ng up to the barge, which will remain anchored above.
Generators on the barge will power the habitat. A desalinization machine will purify seawater and supply a steady stream of fresh water. Pumps will ensure a continuous supply of air.
A cook on the barge will prepare meals daily. Dinner will be delivered via airtight containers.
The key feature of the habitat is that it will allow scientists to dive for much longer periods of time than they could from a boat.
Traditional divers can carry only so much compressed air and must limit the time they spend at deeper depths, because nitrogen builds up in their blood. With Aquarius, scientists will be able to spend full days diving. Aquarius is a decompression chamber.
Living underwater is nothing new. Scientists have been doing it since the 1960s.
Past projects include Tektite, which was submerged at St. John in the Virgin Islands between 1969 and 1971. Tektite was followed by Hydrolab in The Bahamas and St. Croix, Virgin Islands.
Aquarius was submerged near St. Croix for three years in the late 1980s -- a mission cut short by Hurricane Hugo in 1989.
Aquarius may be the most comfortable underwater habitat ever made. In Hydrolab, for example, the toilet was the ocean. Scientists had scant storage space and had to haul wet diving gear into their living areas.
"We had a hot plate that we boiled chicken tetrazini, turkey tetrazini, beef tetrazini in, and that's about it," said Walter Jaap, an associate research scientist with the Florida Marine Research Institute in St. Petersburg.
"When you're down for a number of days and you're doing hard work and then you come up and look at peanut butter and jelly sandwiches, it's pretty demoralizing."
Miller said likely studies include drilling into the ocean floor to study the quality of ground water below and examining water quality around the reef to help determine the effects of sewage pollution. Another plan is to set up monitoring stations that can be revisited to gauge the changing health of the reef.
Some scientists have questioned Aquarius' cost -- an estimated $1.5 million a year -- and whether it is the best use of limited research dollars.
"Underwater habitats capture people's imaginations. There's lots of good publicity," said Alina Szmant, a coral reef physiological ecologist at the University of Miami. "But they're very expensive."
Other scientists think Aquarius is the best thing since Jacques Cousteau -- and a boon for the Keys in particular.
"I would see (Aquarius) as a form of insurance," said Billy Causey, manager of the Florida Keys National Marine Sanctuary. "We need to know the very most we can about this very fragile environment. Otherwise, it can slip away and be gone before you even realize it."