Scientists’ alarm is growing in Turkey over the massive and uncontrolled diffusion in the Sea of Marmara, south of Istanbul, of marine mucilage, a collection of organic matter that is potentially very harmful to the ecosystem. According to experts, the phenomenon is mainly linked to climate change and pollution due to incorrect waste disposal in the area, around which about 25 million people live. A thick layer of this gelatinous substance, also called sea mucus, now covers the waters in an evident way, threatening the survival of several species. “The Sea of Marmara has become a dead sea. We must act as soon as possible”, is the alarm raised by Erol Kesici, scientific advisor of the Turkish Association for the Conservation of Nature. In recent weeks, the authorities have launched some water cleaning initiatives, but for experts these are buffer measures that cannot solve the structural problem.