Heavy metals such as copper, cadmium, zinc and mercury have been shown in a variety of organisms ranging from mice to bacteria to reduce amino acid and sugar uptake in whole animal and in vitro tissue assays. However little knowledge of the effects of metal exposure on nutrient accumulation in the primary absorptive organ of bivalves, the hepatopancreas, exists. Copper exposure concentrations above 10 ppm showed significant accumulation in the tissues and coincided with significant reductions in glucose accumulation. This study focused on the compositional changes of macromolecules in two species of green algae, Dunaliella tertiolecta and Selenastrum capricornutum , in response to atrazine exposure. EC50 values for each species were determined in 96-hour toxicity tests.
Results indicate interspecific trends in addition to species specific changes.
These data suggest a common macromolecular response of increasing LMW molecules and decreasing protein in phytoplankton cells upon atrazine exposure. Future studies intend to focus on this trend to determine the mode of chemical transformation of these macromolecules as a result of atrazine exposure. Also, it is of interest to examine the changes in nutrition, growth, and reproduction in higher trophic levels grazing on atrazine-effected phytoplankton populations. Recently a novel cytophaga specie of bacteria, termed 41-DBG2, was isolated from Florida west shelf waters. A high-throughput bioassay was designed to quantify algicidal activity utilizing algal autofluorescence and a BMG fluorstar automated plate reader.