Awasthi and Tiwari (2004) studied the seasonal trends in abiotic factors in lake Govindgarh, Rewa, Madhya Pradesh. An inverse relationship was observed between dissolved oxygen and temperature. The lake was perennial and alkaline in nature. The parameters found to show marked seasonal variations include temperature, transparency, pH, dissolved oxygen, free carbondioxide, alkalinity, calcium, chloride, nitrite and phosphate. The study reveals that Govindgarh lake was polluted.

The impact of urbanization on Bellandur lake, Bangalore was studied by Chandrasekhar et al ., (2003). The study shows higher values of alkalinity, BOD and COD and low levels of dissolved oxygen indicating the polluted nature of the lake. The urbanization of surrounding areas had let to the discharge of domestic sewage and industrial effluents into the lake, which contributed to the observed trends.

Maruthanayagam et al., (2003) studied the zooplankton diversity along with the physicochemical parameters in Thirukkulam pond, Mayiladuthurai, Tamilnadu. Higher density of zooplankton was recorded during the rainy season, with copepods forming the dominant group followed by cladocera, rotifera and ostracoda. Five species of rotifera, four species of cladocera and three species each of ostracoda and copepoda were recorded. The Ostracods even though tolerate wide range of ecological factors, did not occur in polluted waters. The lower density of zooplankton during the summer months than in the rainy months was attributed to higher temperature, decrease in the nutrients and thereby the phytoplankton population.

Pandey et al., (2004) studied the seasonal fluctuation of zooplankton community in relation to physicochemical parameters in river Ramjan of Kishanganj, Bihar. The collections were dominated by rotifera, followed by cladocera and copepoda. Rotifera showed a negative correlation with pH, dissolved oxygen and transparency and copepods showed negative correlation with water temperature, nitrate and phosphate. The cladocerans also revealed negative correlation with pH, transparency and phosphate. This indicates several abiotic factors exert a considerable influence on the zooplankton abundance.

The physicochemical and zooplankton analysis of the Shendurni river, Kerala was studied by Sahib (2004). The dissolved oxygen levels were observed to be highly saturated and a direct correlation between dissolved oxygen level and zooplankton populations were observed.

Chakrapani (1996) compared the zooplankton diversity and physicochemical analysis of both urban and non-urban lakes. 19 urban and 24 non-urban lakes were selected for the study. The zooplankton diversity of some of the urban and non-urban lakes was compared with the earlier study. The changes in the populations have indicated the influences of pollution on these lakes. Biological analysis indicated that lakes such Anekepalya, Bellandur, Chilkkahulimam, Harohalli, Kengeri, Kalkere, Nagavara, Nelamangala, Puttenahalli, Rachenahalli, Rampura, Tavarakere, Ulsoor, Varthur, Vengaiah, Yellahehalli, and Yellamallappuchetty were threatened ecologically and unsuitable for human usage.

Studies on the zooplankton diversity in the evaluation of the pollution status of water bodies were carried out by Khan and Rao (1981). The potential effects of thermal pollution, nutrient enrichment in eutrophication, interaction of ions, toxic substances like heavy metals, halogens, solids, reducing agents, and radioactive wastes on aquatic protozoan communities had been studied. Rotifers were found to be more sensitive to pollution than other groups of zooplankton. Among crustaceans, cyclopoids and cladocerans were found to be associated with increasing productivity. The ratio of calanoids to cyclopoids plus cladocerans was found to be good indication of trophic condition and valuable index of pollution.

Mahajan (1981) made preliminary studies of the identification of species among the zooplankton community, which could serve as indicators of different types of pollution. Species of zooplankton which could serve as indicators of thermal pollution and stress pollution, Eutrophication, Heavy metal pollution, Pesticidal pollution and miscellaneous pollution activities were studied. Toxicity tests conducted for the selected species indicate, different groups of zooplankton were found to be sensitive to different types of pollutants.

