BENEATH THE GULF OF MAINE — As the yellow submersible Delta slips beneath the Gulf of Maine 22 miles off Massachusetts, bubbles form outside the portholes and the craft enters a different world.

The tiny, two-person sub skims the sea floor, scattering fish and moving noiselessly through rocky canyons. This once-in-a-lifetime experience 200 feet underwater is part of a program for high school students, designed to bring the reality of the ocean and the environment up close.

“Don’t be scared,” the pilot barks at a reporter as the sub hits the edge of a sharp ledge and bounces off backwards into a murky crevasse. “It sounds bad but nothing’s gonna break.”

As the sub meanders along the bottom, a new kingdom slowly comes to life. Vivid pink and red stems of algae rising from the rough sand flutter eerily like lone, long-stemmed roses. Ivory-colored sponges decorate black craggy rocks.

Flounder swim lazily by the portholes. An enormous skate, lying flat along the bottom like a gray throw rug, heaves awake under the bright flood lights of the sub and circles the craft in apparent irritation.

The High School Aquanaut program is an opportunity for high school students and their teachers to participate in real undersea research in the Gulf of Maine, the waters off southern New England, the mid-Atlantic Bight and the Laurentian Great Lakes.

“I couldn’t believe what I was seeing,” said Mary Wohlleber, 17, who will be a freshman at Eastern Connecticut State University next year, and has made two dives. “It makes you appreciate the ocean more. You’re there doing the work firsthand and until you do it firsthand you don’t respect the animals or their environment.”

The program is sponsored by the federally-funded National Undersea Foundation at the University of Connecticut. At present, the students are from southeastern Connecticut high schools but there are plans to bring in inner-city students from New York next year.

“There’s no better way to get youngsters excited about the ocean and the environment than to make them diving scientists,” said Richard A. Cooper, director of the National Undersea Research Center.

It’s safe, too. The Delta has made 1,969 dives with no accidents. The sub is made of reinforced steel equipped with the same type of battery in a golf cart. It can go to 1,200 feet maximum without pressurized air.

Students in the program, now in its third year, take part in ongoing research experiments. They are selected on a competitive basis from their schools and plan their individual projects with their teachers and program coordinators before they go to sea.

“It was the experience of a lifetime,” 17-year-old Brad Martin said. “The views, the crew, being in a place that not many others are able to travel and explore. The program has been a dream come true.”

In the so-called Pigeon Hill area at Jeffrey’s Ledge off Gloucester, students help marine biologists measure the pollution content in scallops, which in turn determines the contaminant level in surface sediments. They deploy scallop cages on certain dives and later retrieve them with the aid of the mechanical arm of the Delta.

“We want to make them see that it takes only a short time to pollute the planet and several thousand years to reverse the process,” said Cooper.

The data gleaned from the scallop samples also has a larger significance, according to Bill Robinson, a marine biologist with the New England Aquarium and a program coordinator.

“We know more about corn in the Midwest than we do about fish in the ocean,” he said. “That’s why we can harvest corn so well. We don’t know anything about scallops but once we know about their reproduction cycles, it’ll make all the difference.”

Performer Richie Havens was aboard the research vessel J.W. Powell this week as it left Gloucester with a group of scientists and teachers to discover firsthand how the program works.

Havens, 49, who grew up in Brooklyn, works with underprivileged students in New York City in addition to his singing career. He helped found the Northwind Undersea Institute for children on City Island in the Bronx. He also heads the Natural Guard, based in Washington, D.C., a program which offers inner-city youth a chance to experience other environments.

“I was a city kid and city kids need a place to go away from the concrete,” said Havens, who will be bringing students into the program next year. “We’re trying to raise their consciousness about their environment by showing them something they wouldn’t otherwise see.”

Coordinators from the National Undersea Foundation hope the program will expand nationwide.