This Shark Can Outlast Nuclear Waste. But Will It?
The Greenland shark is surely one of nature’s great mysteries. A slow-moving creature growing up to 5.5 meters long, it is the largest fish in the Arctic. When wrenched from the icy waters, it is like a slab of granite: cigar-shaped, but with strangely flabby skin. It is often afflicted by an unsightly parasite that dangles from its eyes, gradually consuming its cornea and turning the shark progressively blind. Very little is known about how it breeds and eats, but seal, reindeer, and even polar bear body parts have been found in its stomach.
The cold depths of the planet’s north are what the Greenland shark calls home. It is mostly found in the waters around eastern Canada and the USA, Iceland, Greenland, and Norway, and seems to prefer depths of between 150–800 meters (although it can go much deeper), where it is sometimes caught by longline fishing. Unlike some other deep-water species, whose swim bladders distend with changes in water pressure, the Greenland shark’s body shape is undistorted by its long journey to the surface. It remains preserved as it was, far below, and emerges in its full, strange glory.
Throughout recent history, the cold Arctic has lent itself to many a warm-blooded tale: the intensive hunting of whales, seals, and foxes for their blubber and fur, and epics of human survival in this frozen, unforgiving environment.
But there is little mythology to be found about one cold-blooded resident; the story of the Greenland shark has gone relatively untold. Similarly, for such a large animal, it has curiously escaped widespread intensive hunting, at least in recent decades. From the early 20th century to the 1960s, it was targeted for its oil-rich liver—until it was out-competed by less costly alternatives like whale oil and, later, crude oil. Nowadays, it is generally caught only as bycatch, and even then deemed fit only for dog meat. On both the Russian and the Alaskan sides of the Bering Strait, Indigenous Beringians avoid it or are indifferent to it. Apart from in Iceland, where it is turned into a delicacy called hákarl, the shark’s meat is considered bad because it contains toxins that make it largely inedible without processing. If eaten untreated by humans, it produces an effect that is something like extreme drunkenness, as explained in Norwegian author Morten Strøksnes’s delightful book Shark Drunk (2015). The toxicity of the shark’s very flesh—and received wisdom among some Inuit that it takes a disconcertingly long time to die—have led to it being given a wide berth. There is something unsettling about its flesh that twitches long after death.
All this means that Greenland sharks are mostly ignored and left to their own devices, and as such some researchers and fishers speculate that their populations are large and widespread. But most famously, and most mysteriously, this shark can live for a very, very long time.
A Nuclear Underworld
Between 400 and 800 meters below the surface of the earth, an underworld resident of an altogether different kind simmers away unseen. Shrouded in something close to secrecy, concrete barrels of radioactive waste sit nestled in their own heat, quietly and very slowly cooling. The storage facilities that house this waste—a by-product of nuclear energy that provides significant amounts of power to Asia, Europe, and the Americas—tend to be built far from anxious minds. They are not easily found or entered. Some waste is even dumped into the sea.
These barrels are heading into a future nothing alive today will live to see: high-level radioactive material can have a half-life (the time taken for radioactivity levels to halve) of 100,000 years, and the only thing deemed stable enough to contain it are the rocks of the earth themselves. These deep geological repositories are supposed to withstand damage from any type of disaster: earthquakes, floods, wildfires, plane crashes, bombs. Yet complete protection from radioactivity is impossible; it is native to the planet. Radium-rich rock lies under many major cities, and bananas and Brazil nuts contain lots of potassium, of which a tiny amount is radioactive. What’s more, it’s also found in humans: K-40, a type of potassium, is the most common radioisotope in the human body, and it has a half-life of more than a billion years.
Inside every organism are trace amounts of the radioactive isotope carbon-14. Living things absorb carbon compounds, reflecting what is in the atmosphere around them. Embedded within crystallins, a type of protein, carbon-14 is found inside the lenses of animal eyes and constitutes a time capsule from around the moment of birth, indicating levels of radioactivity in the air or ocean. Carbon-14, of course, is also released in vast quantities by nuclear weapons. The amount of carbon-14 in the atmosphere fluctuates, but when a flurry of nuclear tests took place across the globe in the 1950s and early 1960s, there was a particularly huge spike where levels doubled. This would come to be known as “the bomb pulse,” and it was quietly being sealed into the eyes of a generation of newborn creatures—even those deep underwater. It wouldn’t be unlocked until decades later.
