The visualization on the right, derived using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard NASA’s Aqua satellite, shows monthly sea surface chlorophyll from July 2002 through February 2016. Chlorophyll is a proxy for phytoplankton abundance. Phytoplankton are microscopic algae: marine primary producers that turn sunlight into chemical energy that supports the ocean food web. Darker shades of green indicate more chlorophyll, more phytoplankton, while darker shades of blue indicate less chlorophyll and less phytoplankton. White represents the mode value of chlorophyll in the global ocean.