Shark tanks done


coral reef repairs nearly complete

January 23, 1995|By Edward Gunts | Edward Gunts,Sun Staff Writer

Visitors to the National Aquarium in Baltimore are accustomed to seeing fish in the tanks, but this weekend they saw people there.

The people on display were "artisan-construction workers" putting the finishing touches on the Atlantic Coral Reef exhibit, preparing for its reopening April 7 after an 18-month renovation.

Over the past several days, the exhibit designers and fabricators have been painting the staghorn corals, star corals, brain corals and other textured formations on the simulated reef so the exhibit could be filled with water for the first time since its closing for repairs in 1993.

Water began trickling into the 300,000-gallon tank yesterday morning. No leaks were reported.

"It's exciting to see water in that exhibit and the coral getting submerged after all this time," said Kathy Sher, the senior staff member on duty there yesterday. "Already, we can tell it's going to look lovely. The colors are dazzling."

The Atlantic Coral Reef exhibit is one of two oval-shaped tanks that constitute the aquatic centerpiece of the 14-year-old aquarium on Pier 3. Its companion is the Open Ocean shark tank, which reopened last month after its overhaul.

Their racetrack configuration was designed by Cambridge Seven Associates to give visitors the sense of being surrounded by water and fish -- and of descending deeper and deeper into the ocean as they walk down concrete viewing ramps in the middle of the tanks.

Both tanks were closed in October of 1993 so contractors could repair physical damage caused by the corrosive effects of saltwater on the concrete and underlying steel structures. Workers also have upgraded the life support systems and introduced other technological advances. The project cost $14 million.

Aquarium officials decided that as long as they had to drain the tanks, they should redesign the exhibits to make them more realistic.

The remodeled shark exhibit has darker walls designed to evoke the ocean depths, and new fiber-optic lighting to improve visibility.

The coral reef exhibit has taken longer to complete because it was more elaborate and needed more attention from the fabricators, Exhibit Technology Inc. of Littleton, Colo., and David Manwarren Corp. of Ontario.

The 15-foot-high reef was made off-premises from fiberglass-reinforced concrete in California to simulate Caribbean reefs. It was shipped to the aquarium, where artisans have been installing it for several months -- finally using colorful paint to highlight portions of the reef.

For most of the time, the workers and their growing reef were hidden behind the walls of a temporary laser-light exhibit called ImaginOcean. But last week the temporary exhibit came down, enabling visitors to watch the artisans completing their work.

Aquarium executive director David Pittenger said the new reef does not represent any one specific environment. Instead, he explained, it was sculpted to be a composite of the many reef conditions a diver might find in nature, compressed to fit into the narrow confines of the aquarium's ring tank. Micro-habitats such as ledges, overhangs and caves are expected to draw out more natural animal behaviors of the inhabitants than the old reef did.

"It's accurate from a biological point of view," Mr. Pittenger said. "This is going to be the best coral reef exhibit in the country."

The reef is denser than the old one and will have more different species of tropical fish on display, said Mark Donovan, senior director of exhibits and design. In addition, it was built closer to the aquarium's curving glass windows so fish would have to swim closer to their human observers, he said.

Mr. Donovan said the fabricators made a conscious effort to create a "fore reef" and a "back reef" inside the tank, to simulate the side of a reef that faces land and the side that faces the sea.

They also used flexible materials for the first time to simulate soft corals such as sea fans, sponges and gorgonians. Before, Mr. Donovan said, those objects were made of rigid materials, but now they are made of a flexible urethane that will enable them to sway with the current and bend when fish swim by.

Staffers will spend the next few weeks filling and draining the tank to flush it out and make sure its new filtration system works properly. When they are satisfied, the tank will be filled with salt water and aquarists will begin introducing the 700 to 800 living specimens.

"The tank may be filled and emptied out two or three times to make sure the water is clear and pure and there are no problems," Ms. Sher said. "The exhibit has to be right for the coral and perfect for the animals."

The repaired tank is expected to last for 20 to 25 years. Although the exhibit modifications are a collaborative effort between aquarium staffers and outside consultants, Mr. Donovan said, he is proud that the staff took the lead.

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