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This article was originally published in bioGraphic, an independent journal on nature and conservation promoted by the California Academy of Sciences.
The nautilus inhabited the deep waters surrounding the forested island of Manus, an exclamation mark at the northwestern tip of Papua New Guinea’s Bismarck Archipelago.
He lived slowly and in almost total darkness: his large eyes tuned to the blue wavelengths of bioluminescent bacteria that indicated a carcass to search, and sensitive enough to distinguish night from day 300 meters below the surface. His 90 tentacles and superlative sense of smell helped his search for food on the seabed. And as he grew older, he added new chambers to his spiral shell.
When the nautilus died, perhaps at the age of 20 or 30, its soft, squid-like body rotted. Its shell lost the neutral buoyancy that allowed it to sail effortlessly to any depth you chose, and floated to the surface. The currents dragged him to the mangroves, or to one of the palm-fringed beaches of Manus, or perhaps to a nearby coral atoll, called Ndrova Island.
Where it landed, the elegant cream spiral of the rust-brown striped shell would have caught the woman’s attention as she searched for seafood. He took her home, made her useful.
Manuai Matawai grew up seeing her mother, like the other women in her fishing village, use the sealed outer chamber of the nautical shell as a spoon to separate the fragrant coconut oil from the fruit starch at the bottom of the shell. his pot. The nautilus, called kalopeu in the local language of Titan, was also the symbol of a prophet that Matawai followed. But like most of his coastal community, he had never seen any alive, due to his preference for cold, dark depths.
Then, in 2015, he had his chance. Researchers from Australia and the United States came to study the creature, and Matawai, then working for the Nature Conservancy (TNC), helped organize his expedition to Ndrova. Peter Ward, a paleobiologist at the University of Washington widely known as the “Professor Nautilus,” had last visited him in 1984, when he and a collaborator were among the first to examine a living fuzzy nautilus, a species belonging to a new genus that they later called Allonautilus scrobiculatus. Ward and his colleagues had returned to see if the diffuse nautilus and the better-known chambered nautilus (Nautilus pompilius) were still there, and to test some new research tools.
From the left, Pomat Kanawi, Gregory Barord, Peter Ward and Manuai Matawai snorkel on the island of Ndrova, Papua New Guinea, in search of little-understood and little-seen nautilus. Photo of Manuai Matawai
Only a handful of scientists study nautical, and many of the most basic questions about the life of creatures have not been resolved. However, they have captivated humans for centuries, their shape has inspired the art, architecture and mathematics of many cultures. The 20,000-league submarine was called the Nautilus, as was the first nuclear submarine. Today, many companies, from wineries to exercise machine manufacturers, also use the name.
“I don’t know if it’s the most mysterious animal known or the most mysterious animal known,” says Gregory Barord, who joined Ward’s 2015 expedition. Scientists hoped to dispel some of this mystery through their research in Ndrova, but what they found provoked even more questions.
Shortly after Ward put on his diving gear and descended the steep cliff walls, he noticed the change. By 1984, scientists had been chased by sharks. “They were nasty, grumpy little bastards, so I was afraid to go through it again,” Ward recalls. But this time, they saw none, suggesting a change in the ecosystem. There was also evidence of coral bleaching, and the waters that had been pleasantly cool under the shallow depths now felt uncomfortably warm.
The experiment inspired Ward to pursue a new line of research, analyzing the composition of nautilus shells to monitor climbing temperatures in the depths of the sea and looking for the behavior of nautilus to predict how these changes might affect their beloved subjects of study.
Climate change is drastically altering ocean life around the world, and now extreme heat is normal in many places. Ward believes nautilus may already be seeking refuge in cooler, deeper waters to cope. But only so far will mollusks be able to swim. Below 800 meters, the pressure is enough to make their shells implode.
