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A thick blanket of ‘sea snot’ is wreaking havoc on Turkey’s coast

A drone photo shows an aerial view of the mucus covering a harbor near Istanbul earlier this month. (Anadolu Agency/Anadolu Agency via Getty Images)
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For months, Turkish fishermen in the Sea of Marmara have been running into a problem: They can’t catch fish.

That’s because a thick, viscous substance known colloquially as “sea snot” is floating on the water’s surface, clogging up their nets and raising doubts about whether fish found in the inland sea would actually be safe to eat.

Scientists say that the unpleasant-looking mucus is not a new phenomenon, but rising water temperatures caused by global warming may be making it worse. Pollution — including agricultural and raw sewage runoff — is also to blame.

As the Guardian and numerous Turkish news outlets have reported, high levels of nitrogen and phosphorus in the Sea of Marmara, situated between the Black and Aegean Seas, are leading to an explosion of the phytoplankton populations that discharge “sea snot.” Though the mucus itself is not necessarily harmful, it can become a host to toxic microorganisms and dangerous bacteria such as E. coli. And when it forms a layer that covers the water’s surface, it can set off a harmful chain of events, preventing fish from being able to breathe, causing mass die-offs, which in turn leads to plummeting oxygen levels that choke other forms of marine life.

In April, marine biologists discovered that the mucus could be found blanketing corals on the sea floor nearly 100 feet below the water’s surface, potentially smothering them, Turkish newspaper Cumhuriyet reported. Thousands of fish have since been found dead in some coastal towns.

The problem has become harder to ignore in recent weeks as Istanbul’s coastline begins to resemble a beige carpet, but fishermen who rely on the sea to make a living have been sounding the alarm for months. One told Cumhuriyet that he has been unable to work since January because the mucus was rendering his nets useless. A diver who hunts sea snails for a living told Turkey’s state-run Anadolu Agency that he had lost most of his income because the visibility was so poor underwater, and that crabs and sea horses were dying because the slimy mucus was clogging their gills.

The Seaweed Invasion

Though first observed in Turkey in 2007, sea snot appears to have periodically plagued the Mediterranean Sea since the 18th century, Özgür Baytut, a lecturer in hydrobiology at Ondokuz Mayıs University, told BirGün. What is “not normal,” he said, is how frequently it now shows up along Turkey’s coast.

Since phytoplankton thrive in warmer waters, scientists suspect that climate change may be a factor. This past winter was milder than usual, meaning that the Sea of Marmara remained several degrees warmer than average. Mustafa Sari, a professor at Bandırma Onyedi Eylül University, told the Kisa Dalga podcast that the massive, sticky clumps of mucus were “a situation where climate change becomes visible."

Experts have also pointed out that untreated waste and agricultural runoff pour directly into the Sea of Marmara, and cracking down on those sources of pollution would help to reduce nitrogen and phosphorus levels. Overfishing could also play a role, since it means that phytoplankton have fewer natural predators.

Officials in Istanbul, which sits on the Sea of Marmara, announced earlier this month that they were collaborating with the Turkish government and Bandırma Onyedi Eylül University to come up with a solution to the crisis, which may involve bringing in boats to dredge the sea floor. In Izmit, workers have laboriously collected more than 110 tons of the mucus, which was sent to an incinerator for disposal.

Concerns that the unappealing mucus could discourage tourism abound, and some have called for the government to do more to prevent the problem from reoccurring. Ismet Cigit, a columnist for the newspaper Ses Kocaeli, lamented that humans had “betrayed this world’s most beautiful sea” by allowing chemical storage facilities, fuel tanks, factories and other industrial sites to be built along the coast.

“Clearly, there are no deterrent penalties for those who pollute the sea,” he wrote in Turkish, adding, “Marmara is dying.”

This report has been updated.

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