In addition to unprecedented bleaching events, habitat degradation, and ocean acidification, coral reefs have been suffering huge losses due to diseases long attributed to bacterial infections. The numbers are staggering: 70 to 80% of some Caribbean coral reefs have been killed by one such disease known as the white plague, which affects 33 Caribbean species. The plague, which is characterized by a separation of healthy tissue from the coral skeleton, can decimate a coral colony within days of the initial infection. Reported incidents of such diseases have been steadily increasing for decades.
The white plague has been observed on coral reefs since the 1970s, and it has long been believed that a bacteria known as Aurantimonas coralicida is responsible. With the number of infected corals continuing to grow, researchers in the College of Science at Oregon State University have been working to understand the disease and its effects on corals.
According to findings published in the International Society for Microbial Ecology Journal, OSU researchers have made a breakthrough discovery: the white plague is not always caused by bacteria. In fact, some corals colonized by A. coralicida have not become infected with the plague. Rather, Caribbean outbreaks of the disease may be caused by small, circular, single-strand DNA viruses. It is still unknown whether the virus attacks the coral itself or the algal symbiont, and links to stressors such as increased ocean temperatures and overfishing have yet to be fully understood. However, for the sake of coral reefs and related marine ecosystems, researchers continue towards understanding the plague and potential opportunities to slow the loss of coral reefs in the Caribbean and throughout the world.
By Kristen Daly