When I was a kid, I once took part in something similar. We tied a friend to a post on the foreshore, and after a while everybody disappeared. I remembered I had to go home for dinner. A grown-up, who’d just happened to pass by, heard a boy shouting for help. The water had already reached up to his chest.
The intertidal zone isn’t land and it isn’t sea. It’s something in between. All organisms that have adapted to these conditions have a foot in both worlds. One moment they’re underwater, and the next they’re on land that’s nearly dry, maybe even under a scorching sun. They have to tolerate salt and water and rain, wind and dry spells. They have to protect themselves against everything that wants to eat them, from both the sea and the shore, and defend themselves from the birds overhead. Just like in the sea, here it’s a matter of finding shelter and food, and also of hanging on tight whenever the waves come rolling in, waves that are often strong enough to move huge boulders.
For this reason, everything that lives on the foreshore must have extreme characteristics. Crabs, snails, and bivalves have almost impenetrable shells. Many species burrow into the sand when the tide comes in. The crab species Hyas coarctatus, commonly called the pyntekrabbe or “decorative crab” in Norwegian, covers itself with algae to make itself invisible. That doesn’t sound especially “decorative.” But on its shell are tiny hooks that can attach to kelp and sea grass, or to whatever drifts past, so the crab changes camouflage depending on its surroundings. Sometimes I think of this crab as a vagabond of the sea, at other times as a creature that merely wants to fit in.
Many types of snails live both on land and in the water, just like crabs. The hermit crab has no natural means of protection, so it carries around an empty seashell on its back. If danger arises, it scoots inside. The hermit crab is a squatter, constantly moving, because as it grows bigger, it has to change houses.
The common limpet slowly crawls around in search of food before clinging to rocks so tightly that tools are required to pry it loose. Limpets are edible, but I’ve never been served them anywhere in Norway. Scientists have discovered that the limpet’s teeth, which are more than a hundred times thinner than a human hair, are made of the hardest biological material on earth. The fibers partly consist of a material called goethite, named for the German author Johann Wolfgang von Goethe.
The roe of sea urchins is also edible but present only during the winter, before spawning. At that time, it’s possible to scrape loose the small eggs, which are the most powerful sea elixir. Crushed and empty sea urchins are often found scattered over the rocks. This is because, at low tide, crows and seagulls pick up the sea urchins and drop them onto rocks from a height of about fifty feet to smash them open and make the food inside easily accessible.
The sandhoppers are leaping among the rocks. At the edge of the low tide area, spawn hide in the kelp and seaweed and among the sea anemones. The sandhoppers hide between the tentacles of the dead man’s fingers (Alcyonium digitatum), in the cilia of sea pens (Virgularia mirabilis), or even between the spines of sea urchins. The mouth of a sea urchin can open and close symmetrically, like ice-cube tongs, and is called in biology “Aristotle’s lantern.” It consists of eight identical parts connected in a circle, opening and closing like a little miracle of precision engineering. Hugo has long been planning to make a large-scale sculpture of the mouth of a sea urchin.
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The wet white sand makes me think of something I once read about the early Christians, who were persecuted by the Romans and used secret signs to test whether they could trust one another. Whenever two people met, and either or both suspected they might not belong to the same religious sect, one of them would draw a long arc in the sand. If the other person drew a new arc, reversed and crossing the first one, the drawing would be complete. The finished image was a fish. Most of Jesus’s first disciples were originally fishermen—before they became “fishers of men,” as they called themselves.
The intertidal zone is wondrously wide. The moon and sun are practically lined up, so their gravitational forces are working in tandem. Ninety-seven percent of all the water on earth is found in the ocean, and all the water on earth is pulled in the same direction until stopped by land. The farther north in Norway you go, the greater the difference between high and low tide.
