An HAB is the acronym for the term Harmful Algal Bloom, which describes blooms of a toxic nature. A bloom may be composed of more than one harmful or toxic species and this causes problems in research and monitoring, because they are difficult to identify individually. Germination of cysts is also dependant on salinity. After germination, the ambush dinoflagellate Pfiesteria piscida can vertically migrate or orientate itself towards prey, and this behavior is found in other species in response to light, salinity and nutrient supply. The life cycle permits the species to survive in unfavorable conditions and maintains population survival by genetic recombination.
Normal reproduction is asexual by cell division, which allows for rapid increase in cell numbers.
There are over 4400 marine phytoplankton species, but only between 50 and 60 are toxic. The difficulty arises when trying to identify toxic species, as some will not lead to a discoloration of the water, and some species that are not toxic, discolor the water and appear toxic. Life Cycle from a Cyst to a Bloom Figure 1. Other detrimental effects can be physical such as spines lodging in fish gills. A bloom can remain for several weeks to a few months.