Without a doubt, around the world, coral reefs are facing trouble. Rising ocean temperatures have stressed the reefs, bleaching the corals and leaving them weakened and susceptible to disease. Now, the Florida Department of Environmental Protection (FDEP), along with federal, state and local groups are struggling to combat the mysterious disease.
Officials have been working on documenting the extent of the disease since before 2014, trying to identify the likely pathogen, find a treatment, and address underlying problems. But to date, no identification has been forthcoming. Scientist William Precht, one of the first scientists to spot the disease, was hired by the state to monitor the health of reefs off the port of Miami.
He has watched helplessly as the disease has moved from one patch of coral to the next. He says the disease has proved to be especially deadly to species of brain and star coral, which form the foundation for many reefs.
“This is essentially equivalent to a local extinction, an ecological extirpation of these species locally,” he says. “And when you go out and swim on the reefs of Miami-Dade County today, it would be a very rare chance encounter that you’d see some of these three or four species.”
According to the FDEP, the disease outbreak has become widespread and is estimated to have resulted in the mortality of millions of corals. In fall 2014, isolated sites with significant coral disease were reported near Key Biscayne in Miami-Dade County by the FDEP’s Coral Reef Conservation Program staff as well as local scientists.
By the fall of 2015, the disease was confirmed across approximately 55 linear miles of reef, including locations as far north as Pompano Beach in Broward County and as far south as Biscayne National Park, with additional pockets of diseased coral in Palm Beach County.
In the summer of 2017, reports of widespread disease were confirmed as far north as St. Lucie Inlet in Martin County and to the southern boundary of the upper Keys.
Multiple contributing factors are involved
Usually, coral diseases are caused by some sort of stressor, either biological, like bacteria, fungi, and viruses. There are also nonbiological stressors, like rising sea temperatures, ultraviolet radiation, and pollutants. You could put part of the blame on global warming, and you wouldn’t be too far off the mark.
The National Oceanic and Atmospheric Administration (NOAA) says that many scientists believe the increase in coral diseases and deaths is related to deteriorating water quality associated with human-made pollutants and increased sea surface temperatures.
These factors may allow for the proliferation and colonization of microbes. However, it must be noted that the exact causes of coral diseases remain elusive and actually may be due to multiple factors.
In the above image, courtesy of the USGS, Black-band disease is one of the diseases causing coral mortality in the Florida Keys and the Caribbean. Live coral tissue is light brown, the black line is the disease lesion, and white area is the dead coral skeleton.
The Mote Marine Center for Coral Reef Research and Restoration is located in the Florida Keys. The staff has been working for five years now, raising corals from embryos into adult colonies, then planting them on Florida’s reefs. Mote lab’s science director Erinn Muller calls such this work in progress “our beacon of hope.”
Muller talked to National Public Radio about the strange coral disease, “When they’re affected by this, the tissue sloughs off the skeleton,” she says. “And we see that once a coral is infected, it usually kills the entire coral, sometimes within weeks. And it doesn’t seem to stop.”
Looking for a cure
Scientists have been analyzing DNA to try and identify the pathogens, while others have been looking for a cure. “Anything from… looking at chlorine-laced epoxy as an antiseptic, and even looking at how antibiotics interact with the disease,” Muller says. “Because if it is bacterial, then antibiotics would be a way to stop it.”
While the pathologies or mechanisms by which many diseases act upon the coral polyp are not well known, the effects that these diseases have on corals has been well documented. Black-band disease, discolored spots, red-band disease, and yellow-blotch/band disease appear as discolored bands, spots or lesions on the surface of the coral.
As these bands expand over the coral surface, they consume the living tissue, leaving behind a stark white skeleton. The limestone skeleton is a perfect breeding ground for pathogens, algae and encrusting invertebrates. to set up housekeeping and multiply.
When Director Muller mentioned some scientists were looking at possibly treating the diseased coral colonies with some sort of antibiotic, this writer remembered reading an article written in March by Digital Journal’s Dr, Tim Sandle.
The article outlined a recent study that found that surfers and body-boarders harbor higher levels of potentially dangerous antibiotic-resistant bacteria in their guts compared with non-surfers. The researchers attributed this to the fact that this group of water-sport lovers are more apt to swallow ocean water.
The research team found that body-boarders and surfers had triple the rate of Escherichia coli bacteria; organisms that were resistant to the antibiotic cefotaxime (a class of a β-lactam antibiotic). Cefotaxime is commonly used to treat joint infections, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, sepsis, gonorrhea, and cellulitis. The drug is given either by injection into a vein or muscle.
The paper got this writer to thinking that perhaps scientists may be on the right track in looking for a pathogen, and E. coli is frequently found in runoff from coastal waters, among other nasty things, like fertilizers and raw sewage. Let’s just hope FDEP comes up with some answers.
