Cyanobacteria are one of the oldest forms of life, having been found in fossils from 3.5 billion years ago. Also known as blue green algae or Cyanophyta, they are prokaryotes - single celled organisms with little internal structure - and grow in colonies that form filaments, hollow balls or sheets. (Little Things Matter A lot, 2005)They are mostly found in fresh water or marine water zones, but also in soils, and have also adapted to grow in extreme condition like deserts, hot springs, brine pools and salt ponds. (Cyanobacteria, n.d.)
People originally named Cyanobacteria blue green algae. Algae, however, are eukaryotic organisms, whereas further studies have shown that Cyanobacteria are prokaryotes. A better name for them is blue greens, but this remains a common mistake even today. Although they are named blue greens because they have color pigments, such as Phycocyanin, in them for photosynthesis, they can also have different colors. (Little Things Matter A lot, 2005) During the process of photosynthesis, Cyanobacteria convert sunlight into energy. At the same time, they release oxygen. This process was incredibly important in the history of life on earth. (Static Evolution, 1994)Cyanobacteria have helped the earth in three ways: by releasing oxygen, by fixing nitrogen and by capturing sunlight as energy that other species feed on, especially in the ocean.
Introduction
http://www.tinkerfish.com/aquarium/freshwater/
http://www.algae.info/bgreenbloom.jpg
