BANDIRMA, Turkey – The Marmara Sea, fabulous for centuries for its blue waters and sparkling fish, surrounds the shores of Istanbul. Its perfect shape inspired a 19th-century historian to describe the ancient city as “a diamond set between two sapphires.”
But Marmara has been ill for a long time, and this year it suffered a paroxysm that suffocated its waters and suffocated marine life. In April, thousands of fish died, and in May, a natural secretion called mucilage emerged that suffocated ports and beaches with its slimy film.
Mucilage, also known by the viscerally accurate description of sea cord, is produced naturally by phytoplankton and is usually consumed by other marine life, including jellyfish and sea cucumbers.
Mustafa Sari, professor at the Maritime Faculty at Bandirma Onyedi Eylul University, blamed three triggers for causing phytoplankton to excrete an excess of the slimy substance that began in the fall: the surface temperature of the Marmara Sea, which has been steadily warming for two decades and is 2.5 degrees Celsius higher than the 40-year average; excess phosphorus and nitrogen from pollution and the natural stability of the Marmara, an inland sea.
Turkey has previously been plagued by mucilage, which bears some resemblance to the tidal wave of algae that spread in the Adriatic in 1989 – also caused by overproduction of microorganisms that scientists have linked to warming and pollution.
The problem first emerged in November, when Mr. Sari was flooded with urgent calls from local fishermen about the mucous membrane.
He asked a friend to investigate. The video that his friend brought back from a dive was alarming, he said. Large mucosal spheres were visible in the water, and at about 100 feet deep, the stage was completely black and without visibility.
Slime stuck to the fishing nets, making them too heavy to pull in, said Hakan Sevgi, 52, a member of a fishing cooperative. When the mechanical pulley on a boat broke, the crew spent seven hours pulling the nets by hand, a job that was to take half an hour.
Some crews were forced to jet their nets and now throw them only in shallow water for 30 minutes at a time, other fishing workers said.
During a dive this year, Mr. Sari that he found 30 sea cucumbers trying to climb down from the seabed, one of which clung to a seashell in an apparent attempt to rise above the mud.
On another dive, he found few left.
“We only saw three, which means the others died,” he said. The slime reduced the oxygen in the water, which is deadly to marine life.
December to March were lean times, but the fishing crews kept hoping that warmer weather would disperse the mucous membrane as before. But in April in Misakca, a small fishing village on the southern bank of the Marmara, disaster struck.
“The sandfish all turned white and died,” said Ahmet Kartal, 62. “Even the crabs died.”
“We are famous for our jumbo prawns here and now there is not even one,” he added. “For fifty years I have been a fisherman, and I have not seen anything like it in my life.”
The dead fish had gills clogged with mucous membranes, Mr Sari said, but the major unseen disaster was a collapse of the food chain.
“The biggest damage is marine biodiversity,” he said. “Those who are not mobile, coral reefs, mussels, fungi, mussels, these were strongly affected. They will return, but not in the short term. ”
Problems in Marmara had been brewing for years, said Erol Kesici, a hydrobiologist and adviser to the Turkish Society for Nature Conservation.
“There have been years of negotiations and warnings and nothing has been done,” he said. “The cause is household and industrial waste and untreated waste discharged into deep waters.”
The area around the sea is heavily populated – the city of Istanbul alone has grown to 16 million – with plans for further expansion. Sir. Kesici estimated that household waste may account for 40 percent of the pollution, with industry and shipping causing the rest.
President Recep Tayyip Erdogan, who has built his legacy on major construction projects, has a plan to build a canal through Istanbul to open an additional, toll-paid route for commercial shipping from the Black Sea to Marmara. Researchers have warned that the canal would cause major environmental damage to Marmara, but Mr. Erdogan and his ministers have countered these allegations.
“It is actually the opposite,” Transport Minister Adil Karaismailoglu said in a television interview last month. “When the clean water of the Black Sea mixes with Marmara, the water quality of Marmara improves.”
Parts of the Marmara area are already heavily industrialized, and Environment and Urban Planning Minister Murat Kurum said last month that the government had closed a fertilizer plant, a thermal power plant and three shipyards to reduce pollution when the slime crisis hit. The news.
It was not clear if the closures were temporary, but the minister said the government was also working to declare the sea a protected area.
The mucous membrane has hit Turkey in a difficult moment. Shattered by an economic crisis and exhausted by pandemic lockdowns, the Turks were desperate for some summer relief. Coastal communities reckoned with a lively tourist season, and fishing crews, hotels, and restaurants coped with busy months.
But faces were gloomy at the fish market in Bandirma one morning recently. Sales had been down for several months as the crews struggled to get a catch. But now boxes lay straight from the boats on the cement floor, while buyers stared and did not bid.
Customers were afraid to eat the fish.
“Ordinary people do not buy fish, so the price fell,” said Zihni Erturk, who owns a fishing trawler and a wholesale business. He said his businesses had been running at a loss since January.
Across the street from the market, the Moby Dick restaurant served only fish from the Black Sea, nothing from local waters.
In Canakkale, a popular tourist town on the Dardanelles, where the Marmara feeds into the Aegean Sea, holidaymakers looked into the harbor at the mucous membrane that had transformed the sea into the consistency of mussels.
Bound to action when the slime clogged ports and beaches, the government deployed municipal workers to try to pump it out. But scientists said the main problem was underwater and that there was no way to clean the seabed. The mucosa spreads to the Black Sea and the Aegean Sea, said Mr. Kesici, hydrobiologists.
He called for more inspections and stronger sanctions to prevent illegal dumping, which has been largely undisputed for years. Stinky rivers and canals still live in the ocean, he added.
But he and others called for far more fundamental innovation, including a moratorium for the rest of the century on waste disposal at sea.
“The burden on Marmara is too heavy,” Kesici said. “It can not carry all shipbuilding, tourism, traffic, even aircraft. It needs a break. ”