Giant tubeworms part of thriving ecosystem found under the seafloor in the Pacific

Researchers have found a thriving ecosystem of animal life in an unlikely place: beneath hydrothermal vents under the seafloor of the Pacific Ocean.

A community of marine life was found below the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor, according to a paper published Tuesday in Nature Communications.

"It was once believed that only microbes and viruses inhabited the subseafloor crust beneath hydrothermal vents," the study states.

But, living organisms such as giant tubeworms, worms and snails were found in hydrothermal vents, which are openings on the seafloor that form where seawater and magma beneath the Earth's crust meet, Monika Bright, a marine ecologist at the University of Vienna and co-author of the paper, told ABC News. Previously, these species -- and others, such as mussels -- were only found on the seafloor near these vents, the researcher said.

Researchers used a remotely operated vehicle equipped with a chisel to drill holes through about 10 centimeters of basalt, or volcanic rock, where they expected larvae for these organisms were settling, Bright said.

Instead, they found an empty space that, after lifting the rock and flipping it over, they realized contained an entire community of living animals, including giant tubeworms, within the small cavities.

"There were animals, 50 centimeters long, lying in there -- alive," she said.

The discovery was "spectacular," Bright said, adding that there is a large area of unknown space that potentially extends the habitat of those species.

The research suggests that larvae from seafloor communities may settle into habitats below the seafloor after getting "sucked" into the Earth's crust with the seawater amid the hydrothermal circulation system.

"We have many, many areas where seawater is getting into the Earth's crust and then mixes in the crust with hydrothermal vent fluid," Bright said.

The extent to which animals live in the crustal subseafloor is currently unknown, increasing the urgent need for protections against future environmental changes, research suggests.

However, it takes "a lot of money" to conduct deep-sea research, Bright said.

"The ocean plays a very big role for our planet, for our climate, and therefore ... we need to study it better," she said. "I'm very sure that there are many more discoveries to come, even when it's very expensive and difficult to work in these deep sea environments."

Only about 5% of the world's oceans have been explored, according to the National Oceanic and Atmospheric Administration.

New species are being discovered all the time, marine experts say.

"Every time we go out to the ocean, we find something new," Jyotika Virmani, executive director of the Schmidt Ocean Institute, told ABC News in August.