Chakrabarty et al., (1959) studied the plankton and the physicochemical conditions of river Jumna at Allahabad. The zooplankton community was represented by rotifera, protozoa, copepoda, cladocerans and ostracoda. The rotifers were found to be dominant group followed by protozoa and crustaceans. The collections were made during the early morning, midday and in the night and vertical migration was noticed by the presence or absence of certain forms during the morning, midday, and night collections of the same day. The study shows that water quality, turbidity and temperature have an influence on plankton populations.

The zooplankton diversity of four village ponds - Kadagrahara, Karpur, Side Hoskote and Chembenahalli in Bangalore district of Karnataka, was studied by Rao et al., (1982). Zooplankton were found to be abundant when compared to phytoplankton. Protozoa were found to be richer in variety where as some of the rotifers were found to be high in numbers in all the ponds and poorer representation of the cladocerans in Kadagrahara, Chembenahalli and Karpur ponds because of the high concentrations of ammonia (10-20 mg/L).

Plankton abundance in relation to physicochemical features of Mancharibele reservoir in Bangalore district was studied by Sukumaran and Das (2002). Zooplankton population was found to comprise of four major groups, which include protozoa, rotifera, cladocerans and copepoda. Protozoa were represented by Arcella, Centrophyxis and Difflugia species. However, the numbers were found to be less. Rotifers were found to be the second dominant group and were represented by a large number of species and genera. Cladocerans density was less when compared to rotifers and six species were observed. Copepods were found to be represented mainly by Diaptomus and Cyclops nauplii. They were found to be the dominant group among the zooplankton. The optimal temperature requirement varied for different groups of zooplankton suggesting their abundance in different seasons. The high chloride content and temperature were also found to favour zooplankton abundance.

A study on plankton and a few physicochemical features of Milghatta and Hutcharayangere tanks in the Malnad region of Karnataka was done by Sukumaran et al., (1984). The zooplankton encountered include Protozoa (3.54%), Rotifera (2.23%), Cladocera (3.15%), and Copepoda (15.41%) in Milghatta tank. The population in the Hutcharayankere tank was very low compared to that of Milghatta tank. In Hutcharayankere tank, Copepods where the dominant groups (16.54% of the total plankton), whereas other groups were rare in occurrence. Since the tanks were low in nutrients these tanks were oligotrophic and hence less productive. The low nutrient content in these tanks to the red soil present in the region, which had low nutrient and organic matter, and also due to aquatic vegetation that takes up nutrients.

Rao et al., (1982) studied the physicochemical parameters and zooplankton diversity of perennial tank, Hutchammankere located near Anekal in Bangalore district for the period of two years. Zooplankton community constituted of Protozoa (43.09%), Rotifera (39.29%), Cladocera (2.22%), Copepoda (15.21%), Ostracoda (0.80%) and Nematodes (0.18%). Increase in temperature was found to be favourable for zooplankton multiplication. Turbidity was found to affect phytoplankton production but had less influence on zooplankton. Thus an inverse relationship was obtained between phytoplankton and zooplankton in relation to turbidity. An inverse relationship was observed between phytoplankton and zooplankton because of the grazing effects of zooplankton over phytoplankton.

A study on the physicochemical limnology and productivity of Jaisamand lake, Udaipur was conducted by Sharma and Sarang (2004). The zooplankton density for Rotifers, Cladocerans and Copepoda varied from 13 to 233 organisms per liter. Comparison with earlier work shows of 49 species of zooplankton in 1980-82. Present record of 21 species indicates the decline in the diversity of zooplankton in the Jaisamand lake. A positive correlation of water clarity with pH, total alkalinity, Electrical Conductivity, net primary productivity and gross primary productivity was observed whereas, a negative relationship was found for free carbondioxide and nitrate. The decline in zooplankton population in the lake was due to the predatory effect of fish species tilapia.

