Coral Reefs in the Gulf of Mexico

These magnificent underwater landscapes of color and biodiversity are under increasing threat from humans and climate change. Learn about the coral reefs near you and how you can help.

Oceans

GP Schmahl/NOAA | Public Domain
Flower Garden Banks National Marine Sanctuary

As Ocean Week kicks off today, we’re taking a look at Texas’ ocean – the Gulf of Mexico – and its beautiful network of coral reefs (some of the healthiest in the world).

The rainforests of the ocean, coral reefs are one of the most biodiverse places in the world. They support around 25% of all marine life while providing many other benefits. These include serving as a home and/or nursery ground, providing stock for some commercially-fished species, acting as a protective barrier from natural disasters such as hurricanes, supplying fishing opportunities for locals, sourcing new medicines, tourism, and recreation. 

Introduction to Corals

There are several different types of corals that compose these wondrous underwater landscapes. Hard corals, also called reef-building corals or stony corals, are those with calcium carbonate skeletons that… you guessed it… build the reef! These include staghorn, elkhorn, and brain corals, along with many more. Soft corals, including sea pens, sea fingers and sea whips, are non-reef-building corals that are able to bend in the water column, are stabilized by a wood-like center, and can catch prey should they get too close.  Unbeknownst to many, there are also deep-sea coral reefs that form from six species of stony corals at least 50 meters below the ocean’s surface in dark, cold waters. Because there isn’t abundant light, these corals get nutrients by feeding on sinking organic matter or plankton. Deep-sea reefs also display great biodiversity and color with populations of black coral, soft coral, invertebrates and fishes. 

Contrary to common belief, corals are actually not plants! Corals are animals – they are alive, but do not make their own food! Most reef-building corals are made of many colonies of polyps (animals) that pull calcium from the ocean water to create a hard base skeleton of calcium carbonate. This skeleton builds over time to expand the coral reef landscape. Polyps have a symbiotic relationship with an algae called Zooxanthellae which photosynthesizes and provides the polyps with energy, oxygen, and nutrients in exchange for shelter and nutrients. Zooxanthellae are also the reason for the beautiful display of color seen across shallow coral reefs. However, coral polyps expel the algae when under stress, which can lead to death if corals are without it for too long. 

Threats to Corals 

Coral bleaching

Coral reefs provide so much for both marine life and humans, yet they are highly threatened by anthropogenic practices and accidents, as well as natural occurrences. 

  • Coral bleaching happens when coral polyps expel Zooxanthellae as a result of stress and can lead to coral death in the absence of this symbiotic relationship. 
  • Oil drilling and oil rigs can result in spills that smother coral reefs and prevent the coral from accessing sunlight or expelling waste. 
  • Climate change causes multiple threats to coral including thermal stress (expel algae and promotes coral bleaching), ocean acidification (hinders coral growth), changes in sedimentation levels (possible coral smothering), changes in ocean currents and weather occurrences (hurricane damage, dispersal of food and larvae), and more.  
  • Diseases, like stony coral tissue loss disease or white plague, can cause lesions, tissue loss, and coral death. There is research currently underway at the East and West Flower Garden Banks off the Texas coast where an unknown disease was found in 2022 in star and brain corals. 
  • Trawling is when commercial, recreational, or scientific vessels drag a net along the ocean floor to catch bottom-dwelling animals or plants. This fishing strategy basically bulldozes everything in its path, making it incredibly harmful for vulnerable habitats like corals, especially deep-sea corals, which take a very long time to grow. 
  • Overfishing mainly impacts coral reefs that are not protected by law. While illegal fishing still occurs in marine protected areas or sanctuaries, unprotected reefs are often exhausted of many fish, like groupers, which removes and harms the biodiversity and balance of these ecosystems.
  • Human-caused damage like anchoring, taking, and pollution also cause physical damage to the reef, tie into other threats like climate change, and can alter/harm ecosystem dynamics.

Coral Reefs in the Gulf of Mexico 

The Flower Garden Banks Reef 

A marbled grouper swims along the reef in Flower Garden Banks National Marine Sanctuary.

