KIHO KIM/CORNELL UNIV.

As part of the Environmental Protection Agency's Coral Reef Monitoring Program, Porter and colleagues in 1995 set up 160 stations extending the length of the Florida Keys. Last year, they found several diseases in a small area (Science, 20 December 1996, p. 2017). Now it appears that there are more diseases than ever, and that they are widespread throughout the Keys.

Between 1996 and 1997, Porter related, the number of stations where sick corals were observed rose from 25 to 94. Of 44 species monitored, the number afflicted rose from nine to 28. And of 13 diseases, three are "entirely new to science." One causes brain coral to swell up; in another, "tissue is mowed off the skeleton in a brilliant red line"; and another is killing the tops of coral ridges. That's on top of white pox, black band, and other alarmingly named afflictions.

Scientists still don't know the causes of most of these diseases. A theory is that runoff from sewage and pesticides as well as light deprivation from turbidity are stressing corals, making them more susceptible to existing pathogens. But at least one non-marine organism has been implicated: Aspergillus, a soil fungus that afflicts soft corals known as sea fans. Garriet Smith, a marine microbial ecologist at the University of South Carolina, Aiken, says fungus-bearing sand may be blowing in from the Sahara.

Lauri MacLaughlin, a resource management specialist at the Lower Keys office of the Florida Keys National Marine Sanctuary, says officials are concerned about the apparent increase in disease but cautious about the implications--"We're so unsure right now what's going on. We're just trying to get a handle on it."