False-colour satellite image of the Atlantic Ocean off the northeast coast of South America, showing the distribution of phytoplankton in the water. The colours represent varying phytoplankton densities from red (most dense) through yellow and green to blue (least dense). Land areas are black and regions where no measurements were possible are coloured grey. The phytoplankton distribution is dominated by the influence of the Amazon (right) and Orinoco (left) rivers, which discharge nutrient-rich waters into the ocean. The image was produced from data acquired by the Coastal Zone Colour Scanner on NASA's Nimbus-7 satellite.