There's a place in Minnesota where temperatures don't tumble, snow doesn't fly and water never seizes into ice. It's a magical realm of shimmery blue water where dolphins dance, sharks prowl and otters wriggle and play: the Minnesota Zoo.

In charge of the magic is aquarium supervisor Allan Maguire, a tall, thin and bespectacled man who works out of sight in a squat concrete building filled with pipes, pumps and tanks. He takes Minnesota groundwater, adds a dash of "Instant Ocean," turns the crank and -- presto -- makes a home where exotic ocean fish thrive. With tons of pickling salt from Cargill, he conjures up a different water fit not for fish, but for mammals of the seas.

"This is where Minnesota connects with the ocean," Maguire says with pride.

In his green polo shirt and khaki pants, the 53-year-old Iowa farm boy seems as far removed from his roots as that Kansas wizard who landed in Oz. But it was Maguire's love of fish that propelled him to the zoo 27 years ago. He had a boyhood aquarium, all right, stocked with fish from the town's filling station. ("It just happened to sell fish," he explains. "In small towns, you have to be creative.")

His first job in Iowa, naturally, involved pigs -- not fish. Fresh out of college and armed with degrees in biology and mathematics, he worked in research to develop a baby-formula recipe for piglets. But it was news of a new zoo that sent him north in 1981. He worked his way through the Minnesota Zoo's habitats and grew and evolved along with the facility, landing at last where he wanted to be, supervisor of aquariums and life support at a zoo that spans 485 acres and entertains more than a million visitors a year. He now oversees about 5 miles of pipes, 70 pumps and 66 tanks holding from 20 to 1 million gallons of water.

With so much water used at the zoo, the magic has to be handled in an ecological way.

"It's not like the home aquarium where you dump the water and fill with new," Maguire said. It's a complicated recovery process, where water and salts are recovered and reused. The dirt and "biological load" (feces and urine) are filtered out and then flushed into sewer lines.

Leaning over a computer keyboard, one of Maguire's assistants turns pumps on and off, moves water around and cleans water by clicking commands on the colored schmatics of the zoo's plumbing system.

"It's like Jurassic Park, except we aren't dealing with raptors here," Maguire said with a laugh. "Sharks aren't going to get out and eat people." But things do go wrong, and when they do, alarms sound and Maguire springs into action. These are wonderful animals, he said, and expensive. "A sand tiger shark costs $5,000, and another $5,000 to ship it here. There's some $10,000 invested in this one animal." There's no room for error.

Learning and teaching

The magic isn't always perfect, or easy. In the beginning, as he learned to master the care of aquariums, Maguire scooped out plenty of dead fish. That's no longer the case. But in 1987, one of the two beluga whales, stars of the zoo, became gravely ill and both were transported to San Diego, where they eventually died. It cast a shadow over the workings of the zoo. Turns out the problem wasn't the zoo's water, but nature's.

"Hudson Bay, where they were captured, was so polluted, the animals got sick and died with cancer," Maguire said. "Nothing the zoo could have done would have changed that."

Zoos have their detractors -- people concerned about animals snatched from their ocean homes and confined to viewing tanks. But Maguire takes it as a personal challenge to keep the water displays as natural as possible, and to teach and explain.

"For about 90 percent of the public, this is as close as they are going to get to this wildlife," he said. "Few, if any, will see these animals in the wild."

The sight that upsets visitors the most, the sight that sends them running to guest relations, he said, is when one shark bites another. Then his job is to calm them down. Maguire explained that when a male shark gets amorous, he bites the dorsal fin of the female and hangs on. They aren't eating each other. It's how they get baby sharks at the zoo.

Reproduction isn't always encouraged. Try as they might, the sea otters won't make any babies. They're on birth control, Maguire said. Found as orphans in their native Alaska, the otters are actually owned by the U.S. Fish and Wildlife Service. The service says no more sea otters, and the zoo obliges.

Twice a week Maguire dons a dive suit and, wired for sound, submerges himself into the Coral Reef tank to answer questions from visitors, the most common being: "Do you like your job?"

Maguire always says yes, of course, it's a wonderful job. Although it's not as romantic as many people think.

"I'm a zookeeper, meaning 65 percent of the job, by description, is cleaning," he said. "I'm an animal janitor."

Karen Youso • 612-673-4407