While traversing the seafloor in a pressurized bubble 3,200 feet beneath the ocean, marine photographer Gavin Thurston spotted an odd creature, about the size of a football.
"It looked like a mix of four animals," said Thurston.
He shone a light on it, for a better view.
"Clearly this beasty -- whatever it was -- didn’t like the light," he said, and it danced away on its silken thread-like legs, out of the glow.
It appeared to be a sponge, but covered in siphons, like pistons in a car engine thrusting up and down. It wore a crown of tentacles, which grabbed tiny critters out of the water.
Back on the surface, Thurston showed the images to marine scientists. "They didn't know what it was," he said. So, they emailed the photos out to other scientists. The answers were all the same: "No idea."
These ocean depths remain largely mysterious because they're hard to reach, and we have explored relatively little of them.
OceanX, launched June 5, however, has plans to change this by taking its exploration vessel and deep sea submersibles to never-visited places. The aim is to bring footage of uncharted regions back up to the surface, for us land-dwellers to see and understand.
The organization brought its vessel, the Alucia, to remote ocean worlds to shoot footage for the BBC's Blue Planet II series. Two new videos from OceanX Media and BBC Earth's Our Blue Planet initiative detail how photographers Gavin Thurston and Hugh Miller capture little-seen natural beauty in these uncharted realms.
Diving in ice
In one of the videos, seen above, Hugh Miller dives down 75 feet beside an Antarctic iceberg, in a region off the continental arm that extends towards South America.
"We had to choose the iceberg carefully," said Miller, in an interview, noting that the massive, creaking chunks of ice catch the wind and go sailing.
Looking down into the black depths beside the wall of ice, "I do remember feeling quite a strong sense of vertigo," said Miller.
"I do remember feeling quite a strong sense of vertigo"
In such frigid waters, this dive lasted about an hour. But it's not because Miller ran out of air.
"Generally you just get too cold," said Miller, who wears at least four thermal layers under his dry suit. "It's about how long you can endure."
Wildlife, like penguins and seals, are abundant in these remote waters. Miller treads gently in the water, attempting to be as benign as possible.
"They won’t perceive you as a threat and carry on with their lives," he said.
Seals were curious about Miller's dark, camera-wielding presence in the water, and swam towards him for a closer inspection. But not the penguins.
"The penguins don’t want to come near you," he said. "In the water, a six-foot animal to them looks like a leopard seal, so they’re not keen on hanging around."
Thousands of feet under the sea
The second video, below, shows marine photographer Gavin Thurston descending into the lightless deep sea. Here, coming across bizarre creatures, like a curious squid or two, is normal.
Whenever you're standing on a boat, said Thurston, "just a kilometer beneath your feet are things humans have never seen."
Thurston descended around 75 times, spending an average of eight hours in the deep sea submersible with a pilot and scientist.
Some might think needing to use the bathroom would be the limiting factor, but it's not. Although, Thurston did admit that he once had a cup of tea before a deep sea dive, and "tempted fate."
Rather, they were forced to return when the submarine's carbon dioxide scrubber filled up, and couldn't filter out anymore more of their exhaled breath.
The submersibles are profoundly quiet, unobtrusive machines, which is ideal for not scaring any critters away. "It's just like a big jellyfish, really." In fact, Thurston said the loudest thing down there are their own voices, which carry through the 5-inch thick plexiglass bubble -- so they need to speak quietly.
A massive swordfish once visited the submarine, investigating the strange yellow machine. It's a unique feeling to have large undersea creatures come and stare at you, said Thurston.
"You’re in the most amazing aquarium -- except you’re the one captive," he said.
