012236 Tajagopal T;Thangamani A;Archunan G (Animal Science Dep, Bharathidasan University, Tiruchirappalli-620 024, Email: deer_raj@yahoo.co.in) : Zooplankton species richness and diversity in three perennial ponds of Virudhunagar district, Tamilnadu. Pollut Res 2008, 27(1), 49-58.
Plankton, as a first step in trophic cascades of water bodies, can be a good indicator of trophic states, considering that every environmental change affects this community and many species of this community are sensitive to changes, and that they response very quickly. Tries to assess the zooplankton species richness, diversity, and evenness and predict the state of three perennial ponds according to zooplankton data and physico-chemical parameters. A total of 47 taxa were recorded: 24 rotifers, 9 copepods, 8 cladocerans, 4 ostracods and 2 protozoa. Maximum numbers of zooplankton population were recorded in Chinnapperkovil pond (47 species) followed by Nallanchettipatti pond (39 species) and Kadabamkulam pond (24 species). Among the rotifers, Branchionus sp. is abundant. Diaphanosoma sp. predominant among the cladoceras. Among copepods, numerical superiority was found in the case of Mesocyclopes sp. Cypris sp. repeated abundance among ostracoda. Study revealed that zooplankton species richness (RI & R2) was comparatively higher (RI: 4.39 ± 0.11; R2: 2.13 ±0.04) in Chinnapperkovil pond. The species diversity was high in (H': 2.53 ± 0.03; NI: 15.05 ± 0.49; N2: 15.75 ± 0.47) Chinnapperkovil pond as compared to that other ponds. The water samples were analyzed for temperature, pH, electrical conductivity, alkalinity, salinity, phosphate, hardness, dissolved oxygen and biochemical oxygen demand. Higher value of physico-chemical parameters and zooplankton diversity were recorded in Chinnapperkovil pond as compared to other ponds. The zooplankton population shows positive significant correlation with physico-chemical parameters such as, temperature, alkalinity, phosphate, hardness and biochemical oxygen demand, whereas negatively correlated with rainfall and salinity. This work revealed that by the presence of certain species like, Monostyla sp., Keratella sp., lapadella sp., Leydigia sp., Moinodaphnia sp., Diaptomus sp., Diaphanosoma sp., Mesocyclopes sp., Cypris sp., and Brachionus sp., is considered to be biological indicator for eutrophication.
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