Gene Yang ‘19

275 million people rely on coral reefs for food, coastal protection, and income from tourism. However, as plastic waste continues to spread throughout the ocean, it transmits disease to these same coral reefs. In the first large-scale study to evaluate this impact of plastic on corals, Dr. Joleah Lamb’s team from Cornell University along with other research teams and institutions surveyed 124,884 corals in 159 coral reefs in Asia-Pacific—a region that contains 50% of the world’s coral reefs. By visually examining coral colonies, the researchers found the chance of corals exposed to plastic waste getting disease was increased from 4% to 89% when compared to plastic-free corals. In particular, plastic debris was 8 times more likely to affect structurally complex corals. While very large coral colonies were the least likely to maintain contact with plastic waste, they showed the greatest increase in disease risk, up to 98%, when exposed to plastic.

Three particularly-lethal coral diseases that increased in the presence of plastic were also identified: skeletal eroding band disease (24% increase), white syndrome (17%), and black band disease (5%). Although the exact biological mechanism of how plastic increases disease risk is a topic of ongoing research, we know that plastic waste can cause physical injury in coral tissue, leading to invasion of pathogens.

The researchers also used the data obtained from their survey, the total plastic waste per geographical region, and estimated with 95% confidence that 11.1 billion plastic items currently are spread across Asia-Pacific coral reefs. Notably, this number is likely underestimated, as it did not include regions near China or Singapore. By 2025, this number is likely to increase to 15.7 billion, which will have a noticeable impact to the $375 billion worth of goods and services provided by coral reefs annually. The results of this study highlight the increasing need of improved waste management in order to preserve our coral reef ecosystems.

References

1. J. Lamb, et al., Plastic waste associated with disease on coral reefs. Science 359, 460-462 (2018). doi: http://10.1126/science.aar3320.
2. Image retrieved from: https://cdn.pixabay.com/photo/2017/08/19/19/28/fish-2659613_1280.jpg