Caught in the Undertow
The wind was especially brutal that day in the fjords of 1930s Greenland. It didn’t blow hard in one direction but rather created small eddies, snowflakes chasing themselves in circles in a whirlwind of cold. Accompanied by high-pitched wails, chutes of air barrelled furiously across the ice sheet against an unknown foe. Shades of white were the only color for miles around.
But nothing of this was felt down below in the midnight zone. Under the comforting mass of a kilometer of ocean, sealed in by a thick tranche of ice, these waters move to a different rhythm than the winds. Appearing in the murk, a Greenland shark was making her own slow path on the currents that flowed past her stone body.
She could still remember swallowing the chunk of flesh floating in front of her, then the sickening sensation of being dragged upwards at a speed frightening to her, followed by an otherworldly brightness that caused even her almost-blind eyes to smart. She was startled by the sudden awareness, for the first time, of her own mighty weight; her gills and soft mouth threatened to tear as they strained against the sharp objects hooked in them. She was drowning.
She tried to get free with huge, heavy movements of her body as she was pinned down. A stretch of fear, pain, and then it was all over: the pressure unbuckled, and she felt herself begin to sink again. Something was now stuck to her back, though through her thick skin she didn’t feel it: a tag that followed her as she drifted into the underworld again.
Lucky Carbon Catch
It may not have lasted long, but something remarkable had just taken place on that turbulent day. This Greenland shark had just been caught, measured, and tagged for the first time by scientist Paul Marinus Hansen—and, astonishingly, it would not be the last. Sixteen years later, the very same shark was recaptured by a friend of Hansen’s. This remarkable feat of luck would begin the process of unraveling the mystery of the shark.
That time acts slowly on this species had long been suspected by native Greenlanders, and what Hansen’s friend noticed when he measured her for the second time was that her body had grown a mere eight centimeters in the intervening years. If that was the case, it was evident that this animal must take decades to reach its full size—making it one of the longest-lived creatures on the planet. The difficulty lay in proving it, since the Greenland shark’s entire body—even its vertebrae—is made of soft tissue, making impossible the usual method of counting growth rings in fin spines to determine lifespan.
That is where carbon-14 comes in. Carbon dating has been used since the mid-20th century, but it would take a specialized technique to decode the Greenland shark. Over a decade ago, Danish physicist Jan Heinemeier and four colleagues pioneered a method—initially for use on deceased humans—that used the carbon-14 found in eye lenses to accurately estimate a window of birth. Because carbon-14 has a constant and easily measured rate of decay, it is ideal for such a task (although this becomes more difficult in marine environments, so estimations are less precise).
The technique would eventually reach marine biology researchers John Fleng Steffensen and Julius Nielsen in Greenland, and led to a breakthrough discovery published in 2016. By analyzing the carbon-14 in the lenses of 28 Greenland sharks, and using the bomb pulse as a timestamp, Nielsen and his collaborators estimated that these animals can live to be at least 272 years old, and the oldest alive today could be more than 500. It is believed to reach sexual maturity around the age of 150. Almost 100 years after Hansen first tried to study it, the puzzle was solved. Centuries of growth; centuries of longevity.
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It is common to read that the #greenlandshark is blind due to a parasitic infection on the cornea. I am however not convinced about this at all… that being said, the relatively small eyes are probably not that important in a low-light environment at 300-700 m of depth which Greenland sharks typically inhabit in the part of the #Arctic where my PhD research was carried out. This piece of footage was taken exactly 3 yr ago on board research vessel Sanna during a capture-tag-release expedition in south #greenland 🦈 #greenlandsharkproject #sharkscience #marinescience #shark #oldandcold #tagandrelease #extremefishing #deepseafishing
On that day, after shaking off the shock, the Greenland shark swam off into the blue at a pace of less than 1.6 kilometers per hour. Like many creatures that live a long time, her species moves extremely slowly. On a particularly energetic day, she might reach 2.7 kilometers per hour.
She might have meandered off to find her next meal, more wary this time of suspicious pieces of flesh suspended in the water. Perhaps she would have eventually cruised along the muddy bottom of the Kara Sea, weaving between rusted barrels: multiple tons of radioactive waste dumped by the Soviet military that still sit deep beneath the waves. Not all nuclear by-products end up underground.
