Melanie Mcfield is the Director of the Healthy Reefs for Healthy People Initiative and wrote this stellar article for Destination Belize Magazine, which begins by talking about Glover’s Reef. In the photo below, the three atolls of Belize, clockwise from left, are Turneffe Islands, Lighthouse Reef, Glover’s Reef. Our private island, Long Caye, is located at Glover’s Reef.

The three atolls of Belize

Charles Darwin didn’t actually visit Belize’s reef, but after talking to other naturalists who had, he described it as “the most remarkable reef in the West Indies” in his 1842 book, Coral Reefs of the World. Among his many accomplishments, Darwin is credited with unlocking many of the mysteries of coral reef development, evolution and atoll formation. Atolls in the Pacific Ocean are believed to have formed when volcanic islands sank into the sea, leaving just a rim of growing coral near the surface. Atolls in the Western Caribbean are thought to have a different history. Many scientists believe these circular rims of coral are actually growing to keep pace with rising seas. Belize’s atolls are living, breathing coral reefecosystems—each with a unique history and a unique character.

Glovers Reef, Lighthouse Reef and Turneffe Reef are three of the four such coral structures in the Northwest Caribbean; the fourth is located near Banco Chinchorro in Mexico. The atolls rise deep from the seabed, beyond the more familiar continental shelf demarcated by the barrier reef. They are each constructed on foundations of Pleistocene limestone ridges that lie on submerged tectonic faults running in a Northeast direction.

Glovers Reef is the oldest (~7,500 yrs) with the best circular shape, a well developed coral rim and the deepest inner lagoon (18m deep) containing over eight hundred patch reefs scattered throughout. A few sandy cayes make up a land surface of only 0.2% of its total size of approximately one hundred and sixty square miles. Although it is ‘oceanic’ in character with clean clear waters, Glovers is occasionally affected by large river runoff events from the large Honduran rivers to the south. The entire atoll is a marine reserve and is one of the crown jewels comprising Belize’s World Heritage Site. The islands are all privately owned but Middle Caye was donated to the Wildlife Conservation Society and now serves as the headquarters of the reserve and an active marine research station. Glovers Reef has the largest remaining Nassau grouper spawning aggregation site… (read the full article here).

To learn more about the formation of Glover’s Reef Atoll, visit our website.

Many people who contact us are confused about the difference between an atoll and an island. We own the island Long Caye, which is located at Glover’s Atoll, also called Glover’s Reef. We often hear “I want to visit your island, Glover’s Reef.” But this is incorrect. If you are also unclear as to just what an atoll is, I hope that this will help.

Coral polyp off the coast of belizeAtolls are made of coral. Coral is a tiny animal, usually about 1/4″ long, that lives in huge colonies. The individual coral animal is called a “polyp”. The coral polyp takes minerals out of the sea to make their house. When there are thousands of polyps doing this together, they create a huge, expanding, home. Although different species create different shapes, the coral structure often resembles a big rock with fantastic textures on the surface.

Brain coral off the coast of belizeCorals live in a symbiotic relationship with a plant, an algae called zooxanthellae (“zoh-zan-THELL-ee”). This is a win-win relationship where they each get something out of the deal. Because this plant is so important to the coral, coral thrive near the surface of the ocean, to be nearer to the sun. It’s the plant that needs the sunlight, not the coral animal.

Since corals create their rocky home from scratch, they need somewhere to start. Coral doesn’t float around in the sea, it has to attach somewhere. So any hard surface in a location that is conducive to coral growth will soon be covered with coral.

Many people think that atolls have to be associated with volcanic activity. This is because in the Pacific most of the rock structures that coral is attached to are volcanic in origin. But it doesn’t have to be that way. Even a sunken ship is covered with coral. In the Caribbean, there are only 4 atolls: Banco Chinchorro, Turneffe Islands, Lighthouse Reef, and Glover’s Reef. All but the first are in Belizean waters. Banco Chinchorro is just north of the others in Mexican seas. To view a detailed Belize map that includes the location of all four atolls, visit our website.

The reason these atolls are where they are is due to several underwater ridgelines that formed when the super-continent Pangaea broke up, Pangaea existed about 250 million years ago.

Satellite view of Glovers Reef Atoll and Long Caye off the coast of BelizeWhen it broke into the proto-continents of today, it left several underwater, but shallow ridges just off the coast of present-day Belize and Mexico, a perfect place for coral to attach to. The Belize Barrier Reef formed on two of these ridges, and the atolls of Belize and Mexico formed on two of them also.

Originally actual islands formed where the four atolls are today. But as the continents drifted slowly apart, this region also sank slowly, allowing the coral that was attached to the edges of these islands to continue to grow to stay near the sunlight to benefit the zooxanthellae. So what remained after all the drifting and sinking finished were 4 rings of coral way out in the middle of the ocean.

Islands formed on top of these coral rings. Long Caye is one of them. There are 4 islands at Glover’s Reef, one at Banco Chinchorro, three at Lighthouse Reef, and numerous islands at Turneffe, which never did sink completely.

To read more about Belize atolls, visit our website.