Dr. John Bruno, assistant professor of marine sciences at UNC, and colleagues at other U.S. universities, believe they have identified one reason why. Results of field experiments they conducted off Mexico's Yucatan Peninsula suggested that chemical nutrients washed and dumped into the sea can increase the severity of coral diseases.
A report on the findings appears in the December issue of the journal Ecology Letters, which is expected to be posted online Nov. 26. Besides Bruno, authors are Drs. Laura E. Petes of Oregon State University, C. Drew Harvell of Cornell University and Annaliese Hettinger of California State University in Northridge.
"Caribbean coral reefs have declined dramatically over the past 20 years or so as disease epidemics have swept through them," Bruno said. "In less than a year, the two most common species that covered 60 to 70 percent of the bottom were just wiped out, becoming functionally extinct and changing possibly forever the structure of those marine communities. It was analogous to losing all the pine trees in the Carolinas down into Georgia."
Since no one had gone into the field to test the nutrient hypothesis about what was happening, the UNC scientist and his colleagues did just that. They looked specifically at the fungi Aspergillus, which kills elegant gorgonian sea fans through a disease known as aspergillosis and two species of the reef-building corals Montastraea, which yellow band disease can kill.
The researchers placed various concentrations of time-release fertilizer rich in nitrogen and phosphorus in porous bags made from pantyhose and suspended them at sites on reefs some four to
Contact: David Williamson
University of North Carolina at Chapel Hill