Envisat's MERIS acquired this image on 3 May 2010 at a resolution of 300 m.
Envisat captures a crescent-shaped string of plankton in the North Sea weaving through the Scandinavian region. Norway (left) and Sweden (right), part of the Scandinavian Peninsula, are visible at the top, and Denmark is at bottom right.
The emerald green lake seen in Sweden is Vänern, the largest in the country..
The green water around Denmark is due to sediments being transported in the water.
Also visible (image centre) is Norway’s second largest fjord, Hardangerfjord at the north of Bergen.
The plankton, which forms the most abundant life in the oceans, is mainly composed of microscopic marine plants that drift on the surface of the sea or near it.
The plankton was nicknamed "the grass of the sea" because it is the staple food for a lot of other forms of marine life.
As the plankton contains pigments of chlorophyll for photosynthesis, these simple organisms play a role similar to terrestrial green plants in the process of photosynthesis.
Plankton is capable of transforming inorganic compounds such as water, nitrogen and carbon in complex organic materials. Because of his ability to digest these compounds, it is estimated that the plankton contributes as much as terrestrial vegetation to extract carbon dioxide from the atmosphere.
The chlorophyll used for photosynthesis by these microscopic organisms gives color to the waters of the ocean where they concentrate, which provides a means of detecting from space through sensors dedicated to the study of "ocean color" as the camera MERIS (Medium Resolution Imaging Spectrometer) Envisat.