Turning the Tide?
"Turning the Tide?"
By: Mark Zaloudek
Date: October 8, 2004
Source: Zaloudek, Mark. "Turning the Tide? Scientists Hope that New Research, Reef-building Efforts and Public Support Can Help Reverse Decades of Damage to Florida's Extraordinary Coral Reefs." Sarasota Herald Tribune, October 8, 2004.
About the Author: Mark Zaloudek writes on a variety of topics for the Sarasota Herald Tribune.
The coral reefs off of the coast of Florida are some of the most threatened in the world. The reefs are being impacted by agriculture and urban water pollution, destructive boating and fishing practices, and environmental stresses such as global warming and hurricanes. It is documented that the last thirty to forty years have been extremely devastating, as many corals have died within this time period with minimal recovery.
Corals are small polyp-shaped animals with tentacles. They look like upside-down versions of their relative, the jellyfish. However, coral polyps are stationary. Corals and jellyfish are in the phylum Cnidaria, as both animals have stinging cells on their tentacles, which are used to catch food particles from the water. Corals found in the tropics have an important symbiotic relationship with an algae called zooxanthellae, which lives in the tissue of the corals. In addition to giving the corals many different colors, the unicellular zooxanthellae provide food nutrients to the corals by carrying out photosynthesis. The corals provide the zooxanthellae with protection, and access to light. Because the zooxanthellae need light, tropical corals cannot grow beyond the ocean's photic zone.
The base of a coral reef is made up of a large structures of stony calcium carbonate, which is excreted by coral polyps. Calcium carbonate is made when calcium is removed from the sea water by the corals, and combined with carbon dioxide. The mounds of calcium carbonate that make up the coral reef off Florida have been building up over the last 5,000 to 6,000 years. Coral reef growth requires warm and stable water temperatures, normal oceanic salinity, clear water, low levels of phosphate and nitrogen nutrients, and moderate levels of water movement that can circulate wastes out and bring plankton and oxygen to the reef. Depending on these water conditions, the reef growth rates are one to sixteen feet every 1,000 years.
To better understand the corals, many studies have been designed to track the effect of various impacts on the reefs. Evidence links increased human impact with the health of coral reefs. Water pollution from urban areas, acid rain, boats, and other sources can bring toxins, including heavy metals, that are damaging to the reefs. Runoff from agricultural fields and sewage treatment plants are thought to increase the levels of nitrogen and phosphorous nutrients in the coastal waters. It is thought that such stresses make corals susceptible to disease.
Coral reefs also receive physical damage from tourists, divers, improper boat anchoring, and boat groundings. Overfishing and removal of important reef organisms can alter important symbiotic relationships on the reefs, making corals defenseless against certain predators. Strong hurricanes can often have a devastating impact on reefs.
Scientists note an increase in instances of coral bleaching, which occurs when the symbiotic zooxanthellae leave the coral polyps. In addition to giving coral a white color, without the zooxanthellae the coral does not receive all of the oxygen and nutrients it requires. Prolonged bleaching causes the coral to die. Bleaching is a sign that corals are stressed. This can be from pollution, turbidity of the water, and changes in sea temperature. One probable cause for bleaching is the increase in sea water temperature as a result of global warming.
Scientists hope that new research, reef-building efforts and public support can help reverse decades of damage to Florida's extraordinary coral reefs.
It's taken only 30 years to threaten coral reefs that have flourished along the Florida Keys for more than 5,000 years.
"These are the only coral reefs along the continental United States and they're in very bad shape," says coral researcher Kim Ritchie, Ph.D., a marine scientist at Sarasota's Mote Marine Laboratory.
"They're worse off, really, than any other corals in the Caribbean. And the Caribbean corals are in worse shape than the other corals around the world."
That may not trigger an alarm if you're not a scuba diver or snorkeler who has marveled at the aquarium-like splendor of Florida's living reefs, the third-largest in the world after Australia's Great Barrier Reef and the extensive reef off Belize in Central America.
But perhaps it should.
More than three million people annually visit Florida's 220-mile reef tract that stretches from Miami to the Dry Tortugas past Key West. Along the way they spend an estimated eight hundred million dollars at tourism-related businesses, boosting state revenues that support essential state services.
And if you like seafood, the waters surrounding the reef produce more than twenty million pounds of commercially harvested seafood each year.
