Sick coral
Coral -- the calcifying animal that forms coral reefs -- lives in a symbiosis with algae. Coral provides the housing, and algae uses photosynthesis to put food on the table. This age-
Before and after. This Montastrea annularis is part of a large coral colony in Florida that was entirely bleached.© 1997, Craig Quirolo, REEF RELIEF.
Coral reefs are home to staggering marine diversity -- where fish, plants, and other organisms mingle in a marine equivalent of a tropical rain forest. The phantasmagoria of life makes reefs a magnet for scuba divers.
© 1997, Craig Quirolo, REEF RELIEF.
Yet coral is getting sick. For years, we've known about coral bleaching. This whitening gradually kills coral when warm waters inactivate or kill the algae. "When water temperatures rise 1°C above the average summer high, coral bleaches," says James Porter, a professor of marine science at the University of Georgia. "Ninety-nine point ninety-nine percent of bleaching is due to elevated temperature."
With global temperatures going up, bleaching is making for a bleak picture below the surface.
Now comes a slew of new coral diseases with primitive names like black band, white pox, and white plague. Studies within the past two years have found extensive damage -- "a disturbing new kind of thing that we're unprepared to understand," Porter says.
In the early 1970s, between two and four coral species were getting sick in the Keys; today's casualty toll includes 14 species. "Almost all these diseases are new to science, have never been seen or described before," Porter says. "They could be viral, bacterial, fungal, or protozoan, we simply don't know. Our level of ignorance is quite frightening."
The number of study sites exhibiting disease grew by 446 percent between 1996 and 1998. The good news is that only one was severely damaged.
Clinic for coral
At this point, marine biologists are watching and waiting nervously to see if the recent rapid decline continues. Reefs, after all, are natural breakwaters that prevent shore erosion and house innumerable rare species. If they go, downstream ecological consequences are certain.
"If this continues over the next two years, there will be very serious consequences for the Florida Keys," says Porter.
We hooked oceans of reading in our bibliography.
Porter admits that the wave of illness could reflect natural fluctuations. "Is this a simple aberration, a natural increase of disease? Or is disease more common because of things that humans are doing to the planet?" The latter possibility is likely, Porter says, because coral diseases are worst where development is most common. It's a trend we've seen before: human disturbance, specifically global warming, is suspected of helping cholera's return. Similarly, excess nutrient run-
