Belize is home to the second largest coral reef in the world (outside of Australia's Great Barrier Reef). Fifty feet below the Caribbean's sun-dappled surface, schools of navy blue tangs drift like smoke, their languid progress mirrored by the gentle waving of purple sea fans and yellow tube sponges. A hawksbill turtle chugs along a ledge studded with elkhorn and brain coral, oblivious to the gaggle of adoring scuba divers trailing in its wake.
From this comparatively pristine vantage point, it's easy to see why naturalist Charles Darwin declared this necklace of mangroves, seagrass and submerged coral, stretching more than 150 miles off the Belize coast, "the most remarkable reef in the West Indies."
Coral reefs make up less than 1% of the marine environment, but they are home to a dazzling diversity of life, and they often are tourist attractions. Here are some tips for minimizing the impact on fragile reefs in the face of growing threats:
Look, don't touch. Since even slight contact can remove a coral's protective mucous layer and make it more susceptible to disease, keep fins, hands and gear off the reef. Stay off the bottom because disturbed sediments can smother corals.
Watch the sunscreen. According to a new study, up to 6,000 metric tons of sunscreen washes off ocean swimmers worldwide each year, and ingredients found in many sunscreens can contribute to coral bleaching. Advice from diver publication Undercurrent.org: Use screens that contain titanium dioxide and zinc oxide, which reflect instead of absorb ultraviolet radiation.
Don't feed fish. Doing so can alter and encourage more aggressive behavior. Never chase, harass or try to ride marine life.
Of all wetlands, coral reefs are the most diverse, being home to more species than any other marine ecosystem. Only tropical rain forests rank higher on the biodiversity scale. This huge diversity is a result of careful partitioning of the reef by all its inhabitants - some use the reef at different times of day (many reef species are nocturnal), others share it by eating different food. Although reef diversity is much lower in the Caribbean than in the Indo-Pacific (a result of the geological history of the region), over 1,000 species may nevertheless occur on a single reef. Belize has a particularly high species diversity for the region, with about 65 coral species and over 300 fish species, compared with just over 70 coral species and about 520 fish species in the Caribbean as a whole.