Greenland sharks are presumed to be scavengers, eating whatever they happen to find, because their lethargic pace could not allow for any other possibility. Although there is some evidence (mostly in the form of strange bite marks) that they can hunt live seals, it remains unwitnessed and unknown how they really feed. Yet even living at the great depths that it does, something more disconcerting has been found in the stomachs of these sharks: plastic. Plastics that live well beyond their intended use—and that can outlive even the Greenland shark.
Sharks have been on the planet in some form for around 450 million years, predating mammals, insects, dinosaurs—and, of course, humans. They have survived all five of Earth’s “mass extinctions.” The long life of an individual Greenland shark is nested in the remarkable ecological durability of the species at large. When a Greenland shark is born, it is setting out on a momentous task—that of merely living—in a life that takes such a long time to gather meaning. Like the geological repositories of deep underground, they are built to outlast most of what the elements can throw at them. But maybe not everything humans can.
The failure to tackle or even to comprehend the existing ecological crisis is said to be, in part, an issue of scale. The planet accommodates species, like sharks, that have barely evolved for millennia, and at the same time is threatened with irreversible, catastrophic damage within ten human years. Disrupted worldwide weather systems and a planetary history of several billion years must be thought of alongside the startling immediacy of human waste filling the oceans, insurmountable piles of disposable plastics that are useful for perhaps ten minutes on average. How can that be?
Nuclear waste, in its aching, lingering presence underground, confronts us with a newly ungraspable sense of time. Yet it is somebody’s job to consider how to communicate a message into the future, so that whoever receives it may understand the danger of those barrels beneath the earth.
The reach of deep time, both forwards and backwards, is on a scale no one can truly imagine. But if the distance between “human time” and “geological time” is collapsing, as human beings have become capable of inflicting great changes upon the planetary body, then we must assume that there is a record of it somehow. Where does this leave the Greenland shark?
Forgotten Past, Forgotten Future
The slow-moving Greenland shark swims through time on multiple scales at once. Its species history is as long as any that can be measured; its individual time on the Earth is longer than that of any other vertebrate. These animals can be seen to embody a kind of hybrid time, existing at the crossroads of human activity, geology, and the ongoing story of their own species.
As “living fossils,” Greenland sharks not only represent the longevity of their species throughout time, but the arc of geo-human history: nuclear history is stored in their eyes, and human-made plastics will accompany them on their long journey into the future. These are creatures of immense power and significance: steady bearers of a forgotten past that will carry the marks of present into the future. An organism living at the extremes, fantastical and alien and real.
Our Greenland shark of the 1930s could still be alive. Out there, right now, others like her will continue to coast beneath the waves. If she is captured again in the future, what will researchers find in her eyes, in her stomach? We need, in Richard Crownshaw’s words, a deeper sense of history that both precedes and supersedes humanity’s chronicling of itself. The Greenland shark, mysterious and hidden from view, is testament to the ability to adapt to planetary turbulence when the future seems uncertain.
Toxic and unwanted, if all goes to plan, nuclear waste will rest in peace for centuries to come. Concealed beneath the waves, the toxic flesh of Greenland sharks will also remain that way. They do not belong on land, and they are not much desired; they are creatures of the deep. Both radioactive material and the Greenland shark arouse an eerie fascination, encountered as by-product, as bycatch. As things out of time and out of place, they can be seen to disrupt a linear understanding of history. By looking to sharks’ 450-million-year legacy, and their strange, startling crossover with radioactive waste’s own long trajectory towards the unknown, time and resilience come to take on different meanings entirely.
The Greenland shark can endure longer on this planet than any human. It is a beast whose body will live to tell the tale of the Anthropocene.
Author’s note: I am grateful to Julius Nielsen, whose research informs this article and who generously responded to my questions.
Featured image: A Greenland shark. Photo from Wikimedia Commons.
Sadie E. Hale is a research master student in Environmental Humanities at Vrije Universiteit Amsterdam. Her research interests span nonhuman animals, meat consumption, and masculinities. Her scholarly writing has appeared in the European Journal of Women’s Studies. She previously studied Gender at the London School of Economics and Literature at King’s College London. Twitter. Contact.