Phytoplankton are usually most abundant in this area when spring melting and runoff freshen the water and add nutrients just as sunlight is increasing.
This image shows a colorful bloom of phytoplankton in the Black Sea on June 4, 2008, along the southern coast near the Turkish cities of Sinop and Samsun. The natural-color image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. Loops and swirls of blooming phytoplankton follow the coastline, while farther out in the open waters (upper right), the blooms become more spread out. The greenish plumes hugging the coast from Sinop westward to just beyond Samsun may be river plumes. River plumes can contain nutrients that stimulate phytoplankton blooms, but they may also contain sediment and organic matter that can color the water.
The northern and western highlands of Scotland were still winter-brown and even dusted with snow in places, but the waters of the North Sea were blooming with phytoplankton on May 8, 2008, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite passed over the region and captured this image. The tiny, plant-like organisms swirled in the waters off the country’s east coast, coloring the shallow coastal waters shades of bright blue and green.