The Ecology of the Zooplankton Community of a Small Quarry Pond with Special Reference to the Rotifers

Abstract

This study examines the effect of ecological factors within a small limestone quarry pond environment on the relevant biota. The author collected plankton samples over a period of six months in order to track the vertical distribution patterns within various species of zooplankton, while gathering quantitative data on seasonal physical/chemical changes of the pond. Specimens were collected using a net towed for a distance of 18-27m at depths of 0m, 0.5m, and 1.5 m. On completion, the net was removed from the water and organisms were concentrated into a 30ml vial. The sample was then poured into a different bottle and combined with 20ml of filtered pond water. Samples were transported immediately to the laboratory where all rotifers were live-counted using an A O Spencer binocular microscope. After completing the live count, the researcher preserved the sample and performed a second count using Congo Red stain at a later date. Crustaceans were immediately preserved and counted at a later date. The researcher observed a positive relationship between water temperature and the abundance of zooplankton, and a negative relationship between dissolved oxygen concentrations and planktonic organisms. Crustaceans did not seem to be affected by low concentrations of dissolved O_2. The researcher observed that pond depth affected the composition of the zooplankton populations. The researcher concludes that a combination of abiotic and biotic factors appear to play an important role in influencing and regulating zooplankton populations, lessening competition in the relatively shallow quarry pond.