An octopus hatchling emerges from a group of eggs at a new octopus nursery, first discovered in June at the Tengosed Seamount off Costa Rica. ROV SuBastian/Schmidt Ocean Institute

The tension was building inside the ship’s control room, where researchers crowded around a screen to watch a remotely operated vehicle move across the seafloor 2 miles below.

As the vehicle, or ROV, moved along the south-facing slope of El Dorado Hill, a rocky outcrop in the Pacific Ocean off Costa Rica, an octopus hatchery came into view. Brooding mothers nestled against the rocks, tentacles and suckers facing out to ward off predators.

The scientists watched as a pale pink octopus emerged from a cluster of potato-shaped eggs and swam away into the dark deep sea. A parade of hatchlings soon followed.

“It’s a baby!” exclaimed Dr. Beth Orcutt, a geomicrobiologist and vice president for research at Bigelow Laboratory for Ocean Science in East Boothbay. Orcutt co-led the research expeditions last June and December that resulted in the discovery of at least four new species of deep-sea octopus, two of which brood their eggs in hydrothermal springs on the seafloor.

The moment was a decade in the making for Orcutt, who first glimpsed the hatchery during a previous research expedition. It was the first grouping of its kind ever found – most octopuses tend to their eggs alone – but at the time, the eggs lacked signs of life, such as visible eyes. Scientists who study the deep-sea and octopus were eager to go back to learn more.

Dr. Beth Orcutt, of the Bigelow Laboratory for Ocean Sciences, led a research expedition to the Pacific Ocean off the coast of Costa Rica last year that led to the discovery of four new species of octopus that brood around the hydrothermal vents on seamounts. Shawn Patrick Ouellette/Staff Photographer

The team of researchers from the United States and Costa Rica returned to the area during two expeditions last year. The research vessel, called Falkor (too) in honor of the character from “The Neverending Story,” became their home base. Using an ROV they controlled from the ship, they explored deep below the Pacific Ocean’s surface and discovered three hydrothermal springs in the region.

They found two octopus nurseries during their first trip in June. Six months later, they returned to the area and confirmed the nurseries are active year-round. The team also found two new octopus species away from the hydrothermal springs.

The team found a thriving deep-sea skate nursery at the top of the Tengosed seamount off Costa Rica, nicknaming the site “Skate Park.” ROV SuBastian / Schmidt Ocean Institute

Another unexpected find was a thriving deep-sea skate nursery at the top of another seamount that they nicknamed “Skate Park.” Sea skates are flat-bodied, bottom-dwelling fish.

All of the discoveries help scientists better understand the deep sea, very little of which has been studied.

“The impact of the R/V Falkor (too) expeditions on understanding the deep Pacific waters off Costa Rica will last into the future and hopefully create awareness that evolves into policies to protect the deep sea of the country,” said Jorge Cortés of the University of Costa Rica, who led the expeditions with Orcutt. “I hope that the expedition serves as an inspiration for new generations. We need more international collaborations to advance knowledge of our deep-sea heritage.”

DEEP-SEA EXPEDITIONS

Orcutt has spent her career studying microbes, or microscopic organisms that are too small to be seen with the naked eye. She says she’s fascinated by all the “weird chemistry” they perform in the environment, especially the deep sea. About 10 years ago, she was part of a team of scientists looking for hydrothermal springs in the seafloor off Costa Rica.

They were interested in the springs because they are important for global chemical cycling and the ventilation of heat from the earth, she said. Orcutt was especially interested to see if unique microbes were living there. Hydrothermal springs are around 56 degrees Fahrenheit, a little warmer than the ocean temperature, which is about the same as a refrigerator at a depth of 2 miles, Orcutt said.

During that trip, Orcutt and two others used a small submersible vehicle – it was 6 feet in diameter and only big enough for three people to fit inside – to travel an hour and a half down to the seafloor.

“When you’re at the bottom, it’s like being on another planet. That’s the only way I can describe it,” she said. “It just looks so weird and alien and beautiful.”

As they searched for hydrothermal springs, the scientists thought they might find venting black smokers, chimney-like structures that emit a cloud of black material and water from below the Earth’s crust that can reach more than 700 degrees.

What they found instead were octopuses, Orcutt said.

