By KEVIN LOLLAR, klollar@news-press.com


Diving the battered Florida reef tract these days is a little like walking through a bombed-out city.

In each case, the incomplete destruction gives a sense of immeasurable loss. Florida’s reef tract, which runs the length of the Keys, is the most extensive coral reef system in North America and, after Australia’s Great Barrier Reef and the barrier reef of Belize, the third largest in the world. It is also the Keys’ lifeblood — according to a recent study, tourists and residents spent $790 million on reef-related activities from June 2000 to May 2001. But the Keys’ reefs, like reefs throughout the world, are in serious trouble. Once-colorful and vibrant coral heads are ghastly white, blotched and pocked with disease; coral colonies are choked with algae or smothered by sponges; calcium carbonate rubble — coral skeletons — litters the sea floor. “My first dive on a coral reef was in 1958 in the Keys, and I’ll never forget massive stands of staghorn coral and the enormous groupers,” said Mike Risk, a professor of geology and biology at McMaster University in Hamilton, Ontario. “I was 30 feet deep off the Grecian Rocks, and I was followed all day by a 100-pound grouper. “That guy’s not there anymore. The branch corals aren’t there anymore. Time’s up. You don’t have a coral reef anymore.”

Coral cover These aren’t the nostalgic musings of a man to whom the old days are always better than the present. Risk’s perception of a dying coral reef is quantifiable. Since 1996, the Florida Marine Research Institute has documented coral cover at 43 sites from Key Largo to the Dry Tortugas — coral cover is the percent of a reef that actually has coral growing on it. A healthy reef has 30 percent to 40 percent coral cover; in 1996, the research center documented 10.3 percent coral cover, REEFS: Subpar water quality to blame for much of destruction which dropped to a low of 6.4 percent in 1999. “I go back 30 years in the Keys, and back then most reefs had very healthy and vigorous growth, 30 to 40 percent cover,” FMRI research scientist Walt Jaap said. “I’m depressed, too. To compare what it was like in the ’70s to today is not exactly a euphoric feeling. We are documenting the downfall of it.” Diseases Many things can kill corals, including boats, scuba divers and hurricanes, but scientists are looking at other causes of death: disease, algae and a very nasty sponge. Seven coral diseases have been documented in the Keys — black band, yellow band, white band, white plague, white pox, dark spot and aspergillosis (also known as sea fan disease). A relatively new disease on the block is white pox, which was first documented in 1996 on Eastern Dry Rocks reef off Key West and only infects elkhorn coral. James Porter, a University of Georgia professor of ecology and marine sciences, has identified the human fecal bacterium Serratia marcescens as the cause of white pox. “White pox is bad in the Keys,” Porter said. “It has killed 85 percent of all the elkhorn coral. Off Key West, that figure stands at 98 percent. “Human populations in the Keys are growing, and in addition, the septic systems in the Keys are leaky. As a result, the average length of time it takes between the flush and the ocean is 7€ hours, so you have all this material pouring onto the reef.” Something more must be at play, though, Porter said. After all, the bacterium has been leaking into the sea around the Keys for years, but the disease didn’t show up until 1996. Porter thinks the answer is global warming, which has raised sea water temperatures. “A warmer world will be a sicker world,” he said. “If you want mold on a loaf of bread, don’t put it in the refrigerator. Elevated temperatures favor the microbe.” Increased nutrients, particularly nitrogen and phosphorus, are another factor, Porter said. “Elevated nutrients also favor the microbe,” he said. “In that sense, a polluted world will also be a sicker world. The fact of the matter is we know nitrogen and phosphorus concentrations are increasing. Now the question is where is it coming from?” Another great concern is white plague, which affects mounding and plate corals and is caused by a bacterium of the genus Sphingomonas. “It can proceed very quickly and is obviously contagious,” said Erich Mueller, director of Mote Marine Laboratory’s Center for Tropical Research on Summerland Key. “We had a hot spot in the Dry Tortugas preserve where 25 percent of the corals were infected. That’s high. If 25 percent of the people in Florida had one fatal disease, everyone would be alarmed.”

