Green Pages

National Treasure

It’s time to appreciate our coral reefs.

By Melissa Heres, Waterfront Assistant, The School for Field Studies

For visitors and residents of the Turks & Caicos Islands, the sea—and particularly the reefs surrounding the islands—serves as a source of food, a protective barrier from storms and waves, and a symbol of natural beauty. Sitting on the shoreline, you cannot help but wonder what teems below the horizon, and how the ocean looked long before we were here.

From the surface, the sea can seem somewhat stagnant, with only tides and storms changing its behavior. Below the surface, however, we can see that the reefs are changing, in constant flux. Taking a closer look at what lies below, we begin to realize just how important the oceans and coral reefs are to our existence.

This is one of the few colonies of elkhorn coral in South Caicos waters.

Coral reefs are a conglomeration of many different types of organisms. The main building blocks are stony corals. These organisms lay down a skeleton of calcium carbonate, or limestone, and are covered by a thin layer of tissue. Within this tissue live zooxanthellae that create their energy from the sun, a process known as photosynthesis. The corals provide a home for these zooxanthellae, and in turn, the coral uses the algae’s photosynthetic waste for energy. Zooxanthellae also provide the corals’ beautiful colors.

Although most corals predominantly get their energy from zooxanthellae, they can also eat and are actually carnivorous! At night, they extend their polyps—tentacle-like structures—and wait to catch zooplankton that float by.

Early reef monitoring
So where did our modern research of coral reefs begin? Most research is fairly recent due to the difficulty of studying a habitat that was, until recently, simply beyond our reach. The “Aqua-Lung,” a demand valve system that supplied compressed air and was invented by Jacques Cousteau and Emilie Gagan in 1942, opened the doors for recreational SCUBA diving, and made studying marine life more accessible.

Starting in the 1970s, Phil Dustan and John Halas began monitoring Carysfort Reef off of Key Largo, Florida, on behalf of the Key Largo National Marine Sanctuary.

In 1975, there was a field of Acropora palmata, or elkhorn coral, surrounded by fish and a clean blue ocean. The live coral structure is very rugose—it has a lot of vertical structure, or nooks and crannies, where fish and invertebrates can hide. Just 10 years later in 1985, the reef starts to turn green—much of the once-dominant elkhorn coral is beginning to die and become overgrown by algae. In 2004, live coral tissue is scarce to find in the picture, and mostly dead coral rubble, or skeleton, remains. In 2014, the rubble is overgrown by algae, the reef has lost much of its rugosity and is mostly flat. What happened to that beautiful reef that existed back in the 1970s?

The perils of overfishing
This photo set from the Florida Keys isn’t unique— many different factors play a role in most of the Caribbean coral reefs facing similar challenges. Ever-increasing populations throughout the world increase demand for sources of protein. For coastal communities, this often means fishing to sustain their families, which leads to overfishing if populations of fish species aren’t kept in check. This particularly affects reefs when the herbivorous fish numbers begin to drop. Without these fishes munching on algae and controlling their levels, the algae begins to grow unchecked.

Furthermore, in the 1980s, a disease affecting Diadema antillarum, or the long-spined sea urchin, began to spread throughout the Caribbean, drastically decreasing their numbers. Like herbivorous fishes, these sea urchins also gnaw away at algae. Without these grazers, algae then begin to smother corals, who need sunlight to sustain themselves and grow. Without these grazers, algae can also impede new corals from settling on rocky areas.

Coral bleaching

This coral colony is hundreds of years old, yet is being overgrown by algae and partially bleached.

Coral bleaching events are also stressors that can cause corals to die. Increased water temperatures and light intensity can cause the system that turns that light into energy to break down, leaving an overabundance of reactive oxygen molecules, which damage the zooxanthellae and the coral. The zooxanthellae that provide most of the coral’s energy are expelled from the coral, leaving behind a white tissue. If temperatures remain warm and don’t give the zooxanthellae an opportunity to re-colonize within the tissue, the corals are likely to die.

Ocean acidification
Ocean acidification is another very real threat for coral reefs. As humans produce more and more carbon dioxide as a byproduct of manufacturing, transportation, refrigeration and cooling, oceans end up absorbing most of it. When carbon dioxide and water mix, a series of chemical reactions occur which result in the seawater becoming more acidic.

The problem is that many organisms in the ocean, from corals to mollusks, rely on limestone, or calcium carbonate, to build their skeletons or shells. This increasingly acidic ocean water makes it that much more difficult for these organisms to build their homes and skeletons, and can even cause shells to dissolve!

Furthermore, different diseases have become more prevalent within recent years; Stony Coral Tissue Loss Disease is a very real, current threat to corals as it causes the corals’ tissue to slough off of the skeleton.

A valuable asset
What would we miss without these coral reefs? Tourism to areas with coral reefs is estimated to be worth about $35.8 billion globally every year. Diving on the reefs of the Turks & Caicos Islands was worth an estimated $8.3 million per year in 2005, with other reef-related tourism bringing in at least $9.8 million annually. Reefs also provide a large amount of storm surge protection, and their rugose shape absorbs much of the shock from storms and hurricanes. Every year, the estimated value of flood risk reduction provided by US coral reefs alone is more than $1.805 billion.

Besides all these facts and figures, however, it is important to consider future generations. Ultimately, a dollar amount can’t begin to encapsulate the beautiful natural reefs just outside our doors.

SFS staff and students monitor South Caicos reefs.

Hope for the future
Despite drastic changes in our reefs, we must remember that although corals are facing serious problems that must be acted upon, we also have to regain hope. Hope that these corals have the opportunity to bounce back depending upon how we move forward. Countless organizations, foundations, and researchers worldwide are working tirelessly to fix our broken system of consumerism to quell climate change, to study these crucial coral reef communities, and to raise awareness of these issues.

Locally, the Turks & Caicos Reef Fund, based in Providenciales, is working on many projects including reef restoration via offshore coral nurseries and disease mitigation to stop the spread of Stony Coral Tissue Loss Disease on individual coral colonies. At The School for Field Studies Center for Marine Resource Studies on South Caicos, we invite undergraduate students to study abroad and research these pressing questions about coral reefs and study populations of other vital marine life right in our backyard.

How can you help?
What steps can you take to help make a positive impact on these beautiful reefs? Climate change is currently the biggest threat not only to our coral reefs, but to most of our islands and the entire globe. Coral bleaching, ocean acidification and even changing ocean currents ultimately stem from our changing climate.

Taking this into consideration, a solution might be living simpler. Try to drive less and bike or walk more in order to cut back on those carbon emissions and save money at the same time. Experiment with making and eating more vegetarian and vegan meals and less red meat, as carbon emissions from raising and transporting cows is actually high.

Use the Monterey Bay Aquarium’s Seafood Watch website,, whenever thinking about purchasing fish at grocery stores or restaurants to see how sustainable and healthy your choice may be. For instance, by switching to tuna caught from handlines, much less bycatch (unintended catches such as sharks, dolphins, etc.) will occur than those caught by longlines.

Generally, consume less, try to reuse old belongings, and keep an eye on how many single-use plastics, such as utensils, straws and packaging, you use. Trying to have a positive impact on our world and environment can often seem overwhelming; how can one person make a difference? But keep in mind that your choices do matter on a personal level, and you can use your knowledge to educate others and help them make responsible choices as well. The world is in your hands!

For more information, contact SFS Center Director Heidi Hertler, PhD at

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