The seven-arm octopus, Haliphron atlanticus, weighs as much as a person and haunts deep, dark waters from New Zealand to Brazil and British Columbia. So few people have seen this creature alive that researchers must study it in death—typically, as a mound of purplish flesh that washes ashore or turns up in a net. A living seven-arm octopus was scooped up by a Norwegian fishing trawler in 1984, but “when laid on deck the body collapsed,” a local zoologist wrote at the time. What remained of the creature, he added, was “sack-shaped, large and flappy.” Another turned up in a South Pacific research trawl in the early two-thousands, but the preservation process turned it into a “frozen lump,” the giant-squid expert Steve O’Shea wrote. When sea animals are too delicate to catch and keep intact, scientific accounts tend to feel as clinical and ghostly as the autopsies that they are. Researchers know next to nothing about how they actually live.
In October, 2018, against the odds, I saw a seven-arm octopus off the coast of San Diego, California. I was one of several deep-sea scientists aboard the research vessel Falkor, watching a live video feed as my colleagues joysticked a remotely operated vehicle, or R.O.V., along the seafloor. The footage, which was streaming live on the Internet, showed a bizarre and beautiful animal: a bundle of translucent tentacles that trailed like a cape behind a bulbous, purple head. (The species has eight arms, but one is often hidden.) Its almost-comical googly eye seemed to gaze back at the camera. We peeled the R.O.V. off its primary mission—a search for methane seeps on the seafloor—to follow the octopus.
We were captivated but also faced with a maddening dilemma. Do we leave the creature alone for a few precious minutes of passive observation, before it slips away? Or do we try to bring it back to the lab in one piece, and study its physiology as it withers in captivity? Trying to catch it with the R.O.V.’s robotic claw would be as clumsy as sewing while wearing mittens, likely to produce a stringy mess, so we decided to open a sample box and maneuver the car-size machine toward the octopus, a centimeter at a time. But we knew that the R.O.V.’s propellers could catch it in an eddy and churn it to bits.
I cringed as the R.O.V., like a car trying to overtake on a one-lane highway, lurched forward. The broadcast team cut to a different camera angle and muted our nervous conversations, in case the scene got ugly. When the R.O.V. briefly caught the octopus in its draft, we gasped, realizing how risky our efforts were. This was too much: we decided to bail. The experience forced us to admit that some of our most sophisticated scientific tools—such as R.O.V.s, which have explored swaths of the ocean with new clarity and precision—still risk destroying what we want to study.
Countless life-forms float, ethereal and gelatinous, between the sunlit shallows and the murky depths. Their daily migrations stir the ocean as much as wind or tides, and their falling corpses and waste feed life on the seafloor. But, because we lack the delicate technology to get to know them, we know vanishingly little about their behavior, their place in the food web, even their size and shape. Through the years, researchers have tried to engineer a softer touch—for example, with cages that fold underwater; foamy fingers controlled by hand-worn sensors; and futuristic, noodle-like strands that can cradle a creature—but even these innovations run the risk of reducing jellyfish to confetti. The very nature of these slippery creatures resists our advances; we can’t hold them lest we crush them in the embrace. How are you supposed to understand an animal that you can’t touch?
Kakani Katija, who leads the Bioinspiration Laboratory at the Monterey Bay Aquarium Research Institute (MBARI), originally set out to study space flight. She grew up in Portland, Oregon, and spent many evenings watching “Star Trek” reruns. She was enchanted by the show’s earnest spirit of exploration: the crew of the Starship Enterprise traversed the cosmos, “meeting aliens, and trying to communicate with them and learn from them,” Katija told me. By the time Katija entered a graduate program in aeronautics at Caltech, however, she was growing disillusioned with the private space industry. She studied with the bioengineer John Dabiri, who was researching how jellyfish move, in hopes of finding another career path. She understood that water moves around sea creatures in the same way that air flows around airplane wings, and she used an aerospace technique called particle image velocimetry, or P.I.V., to mathematically model both the water and the jellyfish. In 2009, her research showed how jellyfish and their soft-bodied relatives, dubbed gelata by the MBARI scientist Steven Haddock, collectively churn the ocean, like millions of spoons stirring in unison.
In 2014 Katija joined a research expedition on the R.V. Western Flyer with the ecologist Bruce Robison. (The ship is named for a fishing vessel made famous by the writer John Steinbeck.) When an R.O.V. moves through the water, its headlights cut through the darkness and turn it an eerie blue, like spotlights pointed at an empty stage. On the video feed that day, Katija saw a fist-size, glowing orb with a flicking tail, surrounded by a cloud of mucus the size of a billowing trash bag. The strange structure—even that word seemed too solid—was unlike anything Katija had seen. “Instantly, I had questions,” she recalled. “What is this thing? Just from a really basic standpoint, how does this thing exist?”