The Flower Garden Banks Reef lies off the coast of Texas and Louisiana, and is the only marine sanctuary in the northern Gulf of Mexico. The sanctuary originally included just the East and West Flower Garden Banks, but now includes an additional 15 sites since the Office of National Marine Sanctuaries passed a federal law expanding the Flower Garden Banks National Marine Sanctuary in 2021.

It is home to an abundance of beautiful sea life: Manta rays, sea turtles, hammerhead sharks, whale sharks, many reef fish, and of course… corals! In fact, the sanctuary is famous for the enormous brain and star corals found there, although these types of corals are mainly found in shallow reefs such as the East and West Flower Garden Banks. A majority of the sanctuary actually lives deeper, in the mesophotic range. This means that there is much less sunlight at these reefs given the greater depth, so different species of coral thrive comparatively. Instead, black corals and octocorals are more commonly found in deep sections of the sanctuary like at Elvers Bank and Geyer Bank.  

An important component of the banks that make up this sanctuary is that many of the shallow banks were made possible because of the salt domes that lie beneath them. Millions of years ago, pressure from accumulating sediments caused salt layers on the ocean floor to push upward, either breaking through entirely or simply creating mounds out of the sediment on the seafloor. This movement creates cracks for oil and gas to accumulate which makes this region in the gulf a popular place for oil/gas exploration. Of course, this exploration comes with its threats as discussed previously.

Because the Flower Garden Banks Reef lies quite far off the coast and deeper than many other coral reefs, it is one of the most well-preserved reefs in the world. However, it is not immune to the same threats. While disease and rising ocean temperatures have shown more drastic effects in places like the Florida Keys and Caribbean, researchers have now seen impacts to this sanctuary too. The East and West Banks were bleached by 24% and 10%, respectively, in 2016, and “moderate” bleaching is already occurring since late last year. 

This problem heightens another; coral bleaching makes coral more vulnerable to disease. Researchers have continued to monitor and plan treatment strategies around the unknown disease found here in 2022.  It is vital to prevent this coral reef sanctuary from falling to these widespread harms like so many other reefs have because it could be used to help restore other, more damaged reefs in the future. 

Veracruz Reef System

The Great Star Coral (Montastrea cavernosa) is found in the Veracruz Reef System

The Veracruz Reef System comprises about 50 reefs (28 coral reefs) and spreads over 230 square miles. It has been protected as a national park since 1992, but due to its location near the coast, the reefs here are the most vulnerable in the southern Gulf of Mexico to anthropogenic threats including pollution, sedimentation, and coastal development.

Interestingly, this reef system has at least 18 submerged reefs, and this type of reef is understudied relative to other types. It is argued that more research is needed for these ecosystems in order to develop an effective conservation plan for the reef system as a whole. 

As a marine protected area (MPA), this Veracruz Reef System is recognized as a hotspot for biodiversity. Here, you can find species like elkhorn coral, green sea turtles, over 350 species of fish, and much more! In 2006, it was added to the list of Biosphere Reserves by the United Nations Educational, Scientific and Cultural Organization (UNESCO), and named a Ramsar Wetland of International Importance. These declarations supported the rejection of a port expansion project in 2022 in order to protect the adjacent reef ecosystem.

Alacranes Reef 

Scorpion Reef, north of the Mexican state of Yucatan, in the Gulf of Mexico is pictured from the International Space Station as it orbited 257 miles above.

This reef is a part of the Alacranes Reef National Park which lies less than 100 miles from  Progreso, Yucatán. The Alacranes Reef (Spanish for “Scorpion Reef”) itself is the largest coral reef within the southern Gulf of Mexico. It benefits many species including hawksbill, leatherback, loggerhead and green sea turtles, all of which are listed as endangered under the Endangered Species Act. This reef contributes so much biodiversity that it was nominated to join UNESCO’s Man and the Biosphere Programme (MAB) in 2006. 

