estimate that by 2025, nearly 15.7 billion plastic items would have reached the marine environment, thus polluting even the outermost corners of the oceans.

Billions of plastic pieces are infecting coral reefs with diseases, study shows https://t.co/U5LmEICqXs — TIME (@TIME) January 26, 2018

In the current study, researchers carried out a four-year survey of nearly 125,000 corals on 159 reefs in the Asia-Pacific region. The team examined plastic-free as well as plastic-contaminated coral reefs in Australia, Indonesia, Thailand, and Myanmar. Deep analysis of these reefs revealed that corals contaminated with plastic waste had an 89 percent chance of getting sick with three nasty diseases: (1) black band disease, (2) white syndrome, and (3) skeletal eroding band disease.

In comparison, corals that were free of plastic waste had just 4 percent chance of being infected with a disease.

Researchers explain that plastics items, such as bottle caps and toothbrushes commonly made of polypropylene, are ideal for bacteria to make their colonies. When these bacteria come into contact with corals, they spread deadly coral diseases. Plastic litter was also found to impact corals by releasing toxins and depriving them of the sunlight.

Joleah Lamb, a postdoctoral research fellow at Cornell University in New York and the lead researcher of the study, says that once a coral gets a disease, the infection spreads across the colony.

“What’s troubling about the coral disease is that once the coral tissue loss occurs, it’s not coming back,” said Lamb.

According to Lamb, this research shows that cutting the amount of “plastic waste entering the ocean will have direct benefits to coral reefs.”

The detailed findings of the study were published in the journal Science.