Brooding mother octopuses often curl themselves up, with tentacles and suckers facing out. Researchers believe this to be a defensive position, warning predators off. When a female octopus broods (which can be a timespan of multiple years) she does not eat and dies around the same time her eggs hatch. ROV SuBastian / Schmidt Ocean Institute

“At that time we didn’t have any biologists on the ship with us, so we didn’t appreciate how weird that was,” she said. “It turns out the octopus were basically sitting in the cracks in the rocks where the water was weeping out of the seafloor.”

Janet Voight, an octopus expert who works at the Field Museum in Chicago, heard about the expedition and was eager to look at photos and video. She and two colleagues then published a paper in 2018 about the first deep-sea octopus hatchery and the 100 octopuses discovered brooding 3,000 meters deep on the Dorado Outcrop.

They concluded the octopuses Orcutt spotted were doomed because the water was too warm and there wasn’t enough oxygen.

Fiorella Vasquez, a researcher at the University of Costa Rica, processes a deep-sea octopus sample in the main laboratory during the expedition off Costa Rica. Conor Ashleigh/ Schmidt Ocean Institute

But Orcutt couldn’t get the findings out of her mind.

In the years since that first trip, there has been a growing interest globally in commercial deep-sea mining, which aims to retrieve valuable mineral deposits from the ocean floor. Those materials are needed to build zero-carbon energy components and other technologies. Exploratory mining has already started.

The United Nations International Seabed Authority has until 2025 to finalize regulations that will dictate whether and how countries can pursue deep-sea mining in international waters, where the bulk of the materials are found.

As Orcutt thought about what environments in the deep sea need to be protected from mining, she said she got curious about going back to Costa Rica and “really trying to figure out what was going on with the octopus.”

She teamed up with scientists in Costa Rica and secured funding from the Schmidt Ocean Institute to use its Falkor (too) for the 2023 expeditions.

A mother octopus broods her eggs near a small outcrop of rock unofficially called El Dorado Hill. The Dorado octopus is one of the newly identified octopus species found during the expedition. ROV SuBastian / Schmidt Ocean Institute

A ‘CHONKY’ OCTOPUS

This time, the team got a much closer look at the octopus hatchery and saw one new species of Muusoctopus, now nicknamed the Dorado octopus, brooding eggs at the hydrothermal springs.

The Dorado octopus is a related but distinct species from the Pearl octopus found on a seamount in California in 2018. The discovery of the Dorado adds evidence that the Muusoctopus genus has evolved to brood eggs in warm springs.

The newly discovered species has slightly different features, including the length of its arms and the ratio of the arm length to its mantle. It’s about the size of a computer keyboard – roughly a foot and a half long, Voight said. It’s also bulkier than other octopus species.

“You think about octopus being kind of svelte. The shallow-water octopuses have narrow heads, they get in between rocks and coral reefs. They’re pretty sleek animals,” she said. “Not these guys. They’re chonky.”

A new octopus hatchling swims away from its egg near a small outcrop of rock unofficially called El Dorado Hill. ROV SuBastian/Schmidt Ocean Institute

Voight was in the control room watching as the hatchlings emerged from their eggs and used spaghetti-like legs to swim away. It was thrilling to see, she said, even though it proved the findings of the 2018 paper were wrong.

Researchers were able to collect specimens of the Dorado octopus and three other new species. Two of the species found away from the vents have traits similar to medium-sized octopuses from the Muusoctopus genus, with two rows of suckers on long arms and bigger eyes than the Dorado. The fourth species has bumpy, pale skin and a single row of suckers on each arm.

Orcutt said the team believes there are two other new species down there, but they weren’t able to get specimens and can’t do a full description of the species.

“That’s a remarkable level of diversity of octopus in one area,” Orcutt said.

This sighting of glass octopuses was unusual. Researchers are not sure if it is an act of predation or copulation, as it appears to be multiple octopuses intertwined. Glass octopuses are nearly completely see-through, excellent camouflage that gives them an advantage against both predators and prey. ROV SuBastian / Schmidt Ocean Institute

Voight is now working with Fiorella Vasquez from the Zoological Museum at the University of Costa Rica to describe the new species, a process that includes carefully detailing all aspects of the octopus. They also will sequence DNA from the specimen to compare to other octopus species.

There are still lots of unanswered questions and areas to explore, and the scientists are eager to continue their research.

“I hope that the kind of research that we are doing, and just showing the incredible and amazing animals that we find in the deep sea, inspire people to think what might we lose if deep-sea mining causes impacts we are not prepared for,” Orcutt said.