BIO ASSAY

The Bio Assay group conducts experiments to measure effects of the creek on living organisms. "Indicator species", a family of animals which are extremely sensitive to changes in its environment, are used to examine the health of the Arcade Creek in the form of the organism Ceriodaphnia dubia.

Changes in creek water quality become apparent in the survival rates of the C. dubia colony, thus use of this species allows for accurate measurement of biological responses around each site. By observing water effects on C. dubia and diatoms against controls, Bio Assay effectively monitors pollutants, namely toxins, in the creek and can effectively predict population declines of other species and help prevent them. 

Bio Assay collaboratively works with the Water Chemistry group by using their creek water samples to test in the laboratory. Initial tests include temperature, pH and electrical conductivity. A control group is created as a "wasser" solution (consiting of 80% Evion and 20% Arrowhead water). A recorded number of  C. dubia are then placed in vials containing creek water and "wasser" water, and are given light and time to react to their new environment. For a duration of two days, the C. dubia are counted and population changes are measured.

Large population decreases indicate the presence of toxins or an abnormally large or small pH levels. Early detection of declines in the creek's health through the observation of indicator species can be used as an effective method to promptly alert other studies so the project can restore the creek's health.