Shedding new light on coral Black Band Disease

by Kim Spurr, University of North Carolina at Chapel Hill
July 12, 2022

UNC-Chapel Hill biologists examine the links between microbial mats and a type of coral disease that has become an urgent conservation concern, and they suggest mitigation strategies to help reduce its spread. Coral reefs are valuable to marine ecosystems and the global economy.

The College of Arts and Sciences talked with Sophie McCoy, assistant professor of biology in the College of Arts and Sciences, and Ph.D. candidate Ethan Cissell about their research published in the journal Ecological Applications.

What’s the overall value of coral reefs to marine ecosystems and to the economy?

It is easy to care about corals, which are such beautiful and charismatic animals. However, corals also play a truly outsized role in the provision of concrete ecosystem services across the world. Corals provide the skeleton or underwater skyline of reefs that are home to many other sedentary organisms, like sponges and octocorals that are valuable for water filtration and natural products, and that are also used by fish — including fisheries species. Physically, coral structures attenuate waves and flooding from storms, protecting shorelines from flooding and erosion. Finally, healthy reefs are the backbone of lucrative tourism industries around the world, including in the United States.

The increasing prevalence of coral diseases is an urgent conservation concern. What did you find? 

Coral diseases are becoming more common on coral reefs globally. Coral disease outbreaks can devastate entire populations of critically endangered corals. This threatens the physical and economic services that reefs provide, including shoreline protection and food security. To work toward disease prevention, we also need to understand what aspects of coral reefs promote the survival and spread of disease-causing pathogens.

In this study, we identified benthic cyanobacterial mats as a possible refuge for Black Band Disease pathogens on coral reefs. Benthic cyanobacterial mats are microbial mats that grow on the sea floor in association with photosynthetic cyanobacteria, which are also called blue-green algae. Similar mats are also found in freshwater systems. On coral reefs, benthic cyanobacterial mats have been spreading globally, and they are related to water column cyanobacterial blooms that have become problematic along many coastlines.

This paper identifies and describes priority research areas to specify links between cyanobacterial mats and coral Black Band Disease. We also discuss next steps toward developing mitigation strategies to help reduce the spread of Black Band Disease.

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Read the Ecological Applications paper: