Experts aboard the RRS James Cook said they found the vent more than three miles (five kilometers) beneath the surface of the Caribbean in an area known as the Cayman Trough, a deep-sea canyon that served as the setting for James Cameron's underwater thriller "The Abyss."
Volcanic vents are networks of small cracks that penetrate deep into the earth's crust, where temperatures can reach 750 degrees Fahrenheit (400 degrees Celsius). Sea water seeps into the openings, where it's heated to extreme temperatures and expelled into the icy cold of the deep ocean. Minerals in the water precipitate as it cools, creating a smoke-like effect and leaving behind towering chimneys. The spectacular pressure - 500 times stronger than the earth's atmosphere - keeps the water from boiling.
Geologist Bramley Murton, the submersible's pilot, said the exploring the area was "like wandering across the surface of another world," one complete with towers of mineral deposits and thick collections of microorganisms thriving in the slightly cooler waters around the chimneys.
"The rainbow hues of the mineral spires and the fluorescent blues of the microbial mats covering them were like nothing I had ever seen before," Murton said.
Scientists exploring other vents have discovered host lush colonies of exotic animals such as hairy worms, blind shrimp and giant white crabs.
"The deep sea is full of surprises," a statement posted to the expedition's Web site said. "We may find species unlike any seen before."
Other scientists said they were excited by the find.
"I'm extremely curious to see and hear what they have found there in terms of biology," said Maya Tolstoy, a marine geophysicist with the department of earth sciences at Columbia University.
This vent and others like it are also of interest to scientists because of the role some scientists believe they played in the creation of life on earth.
Research project leader Jon Copley said it has been theorized that life may have originated in similar environments early in the Earth's history - in part because the microorganisms found in deep-sea vents appear close to some of the Earth's most ancient organisms.
Still, Copley said, "there are a lot of assumptions in that deduction."
"The origins of life is one of the greatest unanswered questions in science, and at the moment vents are one of the contenders, but they are certainly not the only one."
The Cayman Trough vent was discovered on April 6, according to Copley, who said the team used a cube-shaped submersible about 6 feet on each side and linked to the ship by three miles (five kilometers) of cable. Copley said the discovery had been three years in the making and built on the previous efforts to scour the depths for signs of the cloudy, mineral-laden water which the vents emit.
He said the find illustrated how little was known about what lurks at the bottom of the sea, a sentiment backed by Tolstoy.
"We know more about the surface of the Moon and Mars than we do about our own planet because two-thirds of our planet is covered by ocean making it very hard to explore," she said.
"We've only seen a tiny fraction of the deep sea floor so there are undoubtedly many more vents and other amazing things to discover."