🪸 Why Coral Reefs Are Important: What They Give Us

Ask why coral reefs matter and the first answer is usually that they are beautiful. They are, but beauty is the least of it. A reef is a fish nursery, a living breakwater, a sand factory, a tourism economy and, more often than people expect, a source of medicine.

Here is a true hook: one of the leukemia drugs doctors still rely on traces back to a Caribbean sponge that chemists studied in the 1950s. This post covers what reefs actually give us, with the evidence behind each claim. The other side of the story, what happens when reefs are lost, is in our post on what happens if coral reefs disappear.

At a Glance

• Biodiversity: reefs cover less than 1% of the ocean floor but support about 25% of marine species, according to NOAA.
• Food: hundreds of millions of people, mostly in tropical coastal communities, rely on reef fisheries for food and income.
• Coastal protection: a healthy reef absorbs on average about 97% of incoming wave energy, most of it at the reef crest.
• Tourism: reef tourism is worth about US$36 billion a year worldwide.
• Medicine: compounds from Caribbean reef animals led to approved treatments for leukemia and soft-tissue sarcoma.

A Home for a Quarter of Ocean Life

Reefs are crowded because they are complicated. Every coral head, ledge, crack and cave is a different place to live, and the structure stacks those places on top of each other. Small fish hide in gaps a predator cannot enter, lobsters and moray eels take the crevices, cleaner shrimp set up stations, and night feeders sleep in caves by day. Take away the structure and you take away the addresses. Our post on how coral reefs are built explains how that architecture forms over thousands of years.

Reefs also work as nurseries. Many fish arrive on the reef as tiny larvae, and nearby seagrass beds and mangroves trade juveniles with the reef as they grow. Grazers keep the system running: parrotfish scrape algae off the rock, which leaves bare space where young corals can settle.

Food and Fisheries

For people along tropical coasts, the reef is a pantry. Snapper, grouper, grunts, lobster, conch and octopus are all reef animals, and in many countries reef fishing is an everyday source of protein and income for small-boat fishers. Estimates of how many people depend on reefs vary, but they run into the hundreds of millions.

That catch only lasts if the reef stays healthy and fishing stays within limits. The Dominican Republic has seasonal closures for lobster and conch and protects parrotfish because of their role in keeping algae off the coral.

A Natural Breakwater

This is the benefit most beach visitors never think about. A review of 27 studies published in Nature Communications in 2014 found that coral reefs reduce wave energy by an average of 97%, and that the reef crest alone, the shallow ridge where waves break, removes about 86% (Ferrario et al. 2014). That means calmer lagoons, less beach erosion and less storm damage on shore.

Reefs also feed the beach itself. Much of the white sand on Caribbean beaches is ground-up skeleton from corals, shells and limestone-building algae, with parrotfish doing a large share of the grinding. A healthy reef keeps both the wave barrier and the sand supply working for the hotels, roads and homes behind the beach.

Tourism and Local Jobs

Reef tourism is worth about US$36 billion a year worldwide, according to a 2017 study in Marine Policy that mapped it across more than 100 countries and territories (Spalding et al. 2017). That figure covers both on-reef spending, such as diving, snorkeling and glass-bottom boats, and beach holidays that depend on the calm, clear water a reef creates.

In a place like Punta Cana, that money pays boat captains, guides, instructors, hotel staff and restaurant workers. It also gives the reef a value that people beyond the fishing community can see, which is part of why hotels and dive centers in Bayahibe help fund coral restoration there.

Medicines from the Reef

Reef animals that cannot swim away defend themselves with chemistry, and some of those chemicals turned out to be useful to us. In the 1950s, chemists studying the Caribbean sponge now called Tectitethya crypta found unusual nucleosides that inspired a new family of drugs, including cytarabine, still a standard leukemia treatment, and the antiviral vidarabine. A compound from the Caribbean sea squirt Ecteinascidia turbinata became trabectedin, approved in Europe in 2007 and in the United States in 2015 for certain soft-tissue sarcomas.

Keep the bigger claims in proportion. Reefs are a promising source of new medicines, but only a handful of marine-derived drugs have reached the market so far. You can meet the sponges on our own dives in reef sponges of Punta Cana.

What It Means in Punta Cana

Punta Cana's coast is lined by reef, and the beaches behind it depend on it for calm water and sand. Every guest who snorkels a lagoon or dives a site like Park Reef, at 12 m (40 ft), with its turtles, lobster and squid, is enjoying something the reef provides. Local groups such as Fundación Grupo Puntacana and, in Bayahibe, FUNDEMAR run coral nurseries to help reefs recover; read about their work in coral restoration in the Dominican Republic. 🐢

What You Can Do

• Keep off the reef. Do not touch, stand on or kick coral; good buoyancy protects the structure everything else depends on.
• Eat seafood with care. Never order parrotfish, skip lobster during the closed season, and say yes to lionfish when it is on the menu.
• Leave reef souvenirs alone. Never buy coral, shells taken from living animals or turtle-shell products.
• Cover up in the water. A rash guard and mineral sunscreen mean less product washing onto shallow reefs.
• Learn before you dive. Divers who understand the reef are the ones who protect it.

Frequently Asked Questions

Why are coral reefs called the rainforests of the sea?

Because, like rainforests, they pack an extraordinary number of species into a small area. Reefs cover less than 1% of the ocean floor but support about a quarter of all marine species.

How do coral reefs protect the coast?

The reef crest breaks waves before they reach shore. On average, reefs remove about 97% of wave energy, which reduces erosion and storm damage.

Do coral reefs matter to people who never dive?

Yes. They support fisheries, protect coastal homes and roads, supply beach sand and drive tourism jobs, and some reef compounds became medicines.

Do coral reefs produce the oxygen we breathe?

Not in any meaningful amount. The algae in coral tissue photosynthesize, but a reef uses most of that oxygen itself. Most of the ocean's oxygen comes from plankton in the open sea.

The best way to see why reefs matter is to look at one up close. Our Discover Scuba Diving experience takes beginners to shallow reefs no deeper than 6 m (20 ft), with no certification needed.