Hydrobiological studies of lake Mirik in Darjeeling, Himalayas was done by Jha and Barat (2003). Qualitative analysis of zooplankton was carried out and cladocerans and copepods were the groups, which were found to represent the zooplankton community. Among the copepods Cyclops was found to be the most abundant zooplankton followed by Phyllodiaptomus and among the cladocerans Moina , Daphnia , Bosmina were recorded. The pH of the lake was found to be acidic in nature and other physicochemical parameters and plankton analysis confirmed that the lake was polluted due to contaminants let into the lake, though the values were diluted due to heavy monsoons. Thus the study indicates that the lake cannot be used as a scarcity alternative for drinking water supply

Sunkad and Patil (2004) assessed the water quality of Fort lake Belgaum, Karnataka. Zooplankton were represented by four groups, which include Rotifers, Cladocerans, Copepods and Ostracods. Rotifers were found to contribute to the zooplankton richness of the Fort lake accounting 52.38% followed by copepoda 26.5%, Cladocerans 16.45% and Ostracods 4.67%. The dominance of rotifers in the lake was due to the continuous supply of food material which inturn indicates the eutrophic nature of the lake. The level of phosphates in the lake was high (7.2 to 13.6 mg/L) due to the entry of sewage into the lake and hence supported the cause of eutrophication. Hence the lake was highly unsuitable for drinking water purposes.

Seasonal distribution of the population structure of zooplankton was studied in connection with physicochemical parameters in an experimental perennial fish culture pond in Calcutta, West Bengal by Sarkar and Choudary (1999). 17 species under 13 genera of zooplankton was observed. Rotifers expressed superiority in the species richness followed by cladocerans and copepods. However, the cladocera was found to be the most abundant group followed by copepods and rotifers. Shannon index for zooplankton was found to vary in the pond. A significant multiple correlations involving the fluctuations of zooplankton number and concentration changes of dissolved oxygen, temperature, total alkalinity, total nitrogen, phosphate and pH were found. Thus, the study confirms the influence of these abiotic factors on zooplankton population.

Zooplankton community structure and its relation to physicochemical parameters in lake Tasek, a tectonic lake in Garo hills, India was investigated by Das et al., (1996). Shannon diversity index (H'), Evenness index (J) and Species Richness index (S) were calculated. About 18 taxa of zooplankton were recorded of which 3 each belonged to Copepods and Cladocerans, 10 to Rotifers and 2 to protozoa. The correlation analysis among diversity, evenness and richness values revealed close relationship between H' and J, but neither was related to S. Evenness (J) was negatively correlated to zooplankton density, but Species Richness was positively correlated. Zooplankton densities were found to exhibit significant positive relationships with phytoplankton densities, pH and alkalinity. Low values of conductivity, alkalinity, nitrates and phosphates found in lake Tasek were suggestive of its oligotrophic nature. The abundance of copepods also indicated the stable environmental conditions. Since zooplankton densities exhibited the significant positive relationships with phytoplankton densities, pH and alkalinity, these variables were the important factors governing the abundance of zooplankton in lake Tasek.

Raut and Pejaver (2003) studied the rotifer diversity of three macrophytes infested lakes from Thane city, Maharashtra that include Lake Ambegosale, Lake Rewale, Lake Makhmali. Rotifera with 19 species belonging to 9 genera were obtained. This was compared with uninfested lakes in which only 10 species belonging to 6 genera were obtained. The study shows that the macrophytes help to increase the diversity of rotifers and rotifer population varied between mesotrophic and oligotrophic lakes.

Zooplanktonic diversity of 6 ponds of Durg-Bhillai city, Chhatisgarh state was studied by Anil kumar et al., (2004). Rotifers and copepods were found to be predominant group. The rotifers were represented by 5 species of Brachionus and 1 species of Tesdinella , indicating eutrophicated status. Copepods were mainly dominated by Mesocyclops species and cladocerans, the least abundant group comprise Moina species and Ceriodaphnia species. Ostracods were also observed in their collection with Cypris species being the dominant organism. Ostracods were also found to show diurinal variation between day (206 organisms/m 3 ) and night samples (555 organisms/m 3 ). The predominance of rotifers and copepods indicate the nutrient availability in these ponds.

