Then one of them gasped. "There's a baby, there's a baby!" she cried.
The tiny newborn, its body a light translucent pink, reached out with all eight tentacles and propelled itself upward.
"That was just an incredible moment," said Beth Orcutt, who led the research project to the Pacific Ocean’s Dorado Outcrop site in June with Jorge Cortes of the University of Costa Rica. "The mission control room got very crowded and very noisy."
There was much to celebrate: The 18-person team had just discovered the fourth known deep-sea octopus nursery in the world—as well as possibly a new species. The other three nurseries exist off Canada, California, and Costa Rica, just 30 nautical miles from Dorado. (Read about the deep-sea nursery found in California.)
"Finding a nursery is a significant event for understanding where there are unique places of biodiversity in Costa Rica's waters that might be worthy of attention," says Orcutt, senior research scientist at the Bigelow Laboratory for Ocean Sciences in Maine.
Many octopuses are solitary creatures that attach their eggs to hard surfaces, then brood and protect their developing babies from predators. Mothers regularly blow water on the eggs to oxygenate them and prevent algae and fungi from taking over, says Jennifer Mather, an octopus expert at the University of Lethbridge in Canada who wasn't part of the expedition.
Once the eggs hatch, the juveniles swim away to start a new life, and the mother typically dies, Mather says. (Why octopus moms are the ultimate examples of self-sacrifice.)
But things look a little different in the Dorado Outcrop, a rocky area about 10,000 feet deep. The ROV filmed many brooding octopuses crowded in the same area, even more than in 2013, when Orcutt last visited the site.
"The very first thing we could see on our very first dive was that there were even more octopus[es] in the same spot. So that got us really excited," she says. "It's almost like a population explosion."
Why the social gathering? Octopuses need hard surfaces to lay their eggs, but the deep ocean is mostly soft and squishy mud, without many rocks.
"They're only nurseries by accident," Mather says.
“It does not surprise me that four of these areas have been discovered, as rocky spaces down deep must be at a premium.”
New species of the deep?
The Dorado hosts a collection of hydrothermal vents that spew warm water and are likely also attracting octopus moms. Orcutt theorizes this warmer water may benefit the eggs, as well as possibly help mothers brood more quickly.
These animals are impressive in their ability to live in a high-pressure, low-temperature, and pitch-black environment—not to mention sharing their space with other octopuses, she says. (Learn why octopuses remind us so much of ourselves.)
The team likely observed three different species over the course of the 19-day expedition, and one is a potentially new member of the genus Muusoctopus. It will take additional research, such as capturing a specimen and testing its DNA, to know for sure, Orcutt says.
It doesn’t surprise Mather that the octopus could be new to science, considering how much there is to learn about them.
“Over 99 percent of mammals have been discovered and named, but for mollusks, including cephalopods, it’s around 50 percent.”
‘More exploring is needed’
The nurseries aren't all that the team found.
The Octopus Odyssey team visited five unexplored seamounts, undersea mountains that are also home to hydrothermal vents.
"All of them seemed to be different in terms of their dominant animal species," says Orcutt. One was covered in sea cucumbers, while another featured a bunch of black corals. The team also saw embryos of skates, a type of fish related to sharks, lying near the hydrothermal vents. (Read how the Pacific white skate lays its eggs on hydrothermal vents.)
But there’s much more to find. Orcutt estimates that although around 30 percent of the seafloor has been mapped, humans have only surveyed closer to one percent.
"There's a lot out there that we haven't seen, that we don't know in terms of biodiversity. More exploring is needed."