A store in the Philippines sells piles of spiral shells from a large container. More than 100,000 nautilus shells were imported into the United States alone between 2005 and 2014. Photo by Greg Barord
At the same time, human desire for the animals ’beautiful mother-of-pearl shell has led to overfishing in some parts of their tropical Pacific home. “It’s the nautilus’ bad luck that has this beautiful symmetry, ”Ward says. Their shells can cost $ 1,000 on eBay. Between 2005 and 2014, trade data collected by the U.S. Fish and Wildlife Service indicated that more than 100,000 whole nautilus shells and 800,000 parts were imported into the United States alone. Some previously abundant populations in the Philippines, where nautilus are also hunted from time to time for food, have already become extinct.
As climate change approaches, there is also a single question among all that remains about nautilus: can they survive us?
Undoubtedly, nautilus has always been a survivor. Ancient and cunning, their lineage was adaptable enough to persist in the five major extinction events of Earth’s past. Their ancestors, the nautiloids, appeared half a billion years ago. They were the first cephalopods, a group of mollusks that today includes octopuses, cuttlefish and squid.
At the time, most life crawled on the seabed, but nautiloids were able to float suspended in the water, a key innovation they achieved by removing liquid from their innermost chambers to match the density of the sea. seawater surrounding them, making them essentially weightless. The first nautiloids had straight, conical shells, but soon evolved the coiled spiral with the interconnected inner chambers seen today in the nautilus. In their current incarnation, they have sailed the oceans for at least 100 million years.
It was in this form that they capped the asteroid that ended the dinosaur era. The remnants of the impact and the ashes of the fires that then erupted darkened the sun for two years, killing most of the photosynthesized plankton that formed the basis of the trophic network in the shallow waters. The nautilus species that lived near the surface probably became extinct along with their relatives, the ammonites.
The same but different: a nautilus with a floating chamber next to a diffuse nautilus, with its viscous outer layer. Photo of Peter Ward
But in the perpetual twilight known as the Mesopelagic Zone, between 200 and 1,000 meters below the surface, other species of nautilus persisted. And because today’s yachts are believed to be mostly scavengers, death and mass destruction may even have benefited them, Ward suggests. After all, he says, “What was left after the end of the Cretaceous? Dead bodies.”
A more personal tragedy kept Ward from nautilus field research for several decades. On an expedition to New Caledonia in late 1984, his diving friend drowned while the couple watched the nautical traps. The 2015 expedition was his first foray into Papua New Guinea.
The team, which included TNC’s Barord and Richard Hamilton, traveled to Ndrova aboard a 14-meter stabilizing canoe and two poles that Matawai had built for a climate change awareness trip a few years earlier. The island is a particularly good place for nautical research: the seabed moves so abruptly away from its shores that a trap placed at the bottom hundreds of meters below the surface can simply be tied to a coconut tree. .
The head of Ndrova, Peter Kanawi, welcomed the investigators and 18 members of the community joined the expedition as assistants. Every evening, as the tropical sun sank into the sea, the team went out in small motor boats and lowered the traps: cubic metal frames covered with chicken wire and baits with tuna. At dawn, they lifted the ropes by hand, a grueling workout that took nearly an hour to trap, stopping when the cage was a snorkeling distance from the surface.
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Researchers studying nautical in Papua New Guinea catch shell animals to weigh, measure, have sex and take samples before returning them to the water. Video by Dave Abbott
The first night, the traps caught nothing. Some locals speculated that the aliens had not been properly introduced to the ancestors. But a large fisherman who had been on the previous expedition recalled that the traps had been placed in a different place in 1984, at a slightly lower depth. On his next outing, the team did what he suggested. In the morning, Hamilton threw himself overboard to check the trap.
A coral reef biologist accustomed to studying shallow waters, awaited this daily revelation. “You feel like a little kid taking a lucky bath. It was all things I hadn’t seen before: a kind of visual appreciation of how much you don’t know.” Sometimes there were strange eels, and Hamilton especially liked “weird-looking crabs.” But that day, he was delighted to have three diffuse nautilus and three chamber nautilus.
Nautical people are accustomed to the depths and cannot survive long in the warm surface waters of tropical seas. So, once back on board the rocker, the scientists placed the animals in a refrigerator full of seawater, refrigerated with bottles of frozen water.
It was obvious what the fuzzy nautilus were. Their shells were covered with a hairy periostrack or outer layer, which is completely absent in other types of nautilus. “It looks a bit …