Pictures Reveal One of the Last Unexplored Places on Earth

Diving miles beneath the sea, an ROV finds a new type of volcanic vent teeming with life near the Mariana Trench.

More than 3,900 metres under the sea, scientists have found a volcanic wonderland unlike any other place on Earth.

The newfound ecosystem is crawling with life—hairy snails, ghostly shrimp, and weird worms—including some species that may be new to science.

The discovery involves three new hydrothermal vents that exist along the Mariana Back-Arc, a dynamic zone between Papua New Guinea and Japan where new ocean crust is constantly bursting forth. The Back-Arc is part of an active geologic region that includes the Mariana Trench, the deepest place on Earth.

Finding the new vents was “a big breakthrough, a big thrill for everyone,” says team member William Chadwick, a submarine volcanologist with the U.S. National Oceanic and Atmospheric Administration.

“There’s a lot to learn about these habitats—not only the neat animals, but how they fit into the global picture,” says Andrew Thurber, a deep-sea ecologist at Oregon State University who was not part of the expedition team.

“This particular [site] is pretty different than those often studied, so it’ll add to our overall understanding of the global ecosystem.”

The three vents were crawling with crabs, shrimp, and other types of life, including some species that may be new to science.

Enter The Luck Dragon

Scientists found the vents thanks to SuBastian, a new kind of remotely operated vehicle developed at the Schmidt Ocean Institute in Palo Alto, California.

Guided from the surface by the Schmidt research vessel Falkor, the remotely operated vehicle can stay underwater for weeks at a time.

The Falkor did an initial investigation of the Back-Arc in 2015, but that expedition didn’t have SuBastian. Scientists on that trip instead observed what looked like vents and active lava flows using remote sensors, and then marked the approximate locations on a map for future study.

The ROV SuBastian prepares to take a sample from one of the newfound deep-sea vents.

“It’s like if we were in a helicopter looking for which house in a neighbourhood had their fireplace on, and we’re lowering sensors to look for smoke coming out of a chimney,” says Chadwick.

That meant there was no guarantee the SuBastian team would be able to find the vents again. But during a three-week expedition in December, luck was on their side: The team located the three chimneys on their very first dive with the ROV.

On that dive, SuBastian flew into a live underwater volcano and was engulfed in smoke. Its bottom half and entire front portion were coated in lava as the volcano erupted.

The rover glimpsed snails and shrimp through the dark, chemical-rich plumes pouring out of the hydrothermal vents.

“We came to a point where droplets of molten sulphur were spitting up, and we realised we needed to get the hell out of there,” says lead mechanical engineer Jason Williams. “So that was obviously a little stressful—and exciting.”

The ROV was not damaged. The bottom of the ocean is very cold, and though sulphur spews out from the chimneys at up to 690 degrees Fahrenheit, it cools almost instantly.

Finding Fantasia

Over the next couple weeks, the team conducted their research in 12-hour dives, getting up before dawn each day to prep the rover and send it on its two-hour commute to the bottom of the Back-Arc.

When the rover came back to the surface laden with samples, the scientists streamed out of the control room and descended upon its bounty. They spent evenings in the lab processing what was collected, while the rover team started getting SuBastian ready for the next day’s dive.

“It’s a long day each day,” says Chadwick. “It’s a bit exhausting. We stagger the hours so the people who were up late can sleep a little, and the others can run things in the early hours.”

Scientists and engineers gather in the control room on board the Falkor to watch the ROV in action.

Hydrothermal vents are epicentres of diversity in the deep sea. Since much of the ocean floor is mud, the sudden presence of hard rock provides attachment points for corals and sponges, which in turn changes the dynamic of life in the immediate vicinity.

Vents also provide another crucial resource for evolving organisms: heat. These vents churn out up to 3 percent of the total energy in the deep sea.

The newly discovered vents are especially unusual, because they resemble no other known environment on Earth—except each other.

Though their physical topography differs in size, layout, and other superficial features, the chimneys at all three sites display a remarkably similar chemical makeup even though they’re each up to a hundred miles apart.

“Not all vents function the same, they don’t all have the same temperature or release the same chemicals,” says Thurber. “That leads to different sorts of animals.” Studying their genetic makeup may one day reveal new avenues for diverse applications, from medicine to household products.

“All these crazy critters—this expedition definitely got to see lots of cool animals endemic to these vents,” adds Thurber.

Once the ROV returned, scientists would spend hours each day analysing samples brought up from the vents.

Neverending Story

Now that the expedition is over, the scientists will take the data and samples to dozens of collaborators back on land. The snails might be sent to someone in Sweden; the shrimp may go to someone in Australia.

It’ll take a year or two to really sift through everything and figure out whether they have any new species or other surprises. In the meantime, the scientists will give the ROV team input for potential ways to improve SuBastian for future dives.

Another Falkor trip is already on the books to return to the Back-Arc later this year. After all, the majority of the region—more than 370 miles of it—remains unexplored.

“That’s kind of the fun thing about going to new sites,” Chadwick says. “There’s a good chance of finding new things nobody’s ever seen before.”

Header image: The team recovers the ROV at the end of a long day's dive. PHOTOGRAPH BY THOM HOFFMAN, SCHMIDT OCEAN INSTITUTE

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