Scientists discover surprising animal ecosystem thriving under the seafloor

Scientists probing the bottom of the Pacific Ocean made a surprising discovery: animals living underneath the seafloor in an area with volcanic activity.

Giant tubeworms, which are known as the world's heftiest worms and can grow to several feet long, are living with snails and other worms underneath the shallow seafloor crust in an area known as the East Pacific Rise.

They were discovered when a deep-diving, remotely operated vehicle dug into sections of the crust where two tectonic plates meet and there are hydrothermal vents, which are like hot springs on the ocean's floor.

Before this discovery, which was published on Tuesday in the Nature Communications journal, it was thought that only microbes and viruses could live beneath the crust and between the hydrothermal vents. Researchers previously knew that giant tubeworms and other creatures lived on the seafloor.

"To our knowledge, it is the first time that animal life has been discovered in the ocean crust," marine biologist Sabine Gollner of the Royal Netherlands Institute for Sea Research said.

A whole new world: Surprising ecosystem thriving under sea floor

The study authors found the tubeworms and other species living in warm, fluid-filled cavities more than 2,500 meters, or 1.5 miles, deep.

"We now know that the unique hydrothermal vent ecosystem extends into the ocean's crust," Gollner said. "It changed our view on connectedness in the ocean."

The discovery sheds new light on the relationship between the seafloor and underground ecosystems, the researchers said. It suggests that larvae from the animals on the seafloor may settle into the subseafloor habitats.

"Rapid colonization by these animals suggests efficient larval dispersal, with larvae assumed to be transported through bottom, ridge and ocean currents before they settle at vents through downwards swimming or sinking," the researchers wrote.

The tubeworms, with the scientific name Riftia pachyptila , can be found in colonies near hot, mineral-rich water and don't eat – bacteria in their system transforms sulfur into energy instead, according to the Monterey Bay Aquarium Research Institute.

Discovery underscores need to protect against environmental changes

The researchers said the extent of animal habitats on the subseafloor is unknown, but this discovery could benefit understanding of hydrothermal vent communities and global biological diversity.

"The study of the subseafloor biosphere for animal life has just begun," they wrote.

They said the discovery increases the "urgency" of protecting the hydrothermal vent ecosystems from human impact, including deep-sea mining.

Contributing: Reuters

This article originally appeared on USA TODAY: Scientists discover surprising animal ecosystem thriving under the seafloor