Physico-chemical characteristics of Surajkund water body in Varanasi (UP) were monitored. High levels of nitrogen (N), phosphorus (P), calcium (Ca), potassium (K) and sodium (Na) indicated that pond was eutrophic. However, contrast to nitrate, ammonia-nitrogen was high in summer and low in winter. The high concentrations of sodium in summer stimulated uptake and transport of CO2 and HCO3...