Reefs

Reefs are divided into three types: atoll, fringing, and barrier. An atoll can be formed around the crater of a submerged volcano. The polyps begin building their colonies on the round edge of the crater, forming a circular coral island with a lagoon in the center. Thousands of atolls occupy the world’s tropical waters. Only four are in the Caribbean Sea; three of those are in Belize’s waters - Glover’s Reef [1], Turneffe Islands [2], and Lighthouse Reef [3].

A fringing reef is coral living on a shallow shelf that extends outward from shore into the sea. A barrier reef runs parallel to the coast, with water separating it from the land. Sometimes it’s actually a series of reefs with channels of water in between. This is the case with some of the larger barrier reefs in the Pacific and Indian Oceans.

The Belize Barrier Reef is part of the greater Mesoamerican Barrier Reef, which extends from Mexico’s Isla Mujeres [4] to the Bay Islands of Honduras [5]. The Belizean portion of the reef begins at Bacalar Chico [6] in the north and ends with the Sapodilla Cayes in the south. This 180-mile-long reef is the longest reef in the Western and Northern Hemispheres.

Coral

Coral is a unique limestone formation that grows in innumerable shapes, such as delicate lace, trees with reaching branches, pleated mushrooms, stovepipes, petaled flowers, fans, domes, heads of cabbage, and stalks of broccoli. Corals are formed by millions of tiny carnivorous polyps that feed on minute organisms and live in large colonies of individual species. Coral polyps have cylinder-shaped bodies, generally less than half an inch long. One end is attached to a hard surface (the bottom of the sea, the rim of a submerged volcano, or the reef itself). The mouth at the other end is encircled with tiny tentacles that capture the polyp’s minute prey with a deadly sting.

At night, coral reefs really come to life as polyps emerge to feed. Related to the jellyfish and sea anemone, polyps need sunlight and clear saltwater not colder than 70°F to survive. Symbiotic algal cells, called zooxanthellae, live within coral tissues and provide the polyps with much of their energy requirements and coloration.

How a Reef Grows

The polyps of reef building corals deposit calcium carbonate around themselves to form a cup-like skeleton or corallite. As these small creatures continue to reproduce and die, their sturdy skeletons accumulate. Over eons, broken bits of coral, animal waste, and granules of soil contribute to the strong foundation for a reef that will slowly rise toward the surface. In a healthy environment, it can grow 1–2inches a year.

Protecting the Reefs

Belize’s reefs are being impacted by overfishing, coastal development, sewage and sedimentation, coral bleaching, and inappropriate and uninformed marine tourism practices, according to Rich Wilson, Mesoamerica Program Manager of the Coral Reef Alliance, a nonprofit organization dedicated to protecting coral reefs around the world. It has been proven that the most effective way to protect reefs is through well-managed protected areas marine areas. In this sense, says Wilson, “Belize is ahead of the curve. They also have a well-established national tour guide training program, which you don’t find in many places around the world.”

When I asked top Belizean naturalist Dave Vernon about the number one way people can be responsible tourists, his immediate response was, “Leave the fins at home!” Beginning snorkelers, he explained, panic when they come up to clear their masks, automatically standing on the coral or kicking it with their fins. “Coral grows one to one-and-a-half inches a year,” he says, and when somebody starts kicking his fins, “you see hundreds of years of coral growth wiped out in seconds.”

Do your part by following simple guidelines on reef etiquette [7].