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At the nexus between Eastern Europe and Western Asia, the Black Sea ties together six countries: Turkey, Bulgaria, Romania, Ukraine, Russia, and Georgia. This true-color picture, taken by the Moderate Resolution Imaging Spectroradiometer on NASA's Terra satellite June 3, 2012, shows a summer phytoplankton bloom, coloring the sea with swirls of blues and greens. A sister sea, the Sea of Azov, to the northeast has colors that indicate the presence of the phytoplankton, mixed in with a bit of sediment as well. The bloom comes every summer, though its intensity varies depending on the nutrients available, water temperature, and other factors. This year the bloom came early and was going strong by mid-May, about two weeks before it was expected.

Image: NASA.

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