MThe first sight of it came one morning in June, as I rode the ferry through the Bosporus strait: a toxic glint on the sea’s surface. Initial thought was that it was oil from one of the large container ships that pass through Istanbul via Bosporus. The glint became more apparent as a sallow sludge began to settle around the boat. It was thicker than fiberglass insulation in some places. Its surface was covered with foamy bubbles, viscous puddles and was littered by balloons, bread crusts and Styrofoam food containers.
It’s called marine mucilage, but the world knows it better as “sea snot,” thanks to the tsunami of stories that went viral when it overtook the Sea of Marmara in May. While the internet was astonished at the mess, it moved on to other things. But here in Istanbul, the sea-snot took over the summer. Its unavoidable presence dominated conversations and closed down beaches. It was more disturbing for some people.
This isn’t what I imagined global warming would look like. I was braced for bigger wildfires and rising seas; I wasn’t ready for sea snot. If the story of the Sea of Marmara in the summer of 2021 is a preview of what’s to come, the effects of climate change will be not only terrifyingly destructive but also weird, uncomfortable, and unbearably gross.
THe Marmara This historic inland sea connects the Black Sea to the Aegean via Dardanelles straits and the Bosporus. The shores of the island are lined with factories and ports. There are also piers, summer homes, summer houses, and factories. Here, fishermen still catch anchovies, sea bass and mullet. However, over the past ten years, marine species like bluefin tuna or swordfish have become commercially extinct. Additionally, the populations of many other fish species have declined. Jellyfish have also populated the coastline, all signs that the ecosystem is in trouble. The mean surface temperature of the Marmara, like that of many seas, is rising due to climate change, but the Marmara’s has increased by 2.5 degrees Celsius—1.5 degrees more than the global average, making it a leading indicator for seas around the world.
The Marmara was hit with severe warming due to decades of overfishing and pollution. At the end of 2020, increased concentrations of phosphorus and nitrogen led to a boom in phytoplankton, single-celled organisms whose name means “plant drifter” in Greek. The Marmara’s warming surface temperature also caused its waters to stratify, slowing the currents that would normally help disrupt algae growth.
The phytoplankton ran out of nutrients eventually, and some species began to emit a sticky substance. As the cells died, they collided with each other and became stuck together, creating globs in the warmest layer stratified water. With time and exposure, the globs turned into a submerged mat of mucus that trapped nearly everything around it—bacteria, fish larvae, dead cells, debris. Bacteria thrived on the dead phytoplankton, adding to the mat’s mass. “At that point, it takes on a life of its own,” Mustafa Yucel, a marine-science professor at Middle East Technical University’s Institute of Marine Science, told me. With increasing water temperatures, he said, we should prepare to see more extreme reactions in our seas—including invasive-species outbreaks and massive algal and seaweed blooms.
The fisherman Roy Oksen, the chief of one of Istanbul’s fishing cooperatives, remembers the first time he couldn’t pull his fishing net into his boat. It was getting weighed down by something. He asked a friend to help him and they lifted the net from the water. Instead of fish, the net was full of a dark, slippery liquid. Soon, he explained to me that the mucilage was clogging nets as well as boat motors.
I met Oksen at his fishing co-op’s headquarters, a harborside hut where we sipped tea surrounded by coiled ropes and the smell of bait and petrol. The window, which was usually a view of water, was covered with flyers that stated that seafood from Marmara was safe to consume despite the mucilage. Oksen explained that a fish which would have cost 50 lire before the outbreak of sea-snot would now fetch 10 lire, even though he was trying harder to catch more fish. Even worse, the news of the outbreak had caused a 70% drop in fish sales around the Marmara. Oksen and other fishermen had to stop their season because of equipment problems. “If this continues this year or next year, I’ll have to go look for a new kind of job to survive,” he said.
