‘Plankton explosion’ turns Istanbul’s Bosphorus turquoise

Transformation of the usually blue waters of the Bosphorus is not caused by pollution, say scientists

A sudden change in the colour of the Bosphorus Strait that divides the continents of Europe and Asia in Turkey's largest city Istanbul has surprised residents, with scientists putting it down to a surge in a species of plankton across the Black Sea.

The sudden transformation of the usually blue waters of the Bosphorus to a milky turquoise since the weekend had alarmed some residents.