ABSTRACT
Plant communities are important to the functioning of freshwater, estuarine, and marine ecosystems. Algae associated with the plankton and periphyton form the base of most food chains, produce oxygen, and are important in the cycling of nutrients. Vascular plants or macrophytes provide habitat and shelter for many forms of animal life in near-coastal and freshwater environments and are more important in photosynthetic activity and constitute a larger biomass in rivers than planktonic algae. Toxicity tests conducted with marine microalgae and chemicals are similar to those with freshwater microalgae; static tests are conducted with rapidly growing and easily cultured species. An algal toxicity test begins when the test medium is inoculated with exponentially growing algae obtained from a laboratory culture. A key consideration in algal toxicity tests is the choice of the test species, as this decision can influence the test results.
