File:Phytoplankton world view from MODIS 2013.jpg

English: This map shows where tiny, floating plants live in the ocean. These plants, called phytoplankton, are an important part of the ocean's food chain because many animals (such as small fish and whales) feed on them. Scientists can learn a lot about the ocean by observing where and when phytoplankton grow in large numbers. Scientists use satellites to measure how much phytoplankton are growing in the ocean by observing the color of the light reflected from the shallow depths of the water. Phytoplankton contain a photosynthetic pigment called chlorophyll that lends them a greenish color. When phytoplankton grow in large numbers they make the ocean appear greenish. These maps made from satellite observations show where and how much phytoplankton were growing on a given day, or over a span of days. The black areas show where the satellite could not measure phytoplankton.