NEWS YORK TIMES: Mysterious New Diseases Devastate Coral Reefs

Griffis, Roger B Roger.B.Griffis at
Wed Aug 20 15:12:32 EDT 1997


August 19, 1997

NEWS YORK TIMES: Mysterious New Diseases Devastate Coral Reefs

 Mysterious New Diseases Devastate Coral Reefs


 [T] wo coral researchers were asked to examine the
 reefs off the island of Bonaire in January after
 divers noticed strange white lesions on the star and
 brain corals in waters considered to be among the most
 pristine in the Caribbean.

 Under water, the researchers, Dr. Thomas J. Goreau and
 James Cervino, found something they had never seen
 before, huge patches of dead coral, bright white where
 the skeleton had been exposed after tissue had died;
 the skeleton itself was crumbling away.

 "We were quite horrified," said Goreau, who along with
 Cervino is with the Global Coral Reef Alliance, a
 nonprofit organization for the protection and
 management of reefs. "It looks like someone poured acid
 over the top of the coral. The skeleton itself is
 dissolved. I've been looking at reefs in the Caribbean
 probably longer than anyone else alive and I'd never
 seen it before. It's attacking at a speed and with a
 level of damage that is unprecedented."

 The researchers say rapid wasting disease, so named
 because it can spread several inches across a coral
 head in a single day, is all over the reefs of Bonaire
 and since January has been spotted in Mexico, Aruba,
 Curacao, Trinidad, Tobago, Grenada and St. John's in
 the Virgin Islands, an area spanning 2,000 miles.

 But more alarming than the spread of rapid wasting
 disease is the fact that it is only one among many
 mysterious new diseases that have been discovered
 attacking corals around the world. In what they are
 describing as an epidemic, researchers say that in the
 last few years corals, some centuries old, from the
 Florida Keys through the Caribbean to places as distant
 as the Philippines, are quickly succumbing to diseases
 never before seen.

 Unlike the many other stresses on corals with which
 scientists and the public have become quite familiar,
 including bleaching, sedimentation, pollution and
 rising sea temperatures, the rash of new diseases has
 taken researchers by surprise.

 "We're all stunned at the rapidity with which these new
 diseases are occurring," said Dr. James W. Porter, a
 marine ecologist at the University of Georgia in Athens
 who last year discovered a new disease known as white
 pox. "The problems are occurring at all depths, and the
 numbers of species affected is increasing as well as
 the number of individuals. It's definitely on the

 Dr. Drew Harvell, an ecologist at Cornell University in
 Ithaca, N.Y., whose graduate student in the
 Philippines, Laurie Raymundo, recently found a disease
 in all her study areas that they have been unable to
 identify, said: "There seem to be more diseases than
 anyone can keep up with. There are a lot of new names
 and attempts to correlate symptoms with names and with
 causes, but so far, heaven only knows what's going on."

 Fewer than a dozen of the new diseases even have names
 and those with names are still in the process of being
 documented, leaving biologists to rely on word of mouth
 to keep the growing number of maladies straight. As a
 result, simply recognizing whether a coral is healthy
 or sick can be extremely difficult, even for practiced

 Last month at a meeting of the Association of Marine
 Laboratories of the Caribbean held in San Jose, Costa
 Rica, Goreau spoke at a special daylong session devoted
 to coral diseases, one of the first chances researchers
 have had to exchange information on the problem.

 "I showed about 50 pictures" of coral diseases, said
 Goreau, "but it wasn't nearly enough. Most people are
 saying, 'We're seeing all of these but we just didn't
 know it before.' " For example, rapid wasting disease,
 which exposes a white, crumbling skeleton, is easily
 and often mistaken for anchor damage or parrotfish

 Scientists say they have no idea why diseases are
 exploding on corals now. Some speculate that multiple
 stresses, like bleaching, sedimentation and pollution,
 have pushed corals to the breaking point so that they
 are now unable to fend off diseases that they have
 fought off in the past. With the scant and scattered
 information researchers have so far on where the
 diseases are, there seems to be little sense to their
 spread, with some pristine reefs succumbing to disease
 while other much more polluted reefs remain healthy.