Coral bleaching Coral bleaching, which some scientists don’t consider a disease because it’s not an actual infection, is a major concern, Mueller said. Simply put, coral bleaching is a breakdown of a relationship between coral polyps and algae. The algae, called zooxanthellae, live in coral tissue where they carry on photosynthesis and supply coral polyps with energy and oxygen. When the polyps become stressed, they expel their zooxanthellae — because the algae transfer their color to the clear, colorless coral polyps, the loss of the algae leaves the coral white, or bleached. If the stress disappears, zooxanthellae return and the corals get on with their lives; but if the stress continues, the algae don’t return, and the coral polyps die. Over the past 20 years, bleaching has increased dramatically worldwide, and as with coral diseases, warmer seas are part of the problem. Other factors such as pollution, below-normal salinity and high light intensity also can stress corals and cause bleaching. “When bleaching occurs, it can be devastating to many species of coral over a large area,” Mueller said. “In 1997, we had a lot of disease and a lot of bleaching. We also had high water temperatures. We suspect that increasing water temperature increases all disease.”

Boring sponge Its scientific name sounds like a villain in a Disney movie: Cliona delitrix; its common name sounds like a tedious sunburned moocher: red boring sponge. Truth be known, little good can be said about this primitive animal, whose diet consists of elements in fecal matter. “This thing eats poop and kills sponges,” said Risk, who discovered the sponge in the Cayman Islands in 1985 and was the first to identify it in the Keys in 1996. “In the Caymans, there was this green turtle farm with about 300 turtles for sale. All the poop went down this little channel and into the sea, and we said, ‘Hmm. Here’s a point source of poop in the water.’ “So we dove down, and there were all these friggin’ bright-orange sponges. The more bacteria you have in the water, the more you see these bright-orange critters.” Cliona delitrix attacks corals, especially large slow-growing species such as brain and star corals, by boring inside and starting to grow. “It doesn’t eat the coral,” Risk said. “It uses the coral as a cheap way to grow its own shell. When it gets motoring, it spreads across the surface. “It’s like chickenpox: You get sniffles first, then you get the blotches. You don’t see the sniffle stage. By the time you see the sponge, the coral is infected.” The sponge spreads to the coral’s surface within a year, then grows about 1 foot per year until it completely envelops the host coral. “It’s said that nobody dies of AIDS: People die from something they catch because their immune system is weakened,” Risk said. “You guys couldn’t be getting a clearer message that there’s too much crap in the water. “Whether the boring sponge is the biggest threat to the reef — it’s a matter of what the reef is going to die of. We’ve weakened it to the point where I think the whole reef tract is extinct.”

Algae When great globs of macroalgae — what many people call seaweed — appeared on the reef tract and started smothering corals several years ago, many scientists said the culprit was upwelling: cold, nutrient-laced water that welled up from beyond the continental shelf. Brian Lapointe, an algae expert at the Harbor Branch Oceanographic Institution in Fort Pierce, disagreed. Lapointe said the macroalgal bloom was triggered when the South Florida Water Management District increased the flow of fresh water into Florida Bay in an attempt to clear up a microalgal bloom, which was caused by high salinity in the bay. All that fresh water carried nutrients from the Everglades Agricultural Area into the bay; the nutrients fed the macroalgae and the macroalgae rolled out onto the reef, Lapointe said. Using data he has collected for 20 years at Looe Key, LaPointe said macroalgae appeared on the reef any time fresh water flows into the bay were increased. “Fresh water made it much, much worse, carrying nitrogen into the bay and causing more and more algae,” Lapointe said. “That’s been the single biggest problem. Of course, sewage is right up there with it. It’s really a double whammy.” If Lapointe is right, the proposed Everglades restoration, which calls for increased freshwater releases into Florida Bay, would be a recipe for algal disaster. “The idea is that hypersalinity is causing the problem, so you put more water into the bay, and that makes everything better,” Lapointe said. “More likely, what they’re planning will make things much, much worse in the bay and beyond.” Army Corps of Engineers scientists agree that Everglades restoration could hurt the reef tract. “It’s a big concern if we don’t do it properly,” Corps biologist Brad Tarr said. “There’s a lot of nitrogen from the agriculture fields, and we’ll be monitoring to make sure existing levels of nitrogen are not exceeded with increased freshwater flows.”