Coral reefs have been compared to tropical rain forests because of their dense biodiversity and fragile ecosystems. Florida's reef tract is home to more than 60 reef-building corals and more than 150 species of fish.
Some shallow-water and deep-water corals can be found elsewhere along Florida's coastline, but their greatest concentration is along the state's southern tip.
Bill Causey, manager of the Florida Keys National Marine Sanctuary, calls the reef tract a "national treasure" in serious trouble.
"Some portions of the reef have died—as much as 30% in a very short time frame, while other areas have had less decline. But the end result is we've seen a major decline n the Florida Keys over the last three decades, with the greatest decline occurring in the 1990s," he said.
Environmental changes, humans share the blame.
Part of the problem is environmental changes. Fluctuating sea-surface temperatures that some scientists attribute to global warming are interfering with the beneficial algae that live on the corals and provide them with nutrients.
As a result, acres of corals that have become temporarily stressed appear "bleached." Many have died when their conditions didn't improve after as little as a month or two, Causey said.
The pounding surf from hurricanes squarely deserve the blame for other setbacks.
Pollution from septic tanks throughout the Keys and storm water carrying fertilizers and other nutrients into South Florida's coastal waters have placed the string of reefs in jeopardy.
At least seven coral diseases have been documented along the reef.
Boat groundings and other careless actions by recreational boaters, anglers, snorkelers and scuba divers, compound the problem.
Officials at the Florida Keys National Marine Sanctuary and others have closely monitored whether more than two hundred million gallons of treated industrial waste water dumped last summer and fall into the Gulf of Mexico 120 miles off Florida's west coast brought harm to the reefs as it migrated southward. The discharge was authorized by the state to reduce the risk of an environmental disaster at the abandoned Piney Point phosphate plant, south of Tampa Bay.
"The closest the discharge came to the Keys was when it came about seventy miles to the west of the Dry Tortugas. And to the south of the Keys, it was about thirty miles off shore," Causey said. Although the treated water contained phosphorus, which can produce harmful algal blooms, it was sufficiently diluted so as not to pose a threat, he said.
The reef tract can be affected by other pollutants entering the Gulf, though.
Forty percent of the U.S. land mass drains into the Gulf of Mexico, and pollutants carried from the land into rivers and streams eventually flow past the Florida Keys, Causey said.
The Fort Pierce-based Philippe Cousteau Foundation is helping advance the development of a coral bank that would maintain a genetic stock of coral species and reproduce them for transplantation back into the reefs.
The foundation, named for the late environmentalist and Emmy Award-winning filmmaker who was the son of legendary oceanographer Jacques Cousteau, is headed by Jacques Cousteau's twenty-four-year-old grandson, marine scientist Philippe Pierre Cousteau.
"There are over sixty species of Caribbean corals, and at the moment we have at least ten species we're growing," Ritchie said of Mote's coral aquaculture program. "But within months, our goals is to have many more species and, ultimately with the help of the Philippe Cousteau Foundation, the goal is to have representatives of a majority of the corals worldwide."
Experts believe the next several years could be critical to the survival of the Florida reef tract.
"What we have to do is address all the problems at the same time: the pollution issues at the local level, but also the bigger issues at the regional and global levels," Causey said.
"You just don't fix things at the local level and forget what's happening on a regional and global scale because then perhaps you'll have done this for nothing. But at the same time, you can't just address this at the global level and miss things that could have made a difference locally."
Coral reefs are considered one of the world's most biologically diverse ecosystems on earth, and provide many important services. The coral reef acts as an important breakwater, sheltering the Florida coastline from storms. Corals provide important habitat and breeding areas for many types of plants and animals and contribute to Florida's economy. Many tourists spend money to snorkel or SCUBA dive around the corals. Millions of dollars are generated through recreational and commercial fishing that occurs on the reefs. Small hard and soft corals, and many other organisms that grow on the reef, are sold in the aquarium industry. The National Oceanic and Atmospheric Administration estimates that coral reefs generate $4.4 billion in sales and employment.
The contribution of reefs to Florida's economy, as well as general concern for the reefs, has generated support for further studies of corals, and the development of management strategies to prevent coral degradation. Work is also being carried out to regenerate reefs through aquaculture methods. Species of corals are raised in laboratories or in areas of the sea that can support their growth. Then, these corals can be placed on reefs, in hopes of bringing life back to some of the degraded areas.
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