 "It's a baffling situation," Goreau said. "Most
 diseases are new. They don't correlate with each other
 or any known environmental stress. In Bonaire, rapid
 wasting disease is having a devastating impact, yet the
 reefs there are so clean."

 Others have suggested that perhaps erosion and the
 dumping of sewage and other wastes into the sea has
 brought a whole host of new pathogens in contact with
 corals and some are taking hold. While the notion that
 terrestrial pathogens might begin underwater attacks on
 corals might seem far-fetched, researchers say there is
 evidence that at least one of the newly emerging
 diseases, sea fan disease, is caused by an organism
 that invaded from land.

 Discovered just four years ago, this disease of soft
 corals is now widespread in the Caribbean and has been
 shown to be caused by a highly opportunistic fungus
 called Aspergillus. Adhering to sediment that has
 washed into the sea, the fungi begin to grow when they
 encounter a sea fan. Researchers say they are sure it
 is a fungus brought from land because it cannot
 complete its life cycle in the ocean. "It's a
 terrestrial organism that has crossed the land-sea
 barrier," Harvell said.

 Researchers suspect a fungus is behind rapid wasting
 disease and various bacteria are implicated in other
 new coral diseases. But for the most part, definite
 causes remain unknown.

 Scientists say even corals in aquariums, like the
 Waikiki Aquarium in Honolulu and the National Aquarium
 in Baltimore, are being hit.

 In order to make identification of diseases more
 straightforward, some researchers are trying to develop
 molecular tests for coral diseases. Dr. Harvell and
 colleagues are working on a test for sea fan disease,
 trying to develop a sort of DNA fingerprint of the
 pathogen that would allow researchers who suspect that
 a coral has the disease to test DNA from the infected
 area and find out definitively if the fungus that
 causes sea fan disease is present.

 As scientists struggle to identify illnesses, cures for
 sick corals appear to be a long way off. Some have
 suggested simply applying antibiotics to the reefs.
 Scientists warn, however, of the unknown hazards of
 dispensing into the seas a drug that can destroy useful
 bacteria as easily as harmful bacteria and that may not
 do any good if the pathogens that are involved turn out
 not to be bacteria at all.

 Researchers have had the most luck treating black band
 disease by vacuuming off the diseased band of tissue
 that gives the illness its name. But the work is
 extremely time-consuming, and that type of approach is
 practically impossible for the most quickly spreading
 and worrisome diseases.

 "I couldn't imagine going out and treating a disease
 like that," said Dr. Laurie Richardson, an aquatic
 microbiologist at Florida International University in
 Miami who studies white plague type 2, a disease that
 swept through the upper Florida keys in 1995. In just
 four months, it spread more than 100 miles, jumping
 from one to 17 species of corals.

 But while scientists lament having to stand back and
 watch these diseases ravage coral populations, they
 note that sometimes no treatment can be the best cure.
 Once a disease is allowed to rage through an area, any
 healthy, resistant individuals left behind can begin to
 rebuild a tougher population.

 Other inhabitants of reefs are beginning to come down
 with diseases as well. Dr. Goreau said sponges,
 coralline algae and sea urchins were also succumbing to
 new illnesses, further threatening the health of reef

 Coral reef biologists say they are further frustrated
 by a lack of money for such quickly unfolding research.

 "We've tried getting money from the National Science
 Foundation," said Dr. Goreau. "You send a proposal and
 wait a year or two for the review. You can't deal with
 this kind of emergency science that way."

 Researchers are now scrambling to document the extent
 of these emerging diseases, the numbers and types of
 corals attacked, and the level of virulence of these
 pathogens. But with such basic information still
 largely unknown, they are left with a mixture of dread
 and hope.

 Cervino, for one, is soliciting reports of new
 outbreaks of coral diseases from observers around the
 world. His e-mail address is:

 "There are places where there are 200- and 300-year-old
 coral colonies being devastated," said Dr. Esther
 Peters, senior scientist at Tetra Tech, an
 environmental consulting company in Fairfax, Va., "and
 there are places where the corals are fine. I'm afraid
 it is getting worse, but all is not lost yet."

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