WATER QUALITY AND LIFE-HISTORY PARAMETERS OF DAPHNIA CARINATA (DAPHNIDAE : CLADOCERA) UNDER LABORATORY CONDITIONS

Abstract

The life-history and population of aquatic crustaceans mainly depend on water quality. This study is aimed to test the hypothesis that water hardness and alkalinity affect the life-history parameters of Daphnia carinata. Experiments were carried out accordingly in laboratory conditions. There was a significant reduction in the growth of daphnids reaching up to a 14.5% as compared to high hardness and alkalinity. There were also delayed reproduction, increased body length during first reproduction and reduced number in first brood and, consequently, a 36.6% reduction in total fertility, to daphnids reared at high hardness and alkalinity. The impaired
growth and reproduction at hardness and alkalinity levels was likely a consequence of increased salt concentrations, and not due to changes in the feeding activity. This study raises concerns about the effects of environmental degradation and increasing acidity in the surrounding medium which is evident in the form of acid rtain etc due to increasing pollution. The decrease in populations of D. carinata and similar other planktons will affect the structure of aquatic ecosystems.