Located between North and South America and bounded to the west by the nations of Central America, the Caribbean is the world’s second-largest sea and is home to 116 million people. Its 1.2 million square miles take in a wide variety of marine ecosystems. The water and the coastline of the Caribbean are its major tourist attractions, with diving and water sports among the most popular activities for visitors.


The Caribbean area is home to 7 percent of the world’s coral reefs. The Mesoamerican Barrier Reef is the largest coral reef in the western hemisphere and stretches from the coast of Mexico to the bays of Honduras and, according to the Coral Reef Alliance, contains “some of the richest biodiversity in the wider Caribbean.” The corals grow slowly but over time accumulate into very large structures supporting a diverse ecosystem; it’s common for Caribbean reefs to support several hundred species each of invertebrates, snails and fish alongside up to 60 different species of corals. The reefs are threatened by climate change, which tends to make water warmer and more acidic. Tourist activities are also a threat, so if you’re planning a diving trip, ask what precautions your operator takes to protect the fragile corals.


Seagrass meadows are an important feature of the Caribbean and play a role in the movement of sand around the region. Turtle grass, shoal grass and manatee grass are the most common species you’re likely to encounter. Like grass on land, the sea grass are flowering plants and establish themselves in the sandy sea bed. Their roots help to hold the sand in place, meaning they play an important role in preventing beach erosion. The plants’ leaves provide a home for young lobsters and conch as well as other tiny marine creatures. Unfortunately, sea grasses are vulnerable to pollution and the World Wildlife Fund believes that numerous meadows have been destroyed by pollution from oil drilling in Venezuela, Trinidad and Tobago and Barbados.


Although algae are the smallest plants in the coral reef ecosystem, they play a vital role in stabilizing the structure. The two main types found in the Caribbean are coralline and calcareous algae. Coralline algae spread out in a fine layer across the surface of the coral, trapping particles of sand and helping to firm up the coral. Calcareous algae grow upwards from the coral’s surface. When they die, their remains disintegrate to form sand. The Caribbean Conservation Association estimates that up to 50 percent of the sand on some Caribbean beaches originates with these tiny plants.


Mangroves are relatively common in the Caribbean. They are made up of evergreen shrubs and trees that can tolerate the salty ocean water. The state of Florida alone has more than half a million acres of mangroves, in which rhizophora, avicennia and laguncalaria are commonly found species. Each show adaptations, such as rhizophora’s combination of stilt and drop roots, that help it survive in a harsh environment. Mangroves provide a habitat for many seabirds, while their moist roots shelter fish, shrimp, sea snails and clams. Changes in sea level can damage mangroves, but research by a team from the Smithsonian Institution and the U.S. Geological Survey suggests the mangroves are able to tolerate changes in the water level by accumulating organic matter around their roots.

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