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Her colleagues told her that she was looking at a giant larvacean, Bathochordaeus stygius, which researchers had struggled to understand for decades. How did its body parts fit together, and why? What was the purpose of the netlike film that surrounded the animal? In the controlled setting of a laboratory, Katija might have reconstructed its anatomy by taking a high-speed video of particles flowing through and around the creature. But she could see that the giant larvacean would likely disintegrate if she tried to capture it. “I was kind of hooked on this idea that there’s so much we can learn about systems in the ocean if we could just observe and quantify them,” she said.
After the cruise, Katija got to work outfitting the Western Flyer’s R.O.V. with a one-watt laser system. She hoped to scan gelata in their natural habitat and teach computers to reconstruct their bodies. In 2015, she joined MBARI as a postdoctoral fellow and tested her system, which she calls Deep P.I.V., on giant larvaceans in Monterey Bay. It worked far better than she could have hoped for. The laser illuminated distinct planes of the translucent animals, and a high-resolution camera captured the scattered light. When the images were stacked in a 3-D model, Katija and her team could see the inner workings of these mysterious creatures. Like a 3-D printer operating in reverse, Deep P.I.V. was able to convert real-world shapes into a computational blueprint of the animal. Scientists could twist and turn the computer model with no danger of destroying delicate body parts.
Deep P.I.V. revealed that the netlike exterior excreted by a giant larvacean, which scientists call its house, filters out large particles that could clog the animal’s digestive system. The house emerges, fully formed, from the animal’s head, and inflates in the course of about an hour. At some point—the when and why remain a mystery—the larvacean discards it, to the delight of scavengers waiting on the seafloor below. Katija considers the house to be more sophisticated than the webs that spiders construct from silk strands. Larvaceans are “excreting a finished product—a structure that sits on top of their head, and then they blow it up like a balloon,” she told me. “It’s pretty incredible what these ‘simple’ animals are doing.” She wonders whether they could even inspire lightweight, inflatable modules in space.
Gelata may be a fundamental kind of underwater life. They evolved early and often in Earth’s history; they seem to drift effortlessly, in and of the ocean in a way that blurs the boundary between body and world. Other soft-bodied sea animals, such as octopuses and squid, evolved independently but seem to have converged on a similar anatomy. Yet scientists remain much better at studying animals that they can collect and dissect, such as the bony fish that appeared roughly two hundred and fifty million years after the earliest jellyfish. This leaves an enormous gap in our understanding of early sea animals and life in the mid-water, the vast region between the surface and the seafloor where many soft-bodied creatures thrive.
“It’s typically about ten years from the first time an animal is seen to an actual description of that species in a journal,” Katija told me. In a time of climate change and mass extinction, a decade can be long enough for a newly identified species to disappear. But scientists are accelerating the discovery process by studying sea creatures where they live, and by developing new ways to observe them. Last year, using only footage, a research team described a new type of comb jelly that lives in a deep-sea canyon north of Puerto Rico. The breakthrough was unprecedented, but also rather crude: scientists had to study the video “almost frame by frame,” squinting at pixels to count combs and trace the digestive tract, Allan Collins, who led the research for NOAA, told me. “We got a decent sense of it, but with something like Deep P.I.V. we would know a lot more,” he said.
Dhugal Lindsay, a research scientist with the Japan Agency for Marine-Earth Science and Technology, has been documenting the “mind-blowing” diversity of gelata for years. “We’ve tried X-rays, we’ve tried MRIs, we’ve tried CT scans,” Lindsay told me. “But, because there aren’t any hard parts in these gelatinous organisms, it’s hard to get 3-D information.” Katija’s approach turns the biggest challenge of gelata—they’re so thin and delicate that you can’t touch them—into an advantage: lasers can shine through them and illuminate their insides. “It’s really clever,” Lindsay told me. Katija’s team has used the same technique on sea sponges and swimming bells; perhaps one day lasers will shed light on the elusive seven-arm octopus.
The ocean is filled with alien beings, creatures that float rather than fall. In this sense, it’s no accident that Katija found, in the dark depths of the sea, a place to redirect her interest in outer space. To survey the unknown, scientists need new vantage points and new ways of seeing; a laser-equipped R.O.V. is a bit like a space telescope, collecting light from places we don’t yet understand. Katija’s next goal is to build an autonomous vehicle that could follow gelata for days, recording animals as they drift or swim. She hopes these images could reveal what the naturalist Jane Goodall saw in chimpanzees: behaviors and social dynamics that only sustained observation can capture. “We’re getting to know these organisms in a way we didn’t before,” Katija told me. “It’s like we’re really seeing them for the first time.”
