Mucilage or Sea Saliva: What Is It?

Mucilage or sea saliva, although it appeared as a foam-like phenomenon covering the surface of the Sea of Marmara in the spring months of 2021, is actually a fundamental problem that leads to an ecological disaster. Despite having many causes, the root cause is ultimately the result of a wrong and distorted relationship established with the Sea of Marmara. Untreated sewage, industrial waste, excessive use of chemicals in agriculture, and waste from the maritime sector have exceeded the carrying capacity of the sea for years. At the same time, climate change has also raised sea surface temperatures. For these reasons, the natural balance structure of the Sea of Marmara has been disrupted.

Caddebostan Musilaj

Due to increased pollution, small plants called phytoplankton have rapidly proliferated to consume nitrogen and phosphorus, but they have not been able to fully consume these nutrients. The faster depletion of one of the two nutrient salts has put phytoplanktonic organisms under stress. Under this stress, phytoplanktonic organisms have started to produce organic secretions consisting of simple sugars. These sticky, transparent, and mucous secretions rapidly multiplied and led to the formation of long spiderweb-like structures on the surface of the sea. These structures are called "mucilage" or "sea saliva."

Initially, mucilage, not visible from the sea surface, is usually found densely at a depth of 15-20 meters in the sea. Fishermen notice the mucilage first because it covers their fishing nets, making it difficult for them to catch fish. As the nets become sticky, fishermen struggle to pull them.

The phytoplankton species causing the mucilage can vary depending on seasons and years. However, they are all short-lived, so they die quickly, and the dead phytoplankton combines with mucilage clusters. As these clusters rise to the sea surface, they carry particles, microplastics, and other pollutants in the water to the surface. These rising clusters come into contact with the air, dry, and form an elastic structure. These structures stretch when touched and can therefore form large masses that can be manually removed.

These mucilage clusters move, covering less-flowing bays, ports, and marinas, and can be transported by light winds. For example, a large area like the Gulf of Gemlik may appear covered with mucilage one day, but it can disappear without a trace the next day.

Extracted from Prof. Dr. Mustafa Sarı’s book “Mucilage: Elegy or Hope?”