What Exactly is the ‘Sea Snot’ Plaguing Turkey’s Sea of Marmara?

Warming sea waters are thought to increase the frequency of such events in the future.

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Boat, Vehicle, Transportation
Image via Erhan Erdogan/Anadolu Agency via Getty Images

A major marine transportation hub that connects the Black and Aegean seas near Turkey was brought to a standstill in early June 2021 after the region experienced what is believed to be the biggest outbreak of “sea snot” in history. 

Held entirely within the borders of Turkey, the Sea of Marmara was plagued by a thick, slimy, and mucus-like sea snot — or mucilage — after the nation claimed sewage waste and pollution prompted a bloom. Described by NASA as a “rich soup of nutrients and life,” the Sea of Marmara has a unique structure that makes it particularly prone to large algal blooms. It is less saline than average marine environments, with fresher water near the surface and saltier water near the bottom, which makes it easier for small, plant-like organisms known as phytoplankton to grow. 

Rivers that feed into the Sea of Marmara bring with it agricultural runoff that can foster phytoplankton growth that can spur algal blooms. Paired with a high density of microorganisms like bacteria and cyanobacteria — or “blue-green algae” — in the water column, warming waters create an environment ripe for the development of mucilage. In addition to agricultural runoff and sewage pollution, experts warn that a changing climate may also make these algal blooms more frequent and dire.  A study published in 2009 in the journal PLOS One found that climate-driven sea surface warming may facilitate the spread of mucilage, which could, in turn, alter the microbial diversity across oceanic regions.

In an email to Snopes, Bayram Öztürk, president of the Turkish Marine Research Foundation (TUDAV), blamed the episode on insufficient wastewater treatment in the area — tbe waste of some 15 million people is discharged into the body of water. But the episode has been building for months, according to Peter Roopnarine, California Academy invertebrate zoology and geology curator. In an email to Snopes, Roopnarine said that the mucilage outbreak was almost certainly “helped by above-average warm temperatures in the Sea of Marmara and changing patterns of water circulation driven by global warming.”

Aside from impacting vessel transport in the Sea of Marmara and preventing some fishermen from working, mucilage has also reportedly killed large numbers of fish and other species that are dying from suffocation.

“There are no climatic ramifications, but there are climatic implications,” said Roopnarine. “Warming ocean temperatures in coastal areas, coupled with nutrient-rich run-off from agriculture and untreated or poorly treated municipal waste (e.g., sewage) means that the frequency, intensity and duration of mucilage outbreaks are increasing.” 

And the solution is not necessarily an easy one, Roopnarine said. 

“In the past, you simply rode them out,” he said, adding that officials would also plan to address the root problems. 

“But the size and duration of the more recent outbreaks, such as the one in Turkey, are economically very damaging. The microorganisms and the snot cause dissolved oxygen concentration to plummet, effectively suffocating many other marine organisms, such as fish,” he added. 

Öztürk told Snopes that there are currently operational efforts to clean the mucilage, however, it is neither efficient nor sensible to use a surface vehicle typically deployed. In addition to an assessment of the damage of the marine biodiversity started by TUDAV, a rescue diving team has started voluntary rescue efforts to save vulnerable marine species like corals in both the Sea of Marmara and the neighboring Sea of Aegean.

The Turkish government vowed to clean up the sewage outflow issue that was blamed for the mucilage outbreak. In addition to designating the Sea of Marmara as a marine protected area, the government has launched an initiative with researchers to conduct long-term monitoring studies of the region. 

“The most important thing, to do is to learn to live together with the beautiful sea next to you with respect,” said Öztürk. 

Recent Updates
  1. Update [June 10, 2021]: This article was updated to include comments from TUDAV.
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