Coral reefs are dying in the Caribbean. It’s especially alarming in the Turks and Caicos because the cause appears to be a rapidly-spreading new disease that started in Florida.
WHQR talks with UNCW’s Frank Hawkins Kenan Distinguished Professor of Marine Biology Joe Pawlik about his dive trip in January to the region and why it’s so hard for scientists to identify the pathogen causing the disease.
RLH: Before I turned on the mics, you said that this is analogous to the wildfires in Australia.
RLH: Is that hyperbolic?
Joe Pawlik: Not at all. Imagine if no one lived in Australia and we went and visited there, you know, occasionally and wildfires went across the continent. And on the next visit it was like, wow, what happened? That's basically how we perceive the marine environment. We don't live there. And in many cases, these reefs are far from human habitation.
RLH: You traveled to the Turks and the Caicos in January 2020, and you shot the footage that we see on your website showing these coral reefs off the coast of the Turks and the Caicos.
RLH: There are no land-based sources of pollution there, right? Which is what leads you to believe this is a result of what we're calling Stony Coral Tissue Loss Disease.
JP: Correct… And the first dive of that particular trip, I went down and I was stunned to see that the live coral cover was almost completely gone and very recently gone. And what little coral was left was really badly bleached. So basically the skeletons of the corals were white. And you could tell that all of this had happened within just months because the tissue was just fresh off the skeletons, just recently colonized by algae and other things. So it was very much death in process.
RLH: What is the cause of Stony Coral Tissue Loss disease?
JP: We don't know. In fact, this is true for almost all coral diseases. We don't have a specific pathogen we can point to. It appears to be either that it's a multiple pathogen effect or that the stress level for the coral is such that normal invasive pathogens that are always present in the environment attack the coral. The difference in this particular case though, is that we really can trace this to the beginnings of a pathogenesis that started in Florida in 2014 and is now rapidly progressing across the Caribbean.
RLH: Do you have any idea why this is happening?
JP: As yachts and vessels move from place to place, they exchange water from one location to another and it's thought that maybe that's what's moving it across the Caribbean. There’s no evidence to prove that, but that's a really interesting hypothesis for why it's moving the way that it is.
RLH: Is water temperature one of the factors in Stony Coral Tissue Loss Disease?
JP: We think so because the comments from the people who have watched the progression of this disease, and this is an interesting phenomenon that it turns out that it is reduced at higher temperatures and that is kind of the opposite of what you might expect because corals tend to be more stressed at higher temperatures.
RLH: The disease is reduced?
JP: Right, at higher temperatures. It seems as though it shuts it down. And that is very strange because one of the hypotheses was that this particular disease may be part and parcel with the stress of higher temperatures, but that does not seem to be the case. Now in the case of the reefs on the West side of the Turks and Caicos, unfortunately in 2019 or last fall, the seawater temperatures got so high that the corals that weren't affected by this disease bleached.
RLH: What do you want non-scientists to take from this?
JP: If I had to point out one thing that people could do is flush their ballast water before they moved from place to place in the Caribbean to slow the progress of this particular disease.
RLH: Joe Pawlik, Distinguished Professor of Marine Biology at the University of North Carolina Wilmington, thank you so much for talking with us today.
JP: You’re very, very welcome, Rachel.
Follow this link to see video of the reefs off the Turks and Caicos: