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Animals that live underground near deep-sea hydrothermal vents

Animals that live underground near deep-sea hydrothermal vents

The research vessel Falkor can also be seen at sunrise in the Pacific Ocean, working above the Tica Vent on the East Pacific Rise at a depth of 2,500 meters. CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
Photo of hydrothermal ventsPhoto of hydrothermal vents
An upside-down rock crust sample reveals Oasisia and Riftia tubeworms and other organisms as it is examined after being recovered from beneath the Pacific Ocean floor above the East Pacific Rise, a volcanically active ridge that lies where two tectonic plates meet The seabed in this undated photo. CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
In this undated photo, giant tubeworms are seen in a shallow subsurface cavity beneath deep-sea hydrothermal vents on the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean. CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
Giant tubeworms on the seafloor surface in 2,500 meters of water on the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean, in this undated photo.CC BY-NC-SA Schmidt Ocean Institute /Handout via REUTERS
By Will Dunham | REUTERS

A deep-diving robot that carved into the rocky ocean floor of the Pacific at a spot where two of the giant plates that make up Earth’s outer shell meet has uncovered a previously unknown realm of animal life living underground in thrives near hydrothermal vents.

The remote-controlled underwater vehicle SuBastian was used to find giant tubeworms – the heaviest worms in the world – and other marine invertebrates such as snails and bristleworms. They lived in cavities in the Earth’s crust on the ocean floor, where the Pacific Ocean is 1.56 miles (2,515 meters) deep. Previously, all species were known to live near such springs, but never underground.

“We discovered the life of squid animals in the cavities of the ocean crust. “We now know that the unique ecosystem of hydrothermal vents extends into the ocean crust,” said marine biologist Sabine Gollner of the Royal Netherlands Institute for Marine Research, one of the leaders of the study published this week in the journal Nature Communications.

“To our knowledge, this is the first time that animal life has been discovered in the ocean crust,” added Gollner.

The exploration was conducted on the East Pacific Rise, a volcanically active ridge on the floor of the southeastern Pacific Ocean that runs roughly parallel to the west coast of South America. The rigid outer part of the Earth is divided into colossal plates that gradually move over time in a process called plate tectonics. The East Pacific Rise is where two of these plates gradually drift apart.

This area contains many hydrothermal vents, cracks in the ocean floor where seawater and magma come together beneath the Earth’s crust. Magma refers to molten rock that is found underground, while lava refers to molten rock that reaches the surface, including the ocean floor. New seafloor forms where magma is pushed to the surface along a mid-ocean ridge and cools to form volcanic rock.

The hydrothermal vents spew the superheated and chemical-rich water into the cold sea, which nourishes microorganisms.

“The warm vent fluids are rich in energy – sulfide, for example – that can be used by microbes that form the basis of the food chain,” Gollner said.

Life thrives around the vents – including giant tubeworms that reach 10 feet (3 meters) in length, mussels, crabs, shrimp, fish and other organisms that have adapted beautifully to this extreme environment. The giant tube worms do not eat like other animals. Instead, bacteria located in a sac-like organ in its body convert sulfur from the water into energy for the animal.

The researchers deployed SuBastian from the Schmidt Ocean Institute’s research vessel Falkortoo to the vent site deep down. The robot was equipped with arms that wielded a chisel, which the researchers used to dig into the crust, revealing warm and fluid-filled cavities where tubeworms, bristleworms and snails were spotted.

“We smashed the stone with a chisel. We dug about 20cm (8 inches). The lava slabs were about 10 cm (4 inches) thick. “The cavities under the lava plates were about 10 cm high,” said Gollner.

Larvae of these animals can invade these subseafloor habitats, the researchers said, and are an example of the connection between the seafloor and subterranean ecosystems.

“It changed the way we look at connectivity in the ocean,” Gollner said of the discovery of the underground lair.

Editor’s note: Reporting by Will Dunham, Editing by Rosalba O’Brien

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