In the old days, coastal people would collect cockles and ocean clams on the foreshore. Ocean clams burrow into the sand but leave behind tiny holes. If you poke a stick into the hole, the clam will close up around it and you can pull it out. During the Lofoten fishing season several generations ago, both ocean clams and cockles were salted and used as bait.
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A big jellyfish has recently washed ashore. The tentacles of a jellyfish trail behind, with thousands of tiny harpoons or barbs. It hunts by sinking down through the water column, with the tentacles spread out to the side so they can reach anything edible and stun it. When the jellyfish is alive, of course. It’s impossible to say what killed this particular jellyfish, and I’m not planning to perform an autopsy. Jellyfish don’t actually have a brain. Still, the whole creature reminds me of one big brain, carelessly ripped out of a human skull, trailing long threads made of nerves, arteries, and veins. Primordial brains floating in brine.
When philosophers want to challenge our perceptions they often ask: How we can be sure we are not a brain in a vat of liquid, being fed impressions of the world? Most often, their answer is: We can’t.
My subconscious is also stretching out its tentacles to transport flotsam from the past up to the surface. One of my earliest memories is of the time I buried my hand deep inside a stinging jellyfish that had washed ashore on a desolate beach in eastern Finnmark. I probably thought it was actually some sort of jelly, or maybe that industrial waste product they packed in colorful boxes and sold to us kids at the time—a sort of sticky green or red slime that felt cold to the touch. I can still vividly recall the pain, which gradually increased, like nettles only much worse. In 1870, a stinging jellyfish that floated into Massachusetts Bay measured more than six feet in diameter and probably weighed more than a ton. In the southern Pacific Ocean there is a box jellyfish that can stop a grown man’s heart in a matter of minutes.
The jellyfish in the Narcomedusae order is also said to be a tough little devil.
As a life-form, jellyfish have survived many mass extinctions. They can tolerate acidic water, they have few predators, and they drift around like zombies. Jellyfish need hardly any oxygen. They have survived crises that have killed almost everything else on the planet.
Over the course of five hundred million years, five catastrophic mass extinctions have occurred on earth. The best known is the last one, called the Cretaceous-Paleogene (K-Pg) mass extinction event. It happened 65.5 million years ago. The reason it’s so well known is that all the dinosaurs died, except for some small flying lizards.
An asteroid many times bigger than Skrova crashed into the Yucatán Peninsula at a speed of approximately forty-four thousand miles per hour. It’s estimated that the explosion had the same force as hundreds of millions of hydrogen bombs. This was probably the worst day on earth since life began. Large parts of the American continent were pulverized, and the rest was left in a suffocating darkness of dust. Tsunamis occurred that were so powerful they changed the shape of the continents. Dust clouds covered the atmosphere so that the sun was not visible for months or years. Most of the forests that covered the earth burned down. Acid rain filled the sea. It was a sulfurous pool for several million years.
This wasn’t even the worst mass extinction. The Permian-Triassic (P-Tr) extinction, which occurred 252.3 million years ago, was much more extensive. It may have been instigated by a huge volcanic eruption in the area that later became Siberia—because this was during the time when the supercontinent Pangaea was being formed.
The heat melted the permafrost. For millions of years, logs had been piling up in swamps and on the forest floor. The volcanic eruption started fires, and the earth becam
e like a gigantic charcoal grill. New greenhouse gases got trapped in the atmosphere, and things snowballed, especially in the ocean, which began to release stored methane gas. The connections are uncertain, but regardless, the result was what scientists call the “Great Dying,” or the “mother of all mass extinctions.” Acidification and temperature increases in the sea led to the massive growth of poison-producing bacteria. About 96 percent of life in the ocean—which means the majority of all extant life—disappeared. The sea also lost its ability to bind carbon, emitting instead huge quantities of greenhouse gases.20 The atmosphere was suffocated by smoke and gases. The sea was poisoned.
