EFFECT OF CARBONATE IONS (PH) ON THE GROWTH RATE OF RHINELLA MARINA TADPOLES

Abstract

Experiments were conducted to assess the effects of carbonate ions on growth, feeding
behaviour and survival in Rhinella marina tadpoles. Gosner stage 22 tadpoles were exposed to
different pH of carbonic acid, distilled water and pond water for duration of 4 weeks. Pond
water had a pH of 7 and distilled water of pH 6.5. Growth rate was significantly higher at
higher pH showing a significant difference between the growth in distilled and pond water with
carbonic acid. Time spent on feeding was significantly higher in distilled and pond water
indicating feeding to be partially responsible towards the growth rate. Survivorship was higher
for control animals as compared to those exposed to pH 5.5 and 6.0. It was also observed that
tadpoles in lower pH did not swim around a lot. At lower pH tadpoles faced a lot of stress
which hindered its development. Stress was brought about by desiccation and lower respiratory
rate since carbonic acid contains a lot of hydronium ions and less dissolved oxygen.