Urchin die-off Algae are a natural part of any coral reef system, and under normal circumstances, they are kept in check by predators. Historically, an important algae predator in the Caribbean region was the long-spined sea urchin, Diadema antillarum. In 1983 and 1984, however, a disease of unknown origin wiped out 95 percent of the region’s Diadema population, and algae increased dramatically on coral reefs. Florida Marine Research Institute scientists keep an eye out for Diadema as they do their coral cover surveys. “Diadema’s not doing very well in the Keys,” Jaap said. “When we sample, we see no more than five a year on our sites. “There are two parts of the algae equation: If you don’t have Diadema, which are the main foragers for algae, and you have an increase of nutrients, algae do well.” Diadema populations are having a surprisingly difficult time becoming re-established, and scientists are not sure why. Jaap said one reason might be that Diadema is a favorite menu item of such predators as triggerfish, and with so few reproducing, any new urchins on the reef are quickly snapped up.

Fish counting One of the biggest attractions of any coral reef is the wildlife: Divers and snorkelers love to look at and photograph the neon-bright reef fish or the sinister-looking barracudas and sharks; fishermen love to catch snapper or grouper. So what happens to the fish if the reef dies? Recent studies show that fish populations in the Keys are down, but at this point, overfishing rather than coral loss is behind the decline. If the reef continues to crash, though, fish numbers will continue to shrink. “Fish will hang around quite a while as long as the three-dimensional structure is there,” Mueller said. “Over time, through the forces of erosion, the structure will become less complex as little pieces break off. Eventually, it will become a sand plain, and not much lives on a sand plain.”

The solution Florida’s reef tract is under assault by many destructive forces — anchors, divers, storms, global warming, diseases, bleaching, boring sponges, algae. Nothing can be done about storms; little can be done about climate change; boaters and divers can be educated. But human waste aggravates all the reef’s woes, so the best way to save the reef is to clean up the water pouring onto it from the Keys. About one-third of the Keys’ 85,000 permanent residents are on a central sewage system; the rest of the Keys’ sewage goes to a leaky system of 6,000 cesspits and 24,000 septic tanks. “Here is the challenge to the people of the Keys: Improve water quality,” Porter said. “The way to do that is to go to advanced waste-water treatment standards. One, advanced wastewater treatment will remove nutrients, and, two, it will remove microbes. Any step we take to improve water quality in the Keys is a step in the right direction.” Keys government is taking the first steps: By 2010, the Keys will have a new $430 million central sewage system in place, said Tim McGarry, Monroe County director of growth management. The project will be paid for with county taxes and grants from such agencies as the Federal Emergency Management Agency and the Florida Department of Community Affairs. Congress authorized $100 million for the project in 2000 but has not yet appropriated the money. “I guess there are arguments that this won’t have much of an impact,” McGarry said. “But most people have reached the conclusion that something must be done with the current sewage system, or lack of a system. We are going with a very advanced system. It will be very clean.” Even this expensive step might be too little too late, Risk said. “I’m retiring early: I’ve talked to you for 15 minutes and succeeded in depressing you; think about how I feel,” he said. “We’re looking at a regional extinction of coral. I know my grandchildren will be fortunate to ever see a living coral reef. And it probably won’t be in the Caribbean. They’ll probably have to go to some remote corner of the Pacific.” Not everyone is so pessimistic. Billy Causey, manager of the Florida Keys National Marine Sanctuary, which encompasses the entire Keys’ reef tract, pointed out that some remote reefs still have 40 percent coral cover. With proper management of human activity, he said, other parts of the reef tract can approach the same kind of health. “What I believe is that our coral reefs are in serious trouble,” Causey said. “I went to Looe Key reef recently. It’s one of my favorite places on Earth, and it was absolutely heart-wrenching to see the decline of the reef since I started diving there in the early ’60s. “But I don’t think our coral reef is beyond hope. We’re starting to learn more about it, and that gives us hope that we can sort some of these things out and deal with them.”