AThe mucilageAs it fell below the surface, it began to rot and undergo a horrible metamorphosis. The bacteria and viruses that caused the decay were responsible for the release of more mucus, gas, and bursting of the phytoplankton cells. The mucilage started to rise as the gas inflated it. It broke the Marmara’s surface in May and made its grand entrance to the public eye. It pooled in the shallow bays near Gebze, haunted the harbors around Erdek, and flourished on the shores of Istanbul’s tony Princes’ Islands. Kadıköy smelled like rotten eggs. The sea-snot epidemic was covered in the media, and the world reacted with disgust.
In early June, I went to Kadıköy, a trendy neighborhood on the Asian side of Istanbul that had been hit hard by the outbreak. Some of the mucilage mats were as thick and dense as a ’70s shag rug; others were light and frothy, like a frappuccino. On a normal summer day at the Kalamiş Marina, one of Turkey’s poshest, yachts glide in and out of their slips, whisking people to the Princes’ Islands or on a sunset cruise. To stop the mucilage from getting into the marina’s waters, staff put an orange oil-spill boom into the water. But it quickly overcame the boom, and soon the marina’s waters were carpeted with mucilage. The sea snot was used to seal the yachts. The sailors were threatened by flies that gathered around the mucilage. People no longer wanted to be near the water, Nail Baktır, who runs a sailing school in the marina, told me. He stood on the deck of his boat docked and pointed to the scum covering its hull. When he first noticed the mucilage, it was thought that the masses were microorganisms living in the sea. “We’re done. The Marmara sea is over. The bodies are floating.” His blunt conclusion: “We killed the Marmara.”
As Baktır alternated between gripping the boat’s wheel and stroking his long captain’s beard, he said that although he had spent his whole life in Istanbul, the mucilage was making him consider a move to southern Turkey, where the water is cleaner. Maybe, he said, his grandchildren will see the Marmara the way it was when he was a child—if environmental concerns are taken more seriously in the future.
Meanwhile, the bacteria in the mucilage degraded, releasing enough gas to inflate small surface bubbles, ballooning the mucilage into conglomerates that scientists call “clouds.” With the clouds acting as sails, Turkey’s fierce westerly lodos The Marmara was covered in mucilage. Some flocs—as loosely clumped masses of mucilage are called—sailed all the way to Greece, raising concerns about the international spread of bacteria and viruses (none of my sources was aware of any reports of illness directly attributed to the mucilage).
I passed a team municipal workers in life vests, wearing Aegean-blue shirts. They were scooping out the sea snot with what looked like pool skimmers, as I left the marina. They scooped the mucilage into bags and tied them to a truck for incineration.
Elsewhere on the Kadıköy seafront, more oil-spill booms temporarily corralled the mucilage so that it could be siphoned up by trucks with high-suction vacuums. The water was filtered by municipal cleaning boats, which collected solidified mucilage using conveyor belts that were used to remove litter. The efforts seemed sincere, but Sisyphean. The phenomenon is unprecedented and there is no infrastructure to deal with it.
FOr for more than a century, the Princes’ Islands have served Istanbul’s bourgeois as a refuge from the pollution and other unpleasantries of the megalopolis. People travel the archipelago’s car-free islands by foot or in a carriage, passing neoclassical vacation home that could have been home to Leon Trotsky. Yet on a cloudless, 80-degree day in July, the islands’ beaches sat empty. One cove had a row of colorfully arranged lounge chairs, but no one was able to sit in them. The sand was not marked by footprints. Just offshore, mucilage swirled like the contents of a witch’s cauldron. According to Ayşen Erdinçler, an environmental-science professor at Boğaziçi University and the head of Istanbul’s Department of Environmental Protection and Development, the risk of contracting a bacteria-borne illness from swimming increases 12 to 18 times when concentrated mucilage is present.