Das (2002) studied the dynamics of net primary production and zooplankton diversity in brackish water shrimp culture pond in northern part of Ganjam district, Orissa. Significant negative correlation was noticed between net primary production and zooplankton population. Copepods and rotifers were found to be the dominant groups among zooplankton. The zooplankton population varied with different seasons of the year with rainy and summer seasons showing the minimal density in zooplankton population.

Patil and Shrigur (2004) studied the morphology and identification characteristics of four copepods species namely Thermocyclops crassus, Mesocyclops leukarti, Apocyclops royi (order cyclopidae) and Eudiaptomus gracilis (order Calanoida and family Diaptomidae). The study was conducted in government fish farm, Goregaon, Mumbai. Eudiaptomus gracilis and Apocyclops royi were the first record for Mumbai.

Zooplankton diversity in five major coalfields areas in Jharkhand was studied by Saha (2004). Seventy species of zooplankton were recorded in this study. Cladocerans and rotifer were abundant groups (9 species each) followed by seven species of copepoda, and one species of ostracoda. The species were resistant to coal dust and indices for richness, diversity and evenness of the zooplankton did not present a trend in the dynamics of the plankton community. The evenness (J) showed insignificant relationship with species diversity index (H'), species richness (S) showed negative relationship with species diversity index values. The overall diversity of plankton was low due to high alkalinity of water due to fly ash deposition.

Chakrapani (1996) studied the plankton diversity of Sixty one lakes of Bangalore and report zooplankton falling under five major groups - protozoa, rotifera, cladocera, copepoda and ostracoda. Fourteen forms of protozoa, twenty nine forms of rotifera, six forms of cladocera, four forms of copepoda and five forms of ostracoda were recorded. On the overall sixty two forms of zooplankton were observed including five unidentified forms. The appearance of intermediary stages of Rabditis species in five lakes indicates the presence of potential human parasites.

Venkataraman et al., (2001) studied the faunal diversity of the wetlands in the Indian Botanical Garden, Haora, West Bengal. About 55 species of zooplankton belonging to 6 different groups - Hydrozoa (1 species), Copepoda (4 species), Ostracoda (5 species), Cladocera (38 species) Conchosraca (1 species) and Rotifers (3 species) had been observed. Larger Cladocerans, Daphnia species were not recorded in the study because of high predation pressure by fish and macroinvertebrates. Due to increasing utilization of wetlands of Indian Botanical Gardens for pisciculture and due to other anthropogenic interferences, the bioaquatic environments of these lakes had been rapidly altered. The faunal diversity was dependent on the plants as well as the size of the wetland concerned and inversely related to anthropogenic activities.

Pandit (1999) studied the zooplankton diversity and analysed the general trophic structure of the plankton community in five different wetlands of Kashmir. Among the 141 species of zooplankton observed were 61 species of protozoa, 29 species of rotifers, 35 species of cladocerans, 13 species of copepoda and 3 species of ostracoda. The scheme depicting the generalized type of food web prevalent in the wetland with respect to zooplankton had been formulated. The study revealed the gradual decrease in the number of zooplankton species and increased primary productivity due to eutrophication. The eutrophication affected the species composition, biomass and structure of zooplankton community thus leading to rapid increase in the both density and biomass of phytoplankton community as compared to herbivores.

Alam and Khan (1998) reported the first record of cladoceran Leydigia acanthocercoides (Family: Chydoridae) from Aligarh, Uttar pradesh. 9 species belonging to 6 genera had been recorded. The female organism of Leydigia acanthocercoides had been described giving the characters of taxonomic importance. The species were found to inhabit the aquatic weeds in polluted ponds.

Sinha (2002) reported the first record of cladoceran Bosmina tripurae from wetlands of Botanical gardens, Guwahati, Assam. The species was found to occur in association with other cladocerans namely Daphnia species, Ceriodaphnia species, Moina species, and Simocephalus species. The female organism of Bosmina tripurae had been described giving the characters of taxonomic importance. The study reveals the species extension in Assam, which had earlier been reported from Tamilnadu.

