Plastic trash transports microbes around the ocean, bringing disease to coral reefs

An international study revealed that plastic waste drifting in the ocean could adversely impact the corals it gets tangled with, as the material provides a favorable environment for microbial colonization. The study, which was published in the journal Science, investigated 159 coral reefs in the Asia-Pacific region to determine how the plastic debris affects the coral, as well as the likelihood of disease of a coral tangled with plastic.

• After surveying the reefs, the research team found that billions of plastic materials have been tangled in the reefs – with more spikey species getting tangled with more plastic materials.
• If a plastic latches itself onto a coral, it becomes prone to disease. In particular, the study reported that once this happens, the likelihood of the coral to get a disease increases by 20 times.
• This is because of the stress brought about by the plastic to the corals. In particular, it blocks the light source of the corals, leading to anoxic conditions which favor pathogen growth, as well as toxin release.
• In addition, corals are physically injured when they come in contact with plastic debris. This leads to abrasion, which opens up the coral to pathogen invasion. When this happens, the immune system of the coral may be compromised, allowing pathogens such as Halofolliculina corallasia to infect it and cause complications such as skeletal eroding band disease.
• The authors posited in their study that if these conditions continue, the amount of plastic that will impact the marine environment will skyrocket to 15.7 billion items, which will ultimately affect corals the world over.

Through this investigation, researchers opined that a decrease in the amount of plastic entering the ocean would be advantageous to coral reefs, especially as its chances of getting disease-associated mortality is reduced.

Find the full text of the study at this link.

Journal Reference:

Lamb JB, Willis BL, Fiorenza EA, Couch CS, Howard R, Rader DN, True JD, Kelly LA, Ahmad A, Jompa J, et al. PLASTIC WASTE ASSOCIATED WITH DISEASE ON CORAL REEFS. Science. 2018;359(6374):460–462. DOI: dx.doi.org/10.1126/science.aar3320