For several hundreds of millions of years, before any fish existed, trilobites dominated the ocean. There were many different varieties, and they ranged from a twenty-fifth of an inch to three feet in length. Some swam, others moved along the bottom. Some ate plankton, others larger prey. They looked like something between a crab and a lobster, but without legs or arms, although some were equipped with spears or sharp horns. Since they were so numerous and also protected by a shell, a tremendous number of these animals have been preserved in stone as fossils. In Norway alone, about three hundred fossil types of trilobites have been identified. But toward the end of the P-Tr extinction, this abundant old branch on the tree of life was abruptly cut off. Toward the end of the Great Dying, every single trilobite died, down to the very last robust individual. It took many millions of years for life on earth to get back on its feet.
Precursors to today’s sharks swam around in the ocean 450 million years ago. About a hundred million years later, sharks had become so prevalent that scientists sometimes call this period the “age of sharks.” Many species of sharks have also gone extinct, including the megalodon, a shark that was nearly sixty-five feet in length and weighed close to fifty-five tons. Its jaws were six feet across and filled with sharp teeth, each the size of a whisky bottle. Another interesting but much smaller creature that died out 320 million years ago is the Stethacanthus, also called the “anvil shark.” On its back it had a helmetlike structure where the dorsal fin usually sits. This structure was filled with teeth pointing forward. Scientists can only speculate what these teeth were used for.
Sharks are the most hardy and adaptable of any large animal ever created by evolution. Some smaller species, like lampreys, horseshoe crabs, sponges, and jellyfish have been around for longer, but they seem somehow like anomalies or accidents. On the other hand, several types of very big sharks, like the anvil shark, goblin shark, frilled shark, and possibly even the Greenland shark, have been around for forever and a day. No other species can match this record. They have survived everything that has been thrown at them, including volcanic eruptions, ice ages, meteor impacts, parasites, bacteria, viruses, acidification, and other catastrophes that have led to mass extinctions. By the time the dinosaurs appeared sharks had already existed for eons. And they continued to thrive even as the dinosaurs and countless other species went extinct. There are still about five hundred different shark species swimming around in the world’s oceans, and half of them have only been discovered in the past forty years. Some are rare and endangered. Others are very abundant and widespread.
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Today eminent scientists at some of the world’s foremost universities have been reporting in leading journals such as Science and Nature that we are in the early phase of the sixth mass extinction. The Great Dying took place over hundreds of thousands of years. Today species are disappearing at such a rapid rate that scientists compare it to the mass extinction that wiped out all the dinosaurs over the course of a few centuries. The driving forces behind this extinction of species are the loss of habitat, the introduction of nonnative species, climate change, and acidification of the ocean.21
We know what is causing this sixth mass extinction. We have been here only a few thousand years, but we’ve spread to all corners of the globe. We have been fruitful and multiplied. We have filled the earth and subdued it. We rule over the fish in the sea and the birds in the sky and every living creature that moves on the ground.
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The chemistry of the sea is changing. Even in coastal areas that were previously teeming with life, there are now large anoxic dead zones. In the deep oceans these zones are even bigger. The sea is clearly not only our most important source of oxygen. It also binds enormous amounts of carbon dioxide and methane, the greenhouse gas that is twenty times more harmful.
The temperature and carbon content are rising in the atmosphere. The ocean’s automatic reaction to this increase is to absorb more CO2. In fact, the sea has absorbed half of all the carbon dioxide we have released since the Industrial Revolution began in the early 1800s.
When carbon dioxide is dissolved in water, the water becomes more acidic. The sea is approaching an acidity level that threatens bivalves, shellfish, coral reefs, krill, and plankton, on which the fish live. A more acidic ocean also affects fish eggs and larvae. Many species, such as kelp, succumb to rising temperatures, while others survive by moving north. But no one can escape the acidity. We probably won’t experience this in our lifetime, but if the ocean becomes too acidic, most of the larger marine life-forms will die out. Negative trends can reinforce one another and cause an entire ecosystem to collapse. Life-giving plankton will disappear, while toxic plankton and jellyfish will survive, possibly along with the toughest sharks in the depths of the ocean.
