Most people have a pretty good understanding of what coral reefs are. We see pictures of brightly colored reefs in tropical waters, most notably the Great Barrier Reef. We also know they serve as a habitat for fish and many other marine species. But what exactly are corals? Corals are marine animals in the Cnidaria phylum. They are made up of identical polyps that form into one larger colony. Each polyp has a stomach with an opening for a mouth, which corals can consume small animals. But most corals obtain energy from zooxanthellae, which live in symbiosis with. The corals provide a protective environment, and the zooxanthellae perform photosynthesis and provide energy to the coral. The zooxanthellae are also what gives the coral its bright colors.

There are three types of corals: hard corals, soft corals, and deep-sea corals. Hard corals are probably the type you are most familiar with. They are the backbone of the coral reef ecosystems and are found in all the world’s oceans. Their skeletons are made out of hard calcium carbonate material. Soft corals don’t have those stony skeletons; instead, they are bendable. They typically live in shallow waters, and their shapes are very dependent on the depths of their habitat. One example of soft corals is gorgonians, or sea fans. Lastly, deep-sea corals live far down in frigid waters where there is no sunlight. These corals don’t have zooxanthellae, but they are able to survive by trapping tiny organisms to eat. Some species of deep-sea corals have been growing for around 40,000 years!

Aside from being a remarkable species, corals are one of the most important organisms on the planet. They are extremely biodiverse habitats, supporting possibly millions of species of organisms. 25% of the ocean’s fish species are reliant on coral reefs. Also, chemical compounds from corals are used in some of our most important medicines, including for cancer, AIDS, arthritis, bacterial infections, and viruses. And they support commercial and subsistence fisheries, as well as bringing in tourism to different areas. They serve as a buffer for shorelines from 97% of the energy from currents, waves, and storms, preventing death, property damage, and erosion. They are estimated to directly support about 500 million people around the world.

However, coral reefs are under threat due to overfishing, pollution, and global warming. When the conditions of the environment change, the corals become stressed and expel the zooxanthellae from their tissues. This is why when corals get bleached, they lose their color. When this happens for a period of time, the coral ends up dying. These environmental changes can be alterations in temperature, pH, and salinity outside their normal range, and pollutants.

Currently, some action is being taken to protect coral reefs. The EPA has some initiatives, such as the Clean Water Act, which increases water quality in coral reef areas, and they have worked in the monitoring of reef health. In addition, NOAA’s Coral Reef Conservation Program and Damage Assessment, Remediation, and Restoration Program attempts to restore damaged reefs and implement conservation projects. One method of restoration is coral nurseries, in which coral gametes are harvested and then planted. This way, coral can be grown in safe lab environments where scientists and researchers monitor them. Marine Protected Areas are another popular way to help corals because they prevent damaging activities. However, only 27% of corals live in these areas, and only 15% of these areas are deemed effective.

So, the most essential way to protect coral reefs is to reduce global warming. We must stop burning fossil fuels at the rate we are now and significantly decrease the amount of emissions we are putting into the atmosphere. This means limiting consumption, disposing of trash properly, saving energy, wasting less, and much more (found in the other articles on this site.) But much more than individual people, governments, and corporations are causing these problems, and we must work together as a society to stop them.