Year of the Reef

New evidence reveals Bonaire coral reefs not as pristine as widely believed

Research Highlights, April 2008

Bonaire's coral reefs widely considered to be in pristine condition are a popular tourist destination and regarded as one of the jewels of the Caribbean. Preliminary findings from a new science survey have indicated, however, that all is not as perfect as widely believed.

To more fully investigate their health, the National Oceanic and Atmospheric Administration sponsored a January expedition to Bonaire that included scientists from Scripps Institution of Oceanography at UC San Diego, the Virginia Institute of Marine Science at the College of William & Mary, and the University of Delaware. The researchers employed a variety of surveying techniques, including several underwater robots and a monitoring array developed at Scripps's Marine Physical Laboratory. Such vehicles allowed the researchers to probe the "Twilight Zone," little-known areas at 65 to 150 meters (213 to 492 feet) that are normally beyond the standard range of scuba diving.

Scripps researchers and expedition co-leaders James Leichter and Dale Stokes studied oceanographic conditions around Bonaire, which is part of the Netherlands Antilles, deployed various current meters and unique temperature and pressure-sensing arrays, as well as surveyed juvenile corals, sea bottom algae, and fish. The surveys produced the most detailed information yet available for assessing the overall health of Bonaire's reefs

The expedition was part of a series of events that kicked off the International Year of the Reef 2008, a global campaign intended to raise awareness of the value and importance of coral reefs, which are threatened in several locations around the world.

"Our findings are interesting, and also distinctly concerning," said Leichter. "Despite the perception and promotion of Bonaire as a site of 'pristine' reefs within the Caribbean, our preliminary analysis shows extensive areas of coral disease and mortality. The pace of development on Bonaire has increased dramatically in the past five to 10 years and issues of runoff from land and non-point sources of pollution appear to be quite critical."

Yet despite his concern, Leichter witnessed signs of resiliency. Populations of important grazing fishes are large and the researchers documented numerous small colonies of Acropora palmate, Acropora cervicornis, and Acropora prolifera, coral species key to building back a healthy reef framework.

"We need to understand the physical parameters of the reefs as well," added Stokes. "Using new instruments developed at Scripps, we can rapidly deploy sensors over multiple reef locations and collect fine-scale data never before seen. This information will aid in the analysis of the changing reef ecology and help the island mitigate its development."

—Mario C. Aguilera