Comparative Study of Present and Past Cladoceran Diversity in Manasbal Lake of Kashmir (India)

Abstract

Abstract:Present research was carried out to study the diversity of Cladocera in Manasbal Lake and compare it with previous studies. In present study, 21 species of cladocerans were recorded belonging to 5 families: Chydoridae, Daphnidae, Bosminidae, Macrothricidae and Sididae. Chydorids were responsible for major cladoceran diversity followed by daphnids. The frequently species found were Chydorus sphaericus, Graptoleberis testudinaria, Daphnia pulex, Ceriodaphnia reticulata and Bosmina longirostris. While comparing the cladoceran diversity of present study with earlier studies, many species present earlier were not found in present study due to increasing pollution of the lake. However, five species (Chydorus sphaericus, Graptoleberis testudinaria, Bosmina longirostris, Sida crystallina and Diaphanosoma brachyurum) recorded earlier were still present and were reported by all authors. This depicted that these species can tolerate wide range of fluctuations in environmental changes. Further, Daphnia pulex was not recorded in earlier studies but was recorded latter which also showed increased pollution in the lake as this species prefers polluted waters. Environmental changes have great influence on distribution of cladocerans and therefore, they act as excellent indicators of pollution. respectively, rest of the sites (SI to SIV) were sampled from the surface only (Figure 1). Keywords Water analysisThe sampling was carried out on monthly basis for a period of one year (September 2014 to August 2015). Water samples were analyzed in accordance with Welch (1948), Golterman and Clymo (1969), Golterman et al. (1978), Mackereth et al. (1978), Adoni et al. (1985) and American Public Health Association (2005). Biological analysisQualitative study of the Cladocera was carried out by hauling a standard plankton net (60 meshes/cm) at selected sites so as to cover maximum area (Tait et al., 1984). A plankton tube was attached to the lower end of the conical net and the material collected during hauling was preserved by adding 4% formalin at the collection site. Qualitative studies were carried out up to the genus/species level using the standard keys given by Pennak (1978); Edmondson (1992) and Battish (1992). For the quantitative studies Ruttner's sampler was used. Ten litres of water from each site, procured by the sampler, were sieved through the plankton net. One ml of sample was placed on Sedgewick Rafter Counting Cell of 1 ml capacity and studied under compound microscope for quantitative enumeration. For accuracy the counting was done in triplicate and average of three counts was used to calculate the population dynamics of various species and hence of total zooplankton in individuals per litre of water by the formula given by Welch (1948).Where, n=number of individuals per litre of water.a=average number of individuals in 1 ml of the concentrated sample.c=volume of the concentrated sample. l=volume of the original water sample sieved (10 litres). Results and DiscussionThe different physico-chemical parameters of w...