Aerial view of a child sailing on a single-handed dinghy boat of the Optimist international class during a training session as the sea covered by sea snot, a thick slimy layer of the organic matter also known as marine mucilage, spreading through the Sea of Marmara and posing a threat to marine life and the fishing industry, in Istanbul, Turkey June 13, 2021. Picture taken with a drone. REUTERS/Umit Bektas