Algal Bloom in Norway
Swirls of blue-green algae fill the sea off the northwest coast of Norway on 6 July 2005 in this image captured by the MERIS sensor.
A "bloom" of these microscopic organisms is actually a population explosion as their numbers grow exponentially as a result of increased temperature and ample nutrients in coastal waters. Thus, these summer algal blooms, once a rare phenomenon, have become more frequent as northern waters have warmed in recent years and the level of pollutants such as phosphates has increased.
Summer blooms in warm waters are quite different from spring algae blooms in cold waters. The micro-organisms colouring the water may not in reality be algae at all but a form of microscopic bacteria known as cyanobacteria. Some species of cyanobacteria are toxic to animals, fish, and shellfish.