Coral reefs are the rainforests of the ocean. Vivid colours greet divers as an entire realm of fish and aquatic life go about their day in and around these spectacular structures. Full ecosystems of submarine animals living in harmony with the coral reef. Hiding within its caves and recesses or feeding on the plants that flourish and seem to wave to you, beckoning you deeper into this other dimension of experience. But how do coral reefs work? What do they even do? Well, grab your imaginary scuba tank and come along for a ride.
Coral reefs are underwater structures made from calcium carbonate, the hard skeleton secreted by corals, which are marine invertebrates – little buggers living in colonies upon the reefs made out of the stuff they create. So of course the reef itself is a living breathing organism, like the rainforest or the planet herself. It’s one of the most diverse ecosystems on the planet, home to tens of thousands of marine species. In fact, a full 25% of all marine species live at least part of their lives in the coral reefs – an impressive number considering reefs account for only 0.1% of the ocean’s surface area. As you can imagine, these magnificent structures are incredibly vital to the health of the entire ocean.
Some reefs in the Caribbean are home to over 50 species of stony coral and as many species of octocoral. Living off said coral are several species of sea turtles, over 500 species of fish, and over 1,700 species of mollusks and sponges, all in bright brilliant colours. There’s a good reason for them to be so prevalent in the tropical waters too and that is the increased amount of sunlight through warm and clear waters it the prime breeding ground for an abundance of coral and reefs. They’re remarkably self-sustainable as well, as even when there are few nutrients in the surrounding waters they still flourish and thrive.
There are three main types of reefs in the world: Fringing Reef (directly attached to the shore); Barrier Reef (separated from land by a deep channel or lagoon); and Atoll Reef (circular reef more or less completely surrounding a lagoon). Cays are another form of reef that are found in Caribbean, small sandy islands that are formed on the surface of coral reefs, resulting in an habitable area stabilized by plants.
There are also three major zones within a reef: the Back Reef (aka the reef lagoon less affected by wave action); the Reef Crest (the Outer/Fore Reef (where it slopes into the drop-off zone). There are other zones and the topography of the reef is of course in constant flux as it is again an organic being that is always growing and changing in shape from year to year.
Not only do coral reefs provide home to an abundance of life, they also protect the shoreline from dangerous storms, as well as stimulate the local economies with fishing and tourism. Some 500 million people around the world depend on coral reefs. Speaking about money, as much as some may say it’s impossible to put a price tag on something so naturally beautiful but nonetheless, the annual global economic value of all the reefs is estimated at somewhere between US$ 30 and 375 billion. Due to their relative fragility and current status as a commodity in some circles, reefs are threatened by several factors. Climate change, oceanic acidification, blast fishing, pollution and overuse of reef resources are all directly contributing to the degradation of these amazing ecosystems. To emphasize this point: coral reefs are dying around the world. It’s estimated that 10% of the reefs are already dead and 60% are currently at risk due to destructive human-related activities.
Marine protected areas (MPAs) are being increasingly established to protected these reefs by restricting damaging actions, much like a national park or wildlife refuge. These designations often do not help, however and other titles (like biosphere reserve, national monument, or world heritage site) are put in place in attempts to develop a sort of force field around the reef.
If you’ve never experienced the rainforests of the sea first hand, you’re missing out on the abundance and beauty that the earth has to offer. Next time you’re in the Caribbean make sure you visit one. Go pay your respects to the planet. Tell her thanks for doing her thing.