Hazra, AK; Gurupada, M; Dhrubajyoti, P
Present studies contain results of an ecological study involving the impact of different factors and some heavy metal pollutants on subterranean collembolan population and association with the soil microbes (Fungi and bacteria actinomycetes population) in reclaimed wetland embankment of Kolkata, West Bengal. Soil factors like temperature, moisture, pH, organic carbon, nitrate and phosphate and heavy metals such as mercury, copper, lead and zinc were taken into consideration. Fungi and bacteria-actinomycetes population and their interactions with these parameters and soil fauna were also studied. All these were found to vary seasonally. A total of 270 soil samples were drawn from various plots at monthly intervals in a period of thirty months (January 2003 to June 2005). Population density of total Collembola, fungi and bacteria-actinomycetes in order of abundance were 60.50%, 31.8% and 47.38% respectively at this site. The collembolan fauna encountered, belonged to 17 species under 16 genera of the families Hypogastruidae Isotomidae, Entomobryidae and Sminthuridae. Fungal population studied belonged to 8 genera and the bacterial-actinomycetes community comprised of 10 genera. Numerically the genus Lepidocyrtus occupied topmost position among all the collembolans and was widely distributed, Xenylla and Cyphoderus respectively occupied second and third position, and the other genera like Isotomurus, Homidia, Salina, Cryptopygus, Yosiia, Sminthurides, Seira, Isotomiella mentioned in order of dominance. Populations of most of the other genera were numerically low and irregular in distribution pattern. In order of dominance the Penicillium and the Bacillus occupied topmost position among the fungal and bacteria-actinomycetes communities respectively. The peak population of Collembola and fungi found to be coincided during March. However, the bacterial population peak varied from one year to another year of observation, which was found to be coincided with the collembolan/fungal population in this study site. The correlation between the populations of Collembola, fungi with that of bacteria-actinomycetes were positively significantly correlated this study site. Of the soil factors viz. moisture, organic carbon, nitrate and phosphate also showed positive significant correlation with Collembola, fungi and bacteria-actinomycetes population. The heavy metals like mercury, lead and zinc exhibited negative correlation with the total population of Collembola as well as fungi/bacteria-actinomycetes populations. The measure of association broadly indicates more significant values in the- complex biotic communities in soil (viz. between pairs of different genera/species of Collembola/fungi/bacteria-actinomycetes) at study site. From the present investigation it might be inferred that the effect of mechanical disturbances due to poor soil environment and dumping of municipal wastes (household refuses/industrial discharges) on soil surface which cause soil environment polluted and results to the reduction of the soil micro fauna/flora quantitatively or qualitatively. Thus, the reduction of these active biological agents the process of soil formation would become slow with the ultimate effects on soil health in general.
copper; heavy metals; lead; mercury compounds; microbial ecology; microbial flora; nitrate; phosphate; polluted soils; population density; reclaimed land; soil bacteria; soil fauna; soil flora; soil fungi; soil organic matter; soil pollution; soil types; wetland soils; wetlands; zinc; India; West Bengal; Bacillus; Collembola; Cryptopygus; Entomobryidae; Hypogastruridae; Isotomidae; Penicillium; Sminthuridae; Bacillaceae; Firmicutes; bacteria; prokaryotes; Hexapoda; arthropods; invertebrates; animals; eukaryotes; South Asia; Asia; Developing Countries; Commonwealth of Nations; Deuteromycotina; Eumycota; fungi; Cyphoderus; Homidia; Hyphomycetes; Isotomiella; Lepidocyrtus; microflora; organic matter in soil; Salina; Seira; Sminthurides; Xenylla; Yosiia; Soil Biology (JJ100); Pollution and Degradation (PP600); Industrial Wastes and Effluents (XX400); Animal Ecology (ZZ332); Microbial Ecology (ZZ333) (New March 2000)