As in Kadıköy, municipal vessels chugged through the snot, endeavoring to suck it up with industrial hoses. The scene was viewed with astonishment by pedestrians, who paused to look at the scene with furrowed brows. Tourists ran past with cameras and masks around their necks, carrying their cameras. One woman tsk-ed; another covered her nose and mouth, disgusted at the sight or smell of it all. This time it wasn’t the mucilage itself that struck me—desensitization had kicked in—but the surreality of a summer without swimming. Our summer had become a René Magritte painting, a collision of ordinary objects producing an unfamiliar whole. “Everything we see hides another thing,” Magritte once said, and as I watched the mucus curdle in the water, I wondered what else it veiled.
Some people stood at the water’s edge in their swim trunks, either debating their options or persisting in denial. Some beach-club owners, desperate to put patrons at ease, baptized themselves in the now-umber water, reemerging with proclamations such as “See, nothing happened to me! I’m fine!” Whether or not this demonstration reassured people of the water’s safety, they wearied of the heat, and soon they were creeping back to the shoreline.
One hot and humid Saturday, as I contemplated my first swim since the outbreak began, I sat on the dock at the islands’ edge, contemplating my first. It was Turkey’s second-hottest July on record since 1971, and the prospect of swimming in the sea was seductive. Besides, the mucilage was no longer floating in chunky continents, as it had in June; it had become lighter and creamier, the shade of a café au lait. I had swum in murky waters before, I told myself—in stagnant Sierra lakes at summer camp, and in the bogs of the Mekong River. I watched as some of my friends lowered themselves into the water, cooling their bodies and straining their necks to keep above the water. My stomach began to churn and my body froze as a small blob of mucilage surrounded my feet. The pleasures of the ocean were still not within reach.
Longing to reunite with the water, I remembered a scene in Orhan Pamuk’s novel The Museum of InnocenceA scene in which a character backstrokes on the Marmara in order to cure his loveickness. What’s lost when we lose touch with our environment—when a place we turn to for solace or enjoyment is suddenly inaccessible? I knew that the Nobel Prize–winning author, like his character, is an avid swimmer, so I called him to ask how he had been affected by the outbreak.
“When I swim, I am a better thinker, that’s for sure, and also my psychology changes—it gives me some kind of self-confidence,” he told me. “Swimming takes me from a relatively depressive mood to a relatively creative mood.” He went on to observe that this summer, swimming was the new smoking—people avoided the mucilage as if it were carcinogenic. “People are so psychologically scared of this ugly mucilage,” he said. He imagined them on their balconies, watching him swim: “It is the serious novelist Orhan Pamuk!”
LLike many environmental disastersThe sudden onset of mucilage was a result of several long-term trends. To better understand them, I took a train from Istanbul two hours east to the Gulf of İzmit. Behind a manicured waterfront of willow trees and park benches, a defunct paper factory testifies to the area’s industrial roots: A century ago, some of Turkey’s first factories produced military uniforms and fezzes here. The gulf continues to be the industrial heart of Turkey. Ford and Goodyear both have factories in this area, as well many chemical and fertilizer companies. The five ports and 35 industrial Docks are all available for use.
Hakan Osanmaz, an environmental-inspection seaplane pilot based in the gulf, had promised to give me a new perspective on the Marmara. We sat in a stuffy prefab office by a dock, lined with photos from Osanmaz’s years jetting tourists around the Mediterranean coast. He wore a tie-dyed Nirvana T-shirt, and he ruminated on the changes he’d seen in the Marmara during his 15 years of bird’s-eye views. The water was once so blue that “it used to look like the Maldives here,” he told me. “It’s kind of like the sea is throwing up. It’s a catastrophe.”
Usually, Osanmaz’s job is to document illegal waste dumping for the local municipality, but since the outbreak, it’s also meant organizing a WhatsApp group to orchestrate the municipality’s mucilage-cleanup efforts.