Banik (2002) reported 2 species of genus Collotheca ( Collotheca tetralobata and Collotheca hexalobata ) from the littoral regions of shallow water wetlands of Agartala, Tripura. Collotheca tetralobata was reported to differ from closely resembling Collotheca ornata by the presence of 2 longer lobes and 2 shorter lobes, paired lateral antennae, very long holdfast and interlobal cilia and the absence of pentagonal arrangement of 5 short lobes and very reduced holdfast. Collotheca hexalobata is characterized by the presence of 6 lobes, longer holdfast and it's broad and oval base and by the absence of pentagonal arrangement of tubular lobes, interlobal cilia, greatly reduced holdfast with small and round base and a transparent lorica. The species, its ecological characteristics like physicochemical conditions of water, plant substrata preference and seasonal occurrence had been recorded. The species mostly occurred during summer and only one individual was recorded during winter.

Freshwater cladocerans of Andaman and Nicobar islands was studied by Venkataraman (2000) in a total of 106 freshwater habitats which include ponds, marshes, reservoirs, rice fields, dams, streams, rainwater pools. The zooplankton samples were collected by dragging the net close to the bottom among vegetation and clear water. 38 species belonging to 21 genera of 5 families were observed of which 24 were chydorids and 14 nonchydorids. The selected 7 stations were compared by the Sorensen index of similarity and Koch index of biotic diversity. The indices from Andaman group of islands were found to be high which inturn indicated the small number of species involved and their wide distribution. However, the indices for the Nicobar group of islands were found to be comparatively lower because of the influence of erratic occurrence of eurytropic species such Moina micruta , Ceriodaphnia cornuta and Macrothrix spinosa . The cladoceran proliferation was found to be affected during rainy season.

Siddiqi and Chandrasekhar (1996) reported the new distributional record of Trichotria tetratis and Daphnia lumholtzi from Kolleru lake Andhra pradesh. Trichotria tetratis occurred in waters of high conductivity (130mS/m) and higher total alkalinity and total hardness. The phosphorus and other heavy metal ion were also high in the region where the species had been recorded. Thus, Trichotria tetratis could be used as a pollution indicator for eutrophic conditions as the species had also been reported from sewage polluted tank.

Venkataraman and Das (1995) reported 2 species of cladoceran, Sida crystallina and Acroperus harpae from Tripura state. Diagnostic characters of both the species had been described. Body of the Sida crystallina was cylindrical and oblong. Antennules short, truncate with short flagellum. Post abdomen narrow anteriorly with 14 lateral spines and lateral setae above. Claw has four basal spines with row of setae. Body of Acroperus harpae was evenly rounded dorsally, head keel present, maximum height in the middle. Posterior margin was convex and slightly shorter than the maximum height of the body. Rostrum blunt, with antennules not reaching the apex of rostrum. Ocellus was small and situated closer to the eye than to the apex of rostrum. Post abdomen long with very small spines and 13 to 15 groups of lateral setae that decrease in size proximally. Claw was long and slightly curved dorsally.

Venkataraman and Das (1994) reported the occurrence of Moina weismanni , which was the new record for West Bengal. The male and female organisms of the species had been described. Body size of Moina weismanni was 1.23mm and it possesses a supraocular depression and broadly rounded head, which had been reported as the characteristic features of this species. The post abdomen has a row of 7 9 feathered teeth along with a bident tooth on either side. The dorsal surface of the post abdomen is also provided with small spines. The claw is long with basal dorn at the proximal region. This species was found as an extension to Northeastern India apart from earlier reported regions of Gujarat and Tamilnadu.

Venkataraman (1999) studied the freshwater cladocera of southern Tamilnadu. Plankton net was dragged among the vegetation close to the bottom of the shallow waters in marshes to collect zooplankton. Oblique hauls were taken from the shores of manmade reservoirs and ponds. The study revealed the occurrence of 46 species of cladoceran belonging to 23 genera and 5 families. 5 species of Daphnia were observed, which were considered as limnetic cladocera found in temperate region. The study shows that temperature plays an important role in the species diversity and species size of cladocera.

