Anacystis / Synechococcus
Synechococcus is a large contributer to planktonic primary production in freshwater and marine systems. The genus is also found on the surfaces of algae and plants, on algal films on sandy beaches, in outflow channels of hot springs and thermal pools, and growing within rocks.
The strain Anacystis nidulans was isolated in the United States and is important for experimental purposes. Several culture species are also very important experimentally. Anacystis or S. nidulans is mainly found in small water bodies of temperate zones. Some thermophilic species (i.e. S. bigranulatus, S. koidzumii, S. lividus, and S. vulcanus) prefer temperatures of about 70° C, and have been found in extreme habitats including hot springs in Yellowstone National Park and elsewhere in North America, Japan, Africa, and Indonesia. Some species are also found in the littoral zone and plankton of lakes and in swamps and soils.   In both fresh and marine waters, Synechococcus can be part of "whiting" events where suspended fine particles of carbonates are produced and in time increase sedimentary carbonate deposition. In late-summer, this precipitation of calcite can increase the exchange of organic carbon to lake sedimentation.