Cochlodinium polykrikoides
Cochlodinium polykrikoides (or Margalefidinium polykrikoides) is a species of red tide producing marine dinoflagellates known for causing fish kills around the world, and well known for fish kills in marine waters of Southeast Asia. "C. polykrikoides" has a wide geographic range, including North America, Central America, Western India, Southwestern Europe and Eastern Asia. Single cells of this species are ovoidal in shape, 30-50μm in length and 25-30μm in width. "Cochlodinium polykrikoides" is a highly motile organism. They are generally found in aggregations of 4 or 8 cell zooids. Chain length is known to be affected by  the presence of grazers and the inclusion of vitamins B,B and B. This species is also capable of mixotrophy, which makes them extremely persistent during a large algal bloom. "C. polykrikoides" exhibits diel vertical migration. "Cochlodinium" is thought to have a cyst-type overwintering stage in their life cycle. This process allows "C. polykrikoides" to produce a specialized cell that is non-motile. These cells aggregate and rest in certain basins until conditions allow for reproduction and colonies to form. Optimal growth conditions. "Cochlodinium polykrikoides" is a euryhaline species, capable of surviving a wide range of salinities. Growth experiments  have shown that "C. polykrikoides" can have greater than 0.3 divisions day in optimal growth conditions (25 °C, 34ppt). The growth range "C. polykrikoides" is 15 °C-30 °C, 20-36ppt and >30μmol m s irradiance. There has been no observed photo-inhibition for "C. polykrikoides" under high irradiance. Toxicity. "Cochlodinium polykrikoides" is a species that can produce allelopathic chemicals. These chemicals inhibit the growth of other phytoplankton taxa in the water column. The production of such toxins can play important roles in the formation of Harmful Algal Blooms. "C. polykrikoides" can also generate reactive oxygen species  which are lethal to both pelagic fish and shellfish even in low concentrations. Massive blooms. In late 2008 and early 2009 (November–February) there was a massive bloom of "Cochlodinium polykrikoides" in the Sea of Oman, off the coast of Oman in the Persian Sea. It was notable for being based on "Cochlodinium polykrikoides" rather than the "Noctiluca scintillans" ("Noctiluca miliaris") that had been more usual in the immediately previous years. The bloom resulted in massive dying off of fish, damage to coral reefs, and interference with desalinization plants. As climate change continues to affect the oceans, it is predicted  that harmful algal blooms (such as red tides caused by "Cochlodinium polykrikoides") will be more frequent in the upcoming years.