Nutrient-plankton interaction with a toxin in a variable input nutrient environment

Phytoplankton are microscopic plants that live in the ocean, sea or lake. Through photosynthesis, phytoplankton are responsible for much of the oxygen present in the Earth’s atmosphere. They convert inorganic materials into new organic compounds by the process of photosynthesis [14]. Hence the stocks of these tiny planktonic algae play a significant role for marine reserves and fishery management. In terms of numbers, the most important groups of phytoplankton are the diatoms, cyanobacteria and dinoflagellates, although many other groups of algae are also very populated. Pollution of freshwater and marine systems by anthropogenic sources has become a concern over the last several decades. Organic (e.g. triazine herbicides) [1, 16, 17, 18, 25, 26] and inorganic compounds (e.g. heavy metals) [6, 13, 17, 18, 19, 23, 24] both may have harmful effects to the organsims. For example, samples taken from the inner harbor of the Waukegan area, located in Lake County, Illinois, on the west shore of Lake Michigan, have shown that photosynthesis of the green algae Selenastrum capricornutum is inhibited due to pollutants originating from industrial and recreational sources.