Venkataraman (1995) reported on the cladocera males of Indian region. The Cladoceran samples were collected in Tamilnadu, Rajasthan, Andaman and Nicobar Islands and West Bengal from various types of habitat such as rice fields, marshes, ponds, lakes, reservoir, streams, and rivers. A total of 16 species of freshwater Cladoceran male were reported in the study. In tropical and subtropical latitudes of India, males appear for a very short period and in small numbers. The adult males were not found to be similar to adult females, however, juveniles of males were found to have some similarity.

Zehra and Altaff (2002) redescribed the cyclopoid copepod Mesocyclops aspericornis from an Indian pond. The body of the species was transparent, cylindrical, elongated and distinctly segmented into four prosomal and five urosomal somites, whereas the body of the male was divided into four prosomal and six urosomal somites. The features such as antennae, antennule, legs 1 to 6 (P1 to P6) and also some of the species-specific characters of this organism had been described.

Sampaio et al studied the species composition and abundance of zooplankton community of 7 reservoirs of Paranapanema river, Brazil. Plankton samples were collected from the limnetic region of all reservoirs in each season. Diversity was evaluated using Shannon-Weiner index and Sorensen index. From 27 analysed samples in 7 reservoirs, a total of 76 species of rotifers, 2 species of calanoid copepods, 5 species of cyclopoid copepod and 26 species of cladocerans were recorded. The values for the Shannon-Weiner index varied from 1.5 to3.0 among the reservoirs. The Sorensen index showed that the similarity among the reservoirs was low. A positive relationship between the trophic state of reservoir and diversity of zooplankton community was recorded. Among the reservoirs surveyed, the oldest reservoirs had the highest species diversity and hence indicated a stable environment.

Gyllstrom and Hansson (2004) studied the induction, termination and importance of benthic pelagic coupling in the dormancy of zooplankton. The induction of dormancy was almost exclusively seasonal, which were dependant on temperature, photoperiod, food quality and quantity and other abiotic factors. The general factors were found to influence zooplankton growth, reproduction and mortality were water level, salinity, pH, nutrients, photoperiod and temperature, interspecific and intraspecific competition, invertebrate predation, vertebrate predation, and food quality and quantity.

The effect of temperature and viscosity on the ingestion rates of Daphnia galeata and Chydorus sphaericus was investigated with H 3 labelled Scenedesmus quadricaudas by Loiterton et al., (2004). Both Daphnia galeata and Chydorus sphaericus were cultured in the laboratory and the temperature and viscosity were changed and the ingestion rates monitored. The ingestion rates of Daphnia galeata was observed to be decreased to 50% and 80% at low temperature (100C) and increased viscosity respectively.

Whitman et al., (2004) characterized the lake Michigan coastal lakes using zooplankton assemblages. Zooplankton assemblages and water quality were examined in 11 northeastern lake Michigan coastal lakes of similar origin but varied trophic structure and limnological condition. Zooplankton samples were collected by vertical tows from 1 m from the lake bottom to the surface using a Wisconsin net. A total of 85 taxa were identified from 11 study lakes. The Shannon diversity index (loge) based on the lakes averages ranged from 2.07 to 2.29. Strong correlations were observed between differences in lake trophic status and zooplankton community. The rotifers were found to be the best indicators of trophic status when compared to the other groups.

Pandey and Verma (2004) studied the influence of catchment on chemical and biological characteristics of Baghdara lake and Udai Sagar lake in Southern Rajasthan. The two lakes were of constrasting features with Baghdara lake receiving runoff from undisturbed woodlands ad Udai Sagar lake receiving runoff from urbanized regions. The physicochemical and biological analysis of both the lakes reveals that Udai Sagar lake was polluted and reaching eutrophic condition, whereas Baghdara lake was unpolluted. The study also shows that the dredging of sediment containing phosphorus as a restoration measure for eutrophic lakes was effective.