Two contrasting views of the Canadian phytoplankton bloom

This image features a phytoplankton bloom in northern Atlantic waters near Newfoundland, Canada, acquired 10 August 2002 by the MEdium Resolution Imaging Spectrometer (MERIS) sensor in two different manners. The right hand image is a qualitative estimation of the fluorescence signal emitted by phytoplankton. Clouds and lands have been masked and appear black. The left hand image is the corresponding ‘true colour’ image.

Phytoplankton absorbs energy from solar light in the blue spectral range. Part of this energy is re-emitted through fluorescence, in the red spectral range. The fluorescence signal seen on the right hand image is an excellent indicator of the presence of phytoplankton. MERIS has been specifically designed to observe these subtle variations in the waters of our planet.