Phytoplankton in Bay of Arguin, Mauritania20.7N 17W
The bright green and turquoise waters of the Bay of Arguin, in Mauritania, are so colored by the growth of phytoplankton. These microscopic organisms are invisible to the naked eye, but tinge water with dazzling colors when they reproduce in great numbers.
The waters are greenest along the shores by the peninsula of Ras Nouadhibou (Cap Blanc). A tan coloring can be observed in the lower part of the bay, apparently from dust blowing off the mainland and the island of Tidra, the largest island in the bay.