Off the west coast of Central and South America, there is a Lovecraftian, lava-licked realm thousands of feet beneath the ocean. There, on the seafloor, volcanically powered vents known as hydrothermal vents fire jets of water that reach temperatures of up to 700 degrees Fahrenheit. While the surfaces and surroundings of these vents have long been known to host a diverse mosaic of life, scientists have yet to identify the animals to find a home beneath these hellish geysers.
But that changed in July when a diving robot overturned volcanic bedrock marked by a hydrothermal vent and revealed an explosion of animal life – including many tubeworms, strange creatures that resemble sentient spaghetti.
“This is the first time that animal life has been found below the surface” of hydrothermal vents, said Monika Brightan ecologist at the University of Vienna and lead scientist on the expedition.
Microbe life was before known to exist within these hollows. But the idea that animals are locked inside vaults of volcanic rock, bathed in darkness, seems surprising. “The deeper you go, the hotter it is, the less oxygen, the more toxic chemicals it has,” said Dr. Bright. “It’s very shallow, but it’s still under the Earth’s crust.”
But not all experts were surprised by the discovery.
“I think it makes perfect sense,” said Julie Huber, a marine geochemist and microbiologist at the Woods Hole Oceanographic Institution in Massachusetts who was not involved in the work. “The shallow subseafloor, where temperatures are probably cold enough for animals to survive, I think of as a ‘subseafloor conveyor belt’ for microbes, nutrients and, now, animals.”
Most of these unusual habitats are a mystery. But, like many revelations found under the sea, this discovery once again pushes the boundaries of what scientists consider possible – perhaps even normal – for life on Earth.
hydrothermal vents, first discovered outside the Galápagos Islandsare Dalí-esque chimneys and chasms that often growing on or near midoceanic ridges — wide volcanic cracks in the seafloor caused by the divergence of two tectonic plates. Deep down, magmatic heat roasts seawater, returning it to the water column as superheated, mineral-rich soups.
Despite their extreme nature, these tunnels are metropolises of strange critters. Common among these are tubeworms, which begin life as free-swimming larvae before becoming sedentary adults that grow to several feet in length and feed on sulfur-eating bacteria living in their intestines.
Dr. suspected. Bright that these wiggly weirdos can also be found under the tunnels. “It was kind of a really fun idea that I had,” he said.
To find out — and to improve our understanding of the connections between life above and below hydrothermal vents — Dr. Bright is a team riding Falkor (also), a research ship owned by the Schmidt Ocean Institute. From June 27 to July 29, the researchers sailed to an eruption-prone part of the East Pacific Rise, a spreading seafloor schism that runs roughly parallel to South America.
There, they broke free SuBastian, a remotely operated vehicle with two armlike appendages to which drills, scoops and saws can be attached. It approached the bubbling tunnels, politely turned over some volcanic rocks and peered inside.
It exposed what geologists sometimes refer to as hollows — labyrinths of glassy rock cavities stretching in different directions, some decorated with arches and columns made of once-molten lava which is now frozen in time. Through these tunnels, water flows at a surprisingly temperate 75 degrees Fahrenheit. And every time the submersible looks inside these hidden geologic mazes, it sees animals, including huge numbers of adult tubeworms.
“They just grow there, live there,” said Dr. Bright. Snails, as well as various types of slithering worms, also flash.
The discovery raises new questions about deep-sea ecosystems. For example, are there relationships between the types of animal life and microbes found within the hollows? “I also can’t help but wonder if there are some life stages that are more commonly found under the sea, like larvae,” said Dr. Huber.
For some, this discovery gave rise to dreams of an otherworldly life. “I always think about ocean worlds when I study tunnels,” said Dr. Huber. Biological crucibles may exist within the icy seas covered by the carapace of Enceladus, a moon of Saturn that has the basic ingredients for life and that may also have hydrothermal vents on its seafloor.
But for Dr. Bright, only Earth matters. “I don’t think about other planets and moons – I think that there are so many mysteries to be discovered on our Earth,” he said. “I feel like I know this place. I have studied in this place for 30 years. And yet, you will find something unexpected.”