Biological diversity of live food spectrum at Ambedkar Park, a sewage dominated area in downstream of river Gomti in Lucknow, India.

Abstract

Ambedkar Park, the National Monument on the bank of river Gomti situated in close proximity of Lucknow city receiving sewage, was identified for the present study. The water quality was poor with higher nitrate (26.02 mg l-1) and phosphate (2.55 mg l-). The pheo-pigments - chlorophyll-a, b and c were high with Chlorophyceae being the dominant phytoplankton group chiefly comprises genera Closteridium, Cladophora, Gonatozygon Cosmarium and Spharozosma. Zooplankton were low compared to phytoplankton. Cladocerans (Moinodaphnia, Ceriodaphnia) and copepodes (Cyclops) predominated the zooplankton fauna. The benthic fauna which serves the food for most of the bottom-feeding fishes was exceptionally rich. The high population density was attributed by worms i.e. oligochaetes (Lumbricillus, Limnodrillus, Liumbriculus, Chaetogaster, Nais and Tubifex) and Chironomus larvae. Tubifex and Chironomus were the organic pollution indicator organisms dominated the fauna. The pollution indicator Diptera (Culicoid larvae) group was also encountered. Shannon-Wiener Diversity Index (H) of benthic organisms was less than 1 for Oligochaeta, Diptera and Gastropoda indicating stressed environment. Though the benthic density was high, it may not contribute to food chain. Relatively low abundance of plankton population and biomass in spite of the high organic load of the system appears to the function of great infestation by pollutants suggesting extreme state of deterioration of water quality leading to the un-conducive ecological regime for fisheries development.