GIS to Study Coral Disease Spread

In the last 30 years, more than 90 percent of the reef-building coral responsible for maintaining major marine habitats and providing a natural barrier against hurricanes in the Caribbean has disappeared because of a disease of unknown origin.

Now a University of Florida geographer and his colleagues applied Geographic Information Systems, known as GIS — as well as software previously used to examine human illness — to show where clusters of diseased coral exist. Their findings, published this month in the journal PLoS One, may help scientists derive better hypotheses to determine what contributes to coral disintegration.

“What you’ll find is that spatial techniques have been used relatively little in the coral research community,” said paper co-author Jason Blackburn, a UF professor of geography and member of UF’s Emerging Pathogens Institute. “With these methods, we gain a better understanding of the disease’s distribution across the reef.”

Microbiologists and toxicologists often run laboratory tests on small samples of Acropora species of coral to determine the factors that contribute to white-band disease, known as WBD. It’s visually identified as a white band moving from the base of the coral up, killing the coral tissue as it goes, leaving only the exposed coral skeleton behind.

Laboratory results spur a range of theories of causation — anything from opportunistic pathogens to specific bacterial infections. Other scientists suggest that WBD is not the result of an outside agent, such as bacteria, but rather a stress response from the coral in reaction to changes in the marine environment, such as ocean pollution and rising ocean temperatures due to climate change.

Yet the cause remains unclear. The goal of this current study was to use GIS and spatial analysis to search for patterns in a WBD outbreak that might point to a mode of transmission or cause, Blackburn said.
[more from University of Florida news]