While diving and snorkeling are two of the most popular activities for tourists vacationing in the Dominican Republic , it might be good to get a handle on some basic knowledge before paddling out to see the splendid colors, to make sure to preserve the delicate ecosystem.
There are three types of coral reefs: the fringe, the barrier, and the atoll. The fringe is a great place for beginners, since it is close to (and connected to) the mainland and therefore tends to be in shallower waters. It has a good variety of coral species.
Just past the fringe reef you’ll come to the barrier reef, where the sea life is dialed up a notch from the fringe reef. The type of barrier reef commonly found here is the bank/barrier reef, which is smaller than a barrier reef found in the Pacific Ocean. You’ll need transportation to get out to a bank/barrier reef as there are hundreds of meters between it and the shore.
Charles Darwin reasoned that an atoll came to be from a fringing coral reef surrounding a volcanic island that eventually grew upward as the island began to sink, turning the fringe reef into a barrier reef. In time, the old volcano fell below the surface of the ocean and the barrier reef remained, thereby graduating to atoll status. This type of reef is rare in the Caribbean and the closest one to the Dominican Republic  is in Belize.
There are two types of coral: hard and soft. While it would seem that the hard corals are the skeleton of the reef and the soft corals merely decorate it, that is not the case. In fact, the creation of a coral reef is very much a team effort. While the hard corals do indeed form the skeletal portion, many types of algae act as the mortar to help bind and solidify the frame. Then crustaceans, mollusks, sponges, urchins, and soft corals all come in to anchor the reef. And just as in a community, there are the vandals. Let’s cut the snails, crabs, and parrotfish a little more slack, though; they are, after all, surviving off of the reef.
Scuba diving and snorkeling are vastly popular activities, but so much “flipper traffic” has done tremendous damage to the reefs. Make sure that you follow the simple and very important rules while visiting their habitat: Don’t stand on it or touch it. Be careful with your fins; while kicking you can easily accidentally do a lot of damage. And above all, don’t take a piece as a memento, even though it is very tempting. Many of the coral reefs have suffered as a result of the tourism industry, which includes individuals who harvest the reefs to make jewelry to sell on the beaches and in the markets.