The major objective of the project was to determine the validity of using multispecies laboratory systems to evaluate the response of estuarine benthic communities to an introduced stress. In a 5-year period, experiments in Apalachicola Bay, Florida, and the York River, Virginia, sought to develop criteria for microcosm tests to evaluate the capacity of microcosms to model natural communities in the presence and absence of pollution-induced stress, and assess the validity of extrapolating test results of one location to another. Individual species response patterns in the microcosms were highly variable and seldom showed good agreement with patterns in the field. Species richness in the microcosms and field sites showed good temporal agreement and provided a conservative indicator of community response to a toxic stress.

"CR 812053."

The aim of this project was to evaluate the validity of using multi-species laboratory systems to assess the response of eatuarine benthic communities to an introduced stress. Over a 5- year period experiments in Apalachicola Bay, Florida, and the York River, Virginia, sought to (1) develop criteria for microcosm tests for evaluating the capacity of microcosms to model natural communities in the presence and absence of a pollution-induced stress, and (2) assess the validity of extrapolating test results from one location to another. Procedures for constructing, maintaining and sampling microcosms were tested and refined over the study period. A large number of laboratory and field tests were conducted synoptically over this period, including experiments in which microcosms and field sites were dosed with toxicants (mixed hydrocarbons in some and pentachlorophenol in others). We have investigated various methodologies for analysing and interpreting data derived from microcosm tests.