Biological Assay "Bio Assay"
The Bio Assay study examines the health of the creek through an "indicator species" Ceriodaphnia dubia.
An indicator species is a species of animal that is extremely senstive to changes in its environment. Small changes in the water quality of the creek will result in drastic population declines in these two species. By observing the effect of creek water on Ceriodaphnia dubia and diatoms against controls, the Bio Assay study can effectively predict population declines of other species and help prevent them.
The Bio Assay study collects water from the creek and transports it to the laboratory. There, the temeperature, pH, and electrical conductivity of the water are initially tested. A certain number of Ceriodaphnia dubia are then placed in various vials containing creek water and are given light and time to react to their new environment. Control groups are then placed in a "wasser" solution. ("Wasser" consists of 80% Evion and 20% Arrowhead.) After three days, the Ceriodaphnia dubia are counted, and the population change is then recorded. Large population decreases indicate the presence of a toxin or an abnormally large or small pH. Early detection of declines in the creek's health through the monitering of indicator species can promptly alert other studies to the anomaly so the project can concentrate on restoring the creek's health at a specific site before it declines too far.