The outbreak can be seen from the sky. From Osanmaz’s plane, I could see how monstrous Istanbul had grown. Over the past 50 year, the city has spread along the Marmara coast, filling its coastline with high-rise condos, tract homes, five-star hotel suites, and office complexes. Twenty-five million people, along with half of Turkey’s industry, inhabit the area around the Marmara, and their waste adds to the sea’s burden. Numerous rivers and streams also carry waste into the Marmara. Some of the pollution comes as far as Western Europe via Danube, which empties into Black Sea and flows into Marmara. Osanmaz regularly documents illegal dumping by international ships passing through the ocean.
It turns out that the way wastewater is treated plays an important role in preventing mucilage from forming. “Among the sources of marine pollution, 53% of the water coming to the Marmara Basin is discharged into the sea with only pre-treatment, that is to say by discharging the waste water in the houses only by passing it through sand filters and precipitation,” Ayşen Erdinçler, the environmental-science professor, later told me in an email. Advanced water-treatment plants, she stated, would remove more of phosphorus, nitrogen and make mucilage outbreaks less likely. They would also allow water to reoxygenate. The Marmara Sea Action plan, which was established by the Turkish government to address the outbreak, has seen existing wastewater-treatment plants being upgraded. New ones are expected to be constructed within three years.
One day in JulyThe mucilage disappeared suddenly. Istanbul woke up to a sparkling ocean. People flooded the shoreline convinced that the nightmare was over. Alice Alldredge, an emeritus professor of marine-biology at UC Santa Barbara, was my first call to find out what could have been. “It most likely sank,” she told me. Scientists aren’t sure exactly why, but every once in a while, mucilage mats will just drop back below the water’s surface.
To follow the fate of the mucilage, I reached out to Serço Ekşiyan, who has been diving in the Sea of Marmara for half a century. We sat together in his wooden boat that he had purchased used and restored as it floated in its slip at a derelict fishing harbour. His dives always had a purpose. As a teenager, he spearfish to sell fish to restaurants. Later, he spent many years clearing abandoned nets out of the sea and transplanting coral to a marine reserve he helped to establish.
I asked him if the muclage had actually sunk. “It’s true,” he said. The mucilage is thicker when it is floating near the surface than it is below, but it shrinks as it sinks to a thinner, denser layer less then 10 meters thick. Ekşiyan’s dives are now spent documenting the mucilage with a homemade GoPro fashioned from a security camera and a plastic case. He showed me a compressor he uses to fill the oxygen mask that he made from Cold War–era U.S. Air Force plane components that had been sold to the Turkish military.
Diving in the mucilage, Ekşiyan said, is like drifting through a nightmare; the mucilage hangs in massive webs, and even at noon the visibility is so low that it can feel like diving at night. As the mucilage sinks and continues to compress, it covers the seabed. It blocks the entrances of caves and underground caverns, which evicts fish from their homes. As the mucilage continues to decompose, it consumes oxygen, creating a dead zone—an area without enough oxygen to sustain life. The coral Ekşiyan had transplanted bleached due to the mucilage and abandoned nets, but it managed to survive—for this year. “And the reefs,” he said, “are like abandoned villages.”
Asutay Akbayır, the regional manager of the Professional Association of Diving Instructors diver-training organization, comes from a family of divers; like Ekşiyan, he has been diving in the Marmara for decades. He told me that even before the mucilage epidemic, diving guides and instructors were losing their jobs due to the Marmara’s pollution. “Most of the divers, they don’t prefer to dive in challenging environments where the visibility is very low,” he said. “You are not even able to see your own hand when you dive, your own body.” But Akbayır hopes that recreational diving will evolve, not disappear. Perhaps divers will be ambassadors for sea life, telling the public all about the underwater destruction.
What I’d been looking at all summer, I realized, was not only an unfamiliar phenomenon but also an unfamiliar kind of death. To confront global warming is to confront death, and it will show up in surprising places and forms—some painful, some disgusting, some disorienting. We talk about preparing for climate change, but how can we prepare for endings we can’t yet imagine?
