Artificial reefs make big splash. They create offshore ecosystems for fish, coral, and divers

The sunken freighter looks like an eerie underwater ghost town, with long passageways crusted with waving tentacles of coral and brightly colored fish darting this way and that. The divers have inched their way down a lead rope for five minutes to get to the ``Mercedes.'' You remember the Mercedes? The 496-ton freighter that ran aground in socialite Mollie Wilmot's West Palm Beach back yard on Thanksgiving Day 1984? The one they're making a film about, starring Bette Midler? Well, this is where it ended up -- at the bottom of Pompano Bay, Fla.

It's not alone. The Mercedes, which was dynamited and sunk in March 1985 by the Environmental Quality Control Board in Broward County, Fla., as part of its artificial reef program, is one of 30 freighters, oil rigs, tug boats, hull molds, gas tanks, and an airplane that have been sunk here since 1981.

``We don't `sink junk,' '' cautions Steve Somerville, a coastal engineer for the board. ``We `deploy artificial reefs.' '' Reefs shelter fish from predators and provide a hard surface for coral to grow on. Mmany natural reefs have been damaged by pollution and boat anchors, so artificial reefs create new ecosystems in unproductive areas. And these new reefs work quickly: Within one year of sinking the Mercedes, Mr. Somerville says, it was completely covered over with coral, sponges, algae, and swarms of fish.

``It's the one government program that doesn't have any detractors,'' says Somerville. ``It helps the ocean; fishermen like it because they always have a reasonable chance of catching fish here; the diving industry likes it, too,'' he says.

``It's great for the diving business,'' concurs Mike Becker of ProDive, a Ft. Lauderdale dive shop. Leaning on the mop he's swabbing a deck with, he explains: ``We run two trips a day to see the Mercedes; we've taken over 2,000 divers to see it.''

One diver just coming in from the reefs is Milon Cernkovic of Tampa, Fla. ``It's fantastic!'' he says, while rinsing off his gear. ``There's a real mystique about it. You think about the people that worked and lived on it.''

While figures aren't in for Florida, a 1977 study in South Carolina found that artificial reef fishing generated an economic benfit of $10.4 million, says Joe McGurrin, director of the Artificial Reef Development Center in Washington, D.C.

The Broward County artificial reef program works this way: The Environmental Quality Control Board buys the ships at federal auctions (sometimes they're confiscated drug-smuggling boats), strips them of furniture, takes off the doors, and cleans them.

The vessels are then loaded with 100 pounds of TNT and dynamited so that they will sink quickly and upright, the better to allow divers easy passage in and out and to keep them stable during tropical storms.

``We do it up big, add a lot of pyrotechnics,'' says Somerville. ``It's a big spectator sport around here.'' When they sank the Mercedes, he says, ``a hundred thousand peoplewatched from 1,000 boats and along highway A1A -- and that was in rough weather.''

That kind of visibility has brought lots of community support. Eighty percent of the total cost of the project is contributed from industry and private donations.

Tennaco Oil moved rigs (each one as tall as an eight-story building) on huge barges from Louisiana at a cost of roughly $750,000. The board also gets free oil removal, free tugs, and free dumpsters. The bomb and arson squad of the Broward Sheriff's Office does the dynamiting. The Florida Ocean Science Institute's alternative education program provides young volunteer assistance.

``The kids love it -- it's destroying something, and they love that,'' says Somerville gleefully.

The Mercedes has a counterpart: Palm Beach County sank a donated $25,000 Rolls-Royce, something Somerville frowns on. ``That's a bad example. You know how fast cars rust out. We're trying to create a long-term, stable ecosystem.'' Artificial reef building has been going on in the United States since the '60s. The Japanese are world leaders in reef development and have developed a highly successful fiberglass-reinforced plastic unit that can be adjusted to the terrain.

These fiberglass units are not used much in this country because they are available in limited quantities -- and only in Japan.