Phytoplankton are usually most abundant in this area when spring melting and runoff freshen the water and add nutrients just as sunlight is increasing.
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.
The milky green and blue phytoplankton developed where warmer, saltier coastal waters from the subtropics meet colder, fresher waters flowing from the south.