When the balance is disrupted, various processes are set in motion. For example, as the sea becomes more acidic, its oxygen content also diminishes and its ability to bind new climate-impacting gases is reduced. The sea doesn’t just keep absorbing carbon dioxide as the level increases in the atmosphere. Cold water can better hold carbon dioxide than warm water, just as a cold bottle of carbonated soda stays fizzy longer than a warm one. Eventually, as more carbon dioxide accumulates in the air, the ocean’s ability to absorb greater amounts of it will decrease—and global warming will escalate. One of the worst scenarios a climate scientist can envision is when the sea begins to release the methane gas that is stored on the seafloor and in the ice. Then the snowball effect and feedback mechanism could run amok, and the warming could accelerate to a catastrophic degree.22
During all mass extinctions, including those initially caused by comets, the sea has played a key role. The major cycles and processes in the ocean take place so slowly that by the time problems arise, it’s too late to do anything. The sea has a reaction time of about thirty years.
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Acidification of the oceans has been going on since the nineteenth century, and in the best case scenario it will take many thousands of years before the sea returns to the same pH level it had at the start of the Industrial Revolution. Life in the sea as we know it will end. Possibly millions of life-forms will go extinct before we’ve even discovered them.
Plankton stores far more than half of the oxygen we breathe. If the plankton die, the earth is likely to become uninhabitable for humans. We will become, in the end, like the fish with the dulled eyes, gasping for air in the bottom of the boat. Obviously we could have taken better care of the ocean. But that’s actually a rather self-centered statement, considering it’s the sea that takes care of us. Climate changes, which the sea partially creates because of changes within its waters, will definitely have an effect on us. Over the course of several million years, life in the ocean may return and find a new, productive balance. We, on the other hand, can’t press the pause button for a few million years. The relationship between us and the ocean is not like in some romantic love story, in which the mutual dependence is so strong that we can’t live without each other.
Having said that, entire nations already relate to the sea in almost lovesick ways. This is something I discovered a few years ago when I arrived in La Paz, the capital city of Bolivia. In 1883, the Bolivians lost a war with Chile and had to relinquish their entire coastline. The fact that Chile took the ocean away from them has left a deep scar on the national soul.
The Bolivians view it as the greatest injustice, and they still haven’t given up reclaiming their coast via the international courts. While they’re waiting for their coastal area to come back home, Bolivians try to keep up morale. They have a symbolic navy that bobs around in Lake Titicaca, and each year they celebrate Sea Day (Día del Mar) as a national holiday. Children and soldiers parade through the streets of the capital, for only what is lost is owned forever, though maybe not even that.
The sea will do just fine without us. We cannot survive without the sea.
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On my way back from my walk along the shores of Skrova, I stop to have a chat with the ponies in the small glade where they’re grazing. That’s when my cell phone rings. It’s my fiancée, who, by the way, has eyes that change color like the sea. Since my last visit to Skrova, we’ve found out that she’s pregnant. She is seven weeks along, and everything is going well.
Both of us are happy and excited. We have started reading about fetal development, week by week. For a long time now I’ve also been reading books about fish, and the development of life on earth. I can’t help connecting the two and making some observations.
Inside my fiancée a life is growing, surrounded by amniotic fluid. After seven weeks, an embryo bears a striking resemblance to a fish larva, and the similarity isn’t merely superficial. The fetus has bulges or arches along its upper body. These are pharyngeal arches—gill arches in fish—which, over the course of the next weeks, will grow together to form the neck (larynx) and mouth. Right now the fetus has eyes on either side of its head, like a fish. The ears are way down on each side of the neck. What will become the nose and upper lip is now on top of the head. The indentation we all have in our upper lip is a result of this process. If something goes wrong and the merging isn’t completed as it should be, the child may be born with a cleft lip or palate.
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