Why are Coral Reefs Important to the Ecosystem?

Coral reefs are essential pieces of a balanced ecosystem, which is kind of a shame since they are among the most endangered individual biomes existing in our world today. These gorgeous undersea cities are home to thousands of individual organisms, including fish, crustaceans, corals, anemones, and microorganisms. It isn’t just the underwater ecosystem, either — coral reefs form a necessary link in the chain of Earth’s ecosphere. But why are coral reefs so important to the ecosystem, anyway?

According to the Coral Reefs Alliance, coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates. These invertebrates are known as coral. Some of them are hermatypic, or “hard” corals that extract calcium carbonate from seawater. This results in a durable exoskeleton that protects the corals’ soft, sac-like bodies. A coral reef isn’t just made of coral, though. 

Coral reefs are diverse marine ecosystems in their own right, teeming with hundreds of species of fish, crustaceans, mollusks, and other invertebrates. Coral reefs can be found all over the world. The largest of all these reefs are found in shallow, tropical, and subtropical waters, and one of the very biggest of those — and the most endangered — is the Great Barrier Reef in Australia, which measures more than 1,500 miles long. 

Coral reefs serve many roles within the marine ecosystem, but they are also important to the way our global ecosystems work as well. Coral reefs protect coastlines from the damaging effects of waves and tropical storms. They provide habitats and shelter for thousands of marine organisms. Coral reefs help with nutrient recycling, assist in carbon and nitrogen-fixing, water filtration, and provide nitrogen and essential nutrients for the diverse array of life that exists within the marine food chain.

This should go without saying at this point, but a lot of animals call coral reefs their home. The degree of biodiversity in the reefs is unmatched anywhere else in the world with the exception of some rainforests. This, in turn, creates a complex food web, that goes from the sharks and dolphins at the top of the food chain to tiny sponges, invertebrates, and plankton at the bottom. 

Eels, octopuses, clams, crabs, and clownfish rely on the reefs for protection. This vast array of creatures creates balance, and that balance eventually finds its way to the surface. It finds its way to our dinner tables and to our restaurants, to our boats and boardrooms. In fact, that marine biodiversity is one of the main things that keeps many seaside cultures going. 

According to the EU Science Hub, baseline data from 2011 indicated that the global demand for seafood destined for human consumption is 143.8 million tons per year. That is a heck of a lot of fish, and that prediction was some nine years ago. Since then, the global population has risen to 7.8 billion people, so that the original number has also risen. 

Fish and other marine life have been a source of food for nearly all of human history. Commercial fisheries, small local fisheries, and individual anglers, all depend on the bounty of the sea. Lobsters, stone crab, snapper, and grouper, all live in and around the reefs. They depend on them for spawning and habitat. But tuna and other pelagic species that dwell in the open water need the reefs as well — albeit indirectly. They live on the baitfish that breed and live in coral reefs. 

Our coastal cities depend on the coral reefs to provide a buffer to wave action and storm surges. The Great Barrier Reef is aptly named because it provides a barrier against the destructive ocean forces that would have otherwise eroded the coastline of the continent. Coral reefs stabilize mangroves and seagrass beds, providing habitats, oxygen, and vegetation for inland species besides humans. In the Florida Keys, where the shore is lined with residential homes and commercial buildings, these reefs are a last line of defense against devastating tropical storms. 

According to Reef Relief, there is a reason that coral reefs don’t really exist in murky or polluted waters. Corals and sponges are often filter feeders, which consume particles from the water that surrounds them. This filtration then enhances the clarity and quality of the ocean’s waters. The problem is, the oceans today are much dirtier than they were when these simple organisms first evolved to perform this essential task. 

The amount of plastic, microplastics, toxins, and chemicals in our oceans is too much for the simple corals to take. They take in these toxins and exhale clean water, but the process corrupts their bodies as surely as it would our own. Without coral to filter the water and clean it up, our beaches and reefs will continue to succumb to pollution. Eventually, no creatures will be able to live in those waters. 

Coral reefs are usually part of national parks, and tourism accounts for a huge chunk of the economy in some places. Hawaii, Australia, Florida, and so many other places rely on their beaches, reefs, and wildlife to draw in visitors and keep themselves afloat. Pollution and coral damage has caused water to become murkier, beaches to become less hospitable, and many marine animals to become endangered. Without these things in place, coastal and island economies will falter — putting human lives and livelihoods at risk. 

Coral reefs are important to the ecosystem because they are the pillars on which marine and coastal ecosystems are built. They keep plants, fish, and animals fed. They clean up our water and protect our coasts. The damage already done to these unique and essential biomes could be a sign of a grim future for everyone.