Concerning Caribbean Coral
by Robert Rattner
The reefs of the Caribbean are relatively young: less than 20,000 years old. During the last glacial period, the waters of the Caribbean cooled, and its ancient corals died. Unprotected, the islands were battered by waves and the shoreline eroded, leaving underwater shelves or banks around them. As the seas warmed, corals returned, and reefs formed at the margins of these shelves—inspiring the name “bank barrier reef.” These reefs are less extensive than barrier reefs, have shallower lagoons, and are found closer to shore.
Being the youngsters of the world’s coral reef clan—Indo-Pacific reefs may be hundreds of thousands or even millions of years old—Caribbean reefs are home to fewer species than some reefs elsewhere. Still, more than 1,000 species can be found on some individual reefs. “The Caribbean is the richest area of species diversity in the Atlantic,” notes Dan Brumbaugh of the American Museum of Natural History.
On land as well, the islands of the Caribbean—though mostly small in size—are home to a host of ecosystems and wildlife. Humid rainforests and arid desert scrub lie beyond the palm-fringed beaches that capture the minds and dollars of winter-bound northerners. The diverse and unique species found there—including an amazing array of land bird species found nowhere else on Earth, and one of the world’s richest assemblages of reptiles and amphibians—prove that not all the islands’ wildlife is found in beach bars.
The onshore and offshore ecosystems of the islands are inextricably entwined, and easily damaged. Growing human populations and the quest for economic development are taking their toll. More people need more food, but many of the shallow lagoons of the bank barrier reefs have already been overfished. As upland forest trees are cut to build new homes, and land is cleared to grow crops, valuable water catchment is lost. In Puerto Rico, just one percent of the island’s historic rainforest is left. Tropical rains wash the newly loose soil, as well as pesticides and fertilizers, into rivers and streams. It all gets carried to the sea, where tides and currents distribute it onto coral reefs and sea grass beds.
Economic growth on many islands is tied to tourism. As ever more vacationers come seeking the sun, new resort hotels rise along the coasts. Their untreated waste often gets pumped into the sea. Boatloads of tourists visit the reefs and sometimes drop anchor, which is like letting a bull loose in a china shop—everything it touches will be destroyed. Throngs of snorkeling tourists bump into coral and kick up sand that settles onto the polyps. Scuba diving now brings considerable revenue to some islands, but a poorly trained diver can do even more damage than a snorkeler.
“The ecosystems are physically small and, therefore, particularly fragile,” observes Rosemarie Gnam, assistant director of the Center for Biodiversity and Conservation at the American Museum of Natural History. “Proper planning and regulation of development is essential, or people will destroy the very thing they have come to enjoy."
Zoogoer 30(4) 2001. Copyright 2001 Friends of the National Zoo. All rights reserved.