The national park area also includes five land masses: Isla Pájaros (or Blanca), Isla Chica, Isla Pérez, Isla Muertos (or Desertora), and Isla Desterrada, which serve as important bird nesting sites. Alacranes Reef is also a marine protected area (MPA) and has two no-take zones. However, many large fish, sharks, and turtles are still fished from the site due to insufficient regulation even though isolation of the reef slightly limits human-caused implications.  

Florida’s Coral Reef

Beata Lerman | Public Domain
Florida Keys National Marine Sanctuary.

The coral reefs off the coast of Florida, over half of which are included in the Florida Keys National Marine Sanctuary (FKNMS), are mostly close to shore, don’t have inshore lagoons, and are therefore referred to as a bank-barrier reef. The FKNMS was designated as a marine protected area in 1990 and is still protected by the National Oceanic and Atmospheric Administration (NOAA), the Florida Fish and Wildlife Conservation Commission (FWC), and the Florida Department of Environmental Protection (DEP). 

These coral reefs are popular tourist attractions for the abundance of wildlife, clear waters, and even shipwrecks that now showcase Floridian history and artificial reefs. Many species of animals, including commercially valued ones, depend on these reefs for a juvenile refuge or lifelong home. For example, groupers, barracuda, and lobsters can all be found here. While popular, the coral reefs in Florida also face multiple threats including land-based pollution, warming ocean temperatures, coral bleaching, and Stony Coral Tissue Loss Disease. Efforts continue in an attempt to minimize these threats and ensure a stable coral ecosystem including the institution of the Coral Reef Conservation Program and Florida Reef Resilience Program

How Can We Protect Corals? 

Current law works to identify Habitat Areas of Particular Concern, impose fishing regulations in those areas, limit access, research and define components of coral reefs, and create assistive programs such as NOAA’s Coral Reef Conservation Program. However, much more still needs to be done in order to protect coral reefs from the ever pressing threats of human activities and climate change.  

While you may not think so, every person can do their part in everyday life to help coral reefs and the environment generally. Some actions include:

  • Dispose of trash correctly
  • Limit fertilizer use
  • Implement rain gardens or other green infrastructure to limit runoff
  • Walk or ride a bike to limit emissions
  • Be conscious of your energy usage
  • Ensure responsibly and sustainably sourced seafood or aquatic pets 

Should you visit one of these Gulf Coast treasures this summer, keep a lookout for bleaching events that will likely happen as ocean temperatures increasingly rise and patterns seen last year might continue.  Furthermore, remember to act responsibly and respectfully at the reef by not touching/taking any plants or animals, anchoring on a sandy bottom rather than the reef itself, and avoiding the use of sunscreen that has reef-harming chemicals.  

These underwater seascapes are one of the most important and awe-inspiring components of our planet. We owe it to ourselves, our oceans, and our environment to change our harmful practices and prioritize coral reefs around the world.

Topics
Authors

Catelyn Toney

Wildlife and Wild Places Intern

Catelyn is an intern at Environment Texas and student at the University of Texas at Austin. She is studying biology and hopes to work in environmental conservation.

Luke Metzger

Executive Director, Environment Texas Research & Policy Center

As the executive director of Environment Texas, Luke is a leading voice in the state for clean air and water, parks and wildlife, and a livable climate. Luke recently led the successful campaign to get the Texas Legislature and voters to invest $1 billion to buy land for new state parks. He also helped win permanent protection for the Christmas Mountains of Big Bend; helped compel Exxon, Shell and Chevron Phillips to cut air pollution at four Texas refineries and chemical plants; and got the Austin and Houston school districts to install filters on water fountains to protect children from lead in drinking water. The San Antonio Current has called Luke "long one of the most energetic and dedicated defenders of environmental issues in the state." He has been named one of the "Top Lobbyists for Causes" by Capitol Inside and received the President's Award from the Texas Recreation and Parks Society for his work to protect Texas parks. He is a board member of the Clean Air Force of Central Texas and an advisory board member of the Texas Tech University Masters of Public Administration program. Luke, his wife, son and daughters are working to visit every state park in Texas.