Global Warming Blankets Turkey’s Waters in “Sea Snot”

July 8, 2021 CATALYST Team

Turkey’s Sea of Marmara is covered in a thick blanket of mucus that is suffocating marine life. Global warming is likely the reason.

An aerial view of phytoplankton blooming in the Sea of Marmara in 2015. Right now, the sea is covered with a layer of “sea snot” that is harming marine life. NASA Goddard Space Flight Center. CC BY 2.0

Turkey’s Sea of Marmara is covered in a thick layer of a beige, viscous substance known as “sea snot” that is clogging fishing nets, killing corals and disrupting the breeding grounds of fish.

Sea snot—officially known as marine mucilage—comes from phytoplankton, with high levels occurring as a result of prolonged warm temperatures, calm weather and abundant nutrients in the water. An abundance of nutrients like nitrogen and phosphorus lead to a boom in the phytoplankton population. In normal amounts, phytoplankton are an important part of the ocean’s ecosystem; they are microscopic organisms that exude oxygen. During a population boom, however, phytoplankton can become harmful; under conditions of stress they expel mucus that can accumulate on the surface, creating sea snot that can grow to cover many square miles of ocean.

Typically, sea snot on its own is not harmful. In fact, research shows that some deep-sea organisms depend on sea snot to stay alive. It only becomes dangerous when sea snot of large amounts begins to host E. coli and other bacteria and viruses, or forms a layer that covers the surface of the ocean, as in Turkey.

When the sea snot is thick enough to cover the water’s surface, it can act as a blanket, suffocating the marine life below. Immobile organisms like corals are especially vulnerable to damage from sea snot because it can wrap around them, cutting off their ability to breathe or feed. Blankets of sea snot such as the one in Turkey can set off a cyclical chain of events wherein the sea snot suffocates sea creatures, leading to mass die-offs. This in turn leads to mass decomposition, a process that sucks even more oxygen out of the already depleted water, making it more inhospitable for marine life.

Sea snot is not a new phenomenon; it has been periodically blooming in the Mediterranean Sea since the 18th century. However, the frequency and extent of sea snot occurrences along Turkey’s coast since 2007 are unusual, and scientists suggest that global warming may be to blame. Phytoplankton thrive in warmer waters. The average seawater temperature in the Sea of Marmara has increased by 2-3 degrees C since preindustrial times. While that may not seem like a lot, the warmer waters are enough to make a major difference in the phytoplankton populations of the sea, which is already rife with nutrients from wastewater. The higher temperatures make the sea even more hospitable to phytoplankton, which leads to disruptive sea snot events like the one Turkey is currently experiencing.

While the sea snot problem has recently gotten international attention, it has been negatively impacting Turkey’s fishing industry since December, when the bloom began. Fishers have been unable to cast their nets without them getting caught in the sticky mucus, and many of the creatures they do manage to catch are dead, their gills clogged with sea snot.

Dr Neslihan Özdelice, a marine biologist at Istanbul University, urged for a focus on preventing overfishing and limiting waste water discharges into the sea, two factors that scientists have identified as contributing to the sea snot phenomenon. Ultimately, the layer of sea snot that is currently covering the Sea of Marmara, disrupting fishing and threatening biodiversity, is a symptom of a problem that needs to be addressed globally. Major sea snot blooms are an easily visible example of climate change. Global cooperation is necessary to address the root of the problem by working towards mitigating climate change and global warming.