By summer’s end, life above the surface felt normal. The beaches were crowded and the water was clear. People ordered fish from restaurants with abandon. It was as if there had never been a sea-snot outbreak. It had been a global story in May; by July, it was only the Turkish media that were paying attention. By September, it had become a non-recurring topic of conversation.
It was a summer marked by extremes in many bodies water around the globe. Florida was hit with red tides. There were also algal blooms and bacterial outbreaks in numerous lakes, reservoirs, and ponds in Massachusetts. Lake Superior was hit with toxic blue-green algae. The United States had reported 476 toxic-algae cases in October, the second-highest total ever recorded. Glacier scientists are investigating the appearance of pink ice at Italy’s Presena Glacier, an Alpine region known for skiing and outdoor sports. Research suggests that the algae could play a role in increasing glacial melt.
A recent study published by a team at the Swedish Museum of Natural History, in Stockholm, and the University of Nebraska at Lincoln argued that these extreme blooms, and the dead zones left in their wake, parallel the beginnings of the worst extinction event in Earth’s history—the Permian-Triassic extinction, which happened some 252 million years ago and is sometimes called the “Great Dying.”
In September, just as the Turkish summer was shifting into fall, I got a phone call from Mustafa Yucel, the marine-science professor, who was inviting me to meet him and his team when their research vessel docked at Istanbul’s Port of Haydarpaşa. They had spent a week at sea checking their observation stations, and they reported that most of the mucilage was gone—likely consumed by bacteria and fish.
“But the conditions that led to this mucilage bloom are still present,” Yucel cautioned. A marine system is more vulnerable to extreme reactions than it is to pressure, such as a mass die-off or an explosion of chunky, smelly mucilage. Or both. “The Marmara is now an extreme ecosystem—extreme in algae, bacteria, and lack of oxygen. That’s why it’s hard for us to predict what’s next,” Yucel said. “The sea snot may come back, because the conditions are there, but it could just as easily be some other extreme—hydrogen sulfide, a red tide, massive fish kills rotting on a beach … Disgusting events will increase in frequency and magnitude.” And as they do, they will also become more and more unmanageable.
“Whether we directly attribute it to climate change or to pollution, mucilage is a symptom of the unsustainable use of our planet,” says Antonio Pusceddu, a marine biologist at Italy’s University of Cagliari and one of the world’s handful of mucilage experts. “The rate at which our planet changes now is unprecedented.” Though Turkey’s mucilage outbreak is the worst on record, smaller outbreaks have occurred along the coast of Australia and in the Mediterranean. When one particularly large and disruptive outbreak hit Italy’s Adriatic and Tyrrhenian coastlines in 2009, Pusceddu and his colleagues investigated the relationship between climate change and the frequency of mucilage outbreaks in the Mediterranean Sea over the past two centuries. They found that the number and severity of mucilage outbreaks had increased nearly exponentially in the 20 years prior. He explained that in the past decade, better wastewater treatment has reduced or eliminated the severity and occurrence of mucilage it Italy.
In response to the sea-snot saga, the Turkish government designated the Marmara Sea as a special environmental-protection zone. This status requires a stricter review process for commercial maritime activities, more factory inspections, and fines. It also means that the Marmara Sea will see an increase in the amount of water that is treated with advanced biological treatment, from 46 to 100 per cent within three years. However, it is unclear how these measures are funded and enforced.
After talking with Yucel and his colleagues in the Port of Haydarpaşa, I stepped off their research vessel and looked back at the Marmara. I wanted to feel as much relief as the rest Istanbulans. To be able to float in the sea’s tides and gaze up at the blue skies, I could jump back in the water. I wanted to believe the water was clean and that the source of the disgusting ooze had been removed. As I looked at the water, something else happened. I felt a new sense of disgust. Only this time, it wasn’t a reaction to the mucilage. Marine ecosystems will become less predictable and delicate as humans continue to heat and pollute the sea. Each outbreak shows us the consequences of our own actions—if we choose to see them.
This AtlanticPlanet story was supported and funded by the HHMI Department of Science Education.