The Effects of Salinity on Freshwater Copepods

Calcium chloride, among other sources of nonpoint source pollution, can be detrimental to aquatic species in rivers and streams. Calcium chloride (CaCl2) enters waterways primarily through runoff from impervious surfaces such as roads and storm drains in the form of road deicer. The purpose of this study was to examine the effects of salinity on freshwater copepod survival under laboratory conditions. Over a 7-day study period under lab conditions, 3 groups of copepods were exposed to 2 PSU (Practical Saline Units), 4 PSU and 6 PSU CaCl2 solutions. Survival rates were recorded and analyzed using Microsoft Excel running paired, one-tailed t-tests. It was hypothesized that as calcium chloride concentrations increased there would be a lower survival rate between days 1 and 3 when compared to days 3 through 7, relative to controls. Although the data did not support the hypothesis that survival rate would be lower within the first three days, increased salinity negatively affected survival rates in both time distributions.