Sometimes (but not every year) in May-June the Black Sea turns… green.
Not just the greenish colour that large masses of water sometimes assumes, but a bright, almost ethereal bluish-green that mesmerises. What is going on?
The answer is simple and very much down-to-earth or, in this case, down to what's in the water. No, it is not pollution. It is the phytoplankton, a kind of migrating seaweed, that always lives in the Black Sea but that develops particularly rapidly at that time of the year.
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