In a new study, researchers speculate that a towering undersea hot-water chimney laden with microbes is just the sort of place that might have spawned life on Earth or even other planets.

The hydrothermal vent system discovered two years ago has now been found to have endured for 30,000 years. Researchers said similar setups -- on Earth and possibly on other worlds -- might last millions of years and could have been incubators for the first life.

Underneath the structure, seawater seeps down into the fractured crust of Earth. There, the decay of one mineral forms another, called serpentine, and releases heat in the process. This process of serpentinization lifts warm water laden with minerals back into the ocean, building the structure.

Because the precious light and nutrients needed to support life are scant on the seafloor, hydrothermal vents are typically hubs of microbial activity.

The Lost City is potentially significant because it is the only known hydrothermal vent system that relies on chemical reactions to warm the water, not volcanic activity. The structure sits near but not on an area of volcanism.

If hydrothermal venting can occur without volcanism, the scientists involved in the study say, it greatly increases the number of locations on the seafloor of early Earth where microbial life could have started.

"It's difficult to know if life might have started as a result of one or both kinds of venting," said Deborah Kelley, a University of Washington oceanographer who worked on the study. "But chances are good that these systems were involved in sustaining life on and within the seafloor very early in Earth's history."

Scientists do not know how or where life on Earth began, however.

Kelly said there may have been many vents built from serpentinization on the early Earth, because the planet's mantle, now an inner layer, had yet to be covered over with crust, putting it in contact with seawater and making the process possible. For serpentinization to occur today, there must be fractures in the crust.

The 18-story system, which is about 30 feet (9 meters) wide, is similar to other hydrothermal vents in other ways. Water circulates beneath the seafloor, picking up heat and organic compounds and rising buoyantly back into the ocean. Warm fluids mix with cold seawater, chemicals separate from the vent fluids and solidify, and mounds, spires and chimneys of minerals are created.

Microbes love this stuff. Unlike plants, they don't need sunlight. Instead, vent microbes use chemicals, such as hydrogen sulfide or methane, for energy. Around some vent systems, larger life forms congregate and feed off the microbes.

Other vents that operate just like Lost City may exist and await discovery, the scientists say.

The newfound venting process might have occured on other planets, too.

The key material that interacts with seawater at Lost City is called peridotite, which is abundant on other planets in our solar system, said Jeff Karson, a geologist at Duke University.

"Peridotite can be exposed by tectonic processes or by major cratering events," he said. "This means that Lost City-type venting could occur, or has occurred, in oceans on other planets, and such venting would have the potential to support microbial systems."