Hatha, A A M; Krishna, M P; Rinoy, Varghese(Indian Society for Education and Environment, March , 2012)
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Abstract:
Soil microorganisms play a main part in organic matter decomposition and are consequently necessary to soil ecosystem
processes maintaining primary productivity of plants. In light of current concerns about the impact of cultivation and climate
change on biodiversity and ecosystem performance, it is vital to expand a complete understanding of the microbial community
ecology in our soils. In the present study we measured the depth wise profile of microbial load in relation with important soil
physicochemical characteristics (soil temperature, soil pH, moisture content, organic carbon and available NPK) of the soil
samples collected from Mahatma Gandhi University Campus, Kottayam (midland region of Kerala). Soil cores (30 cm deep)
were taken and the cores were separated into three 10-cm depths to examine depth wise distribution. In the present study,
bacterial load ranged from 141×105 to 271×105 CFU/g (10cm depth), from 80×105 to 131×105 CFU/g (20cm depth) and from
260×104 to 47×105 CFU/g (30cm depth). Fungal load varies from 124×103 to 27×104 CFU/g, from 61×103 to110×103 CFU/g
and from 16×103 to 49×103 CFU/g at 10, 20 and 30 cm respectively. Actinomycetes count ranged from 129×103 to 60×104
CFU/g (10cm), from 70×103 to 31×104 CFU/g (20cm) and from 14×103 to 66×103 CFU/g (30cm). The study revealed that there
was a significant difference in the depthwise distribution of microbial load and soil physico-chemical properties. Bacterial,
fungal and actinomycetes load showed a decreasing trend with increasing depth at all the sites. Except pH all other
physicochemical properties showed decreasing trend with increasing depth. The vertical profile of total microbial load was well
matched with the depthwise profiles of soil nutrients and organic carbon that is microbial load was highest at the soil surface
where organics and nutrients were highest
Description:
Indian J. Edu. Inf. Manage., Vol. 1, No. 3 (Mar 2012)
Hatha, A A M; Krishna, M P; Rinoy, Varghese(Indian Society for Education and Environment, March , 2012)
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Abstract:
Industrialization of our society has led to an increased production and discharge of both xenobiotic and natural chemical
substances. Many of these chemicals will end up in the soil. Pollution of soils with heavy metals is becoming one of the most
severe ecological and human health hazards. Elevated levels of heavy metals decrease soil microbial activity and bacteria need
to develop different mechanisms to confer resistances to these heavy metals. Bacteria develop heavy-metal resistance mostly
for their survivals, especially a significant portion of the resistant phenomena was found in the environmental strains.
Therefore, in the present work, we check the multiple metal tolerance patterns of bacterial strains isolated from the soils of MG
University campus, Kottayam. A total of 46 bacterial strains were isolated from different locations of the campus and tested for
their resistant to 5 common metals in use (lead, zinc, copper, cadmium and nickel) by agar dilution method. The results of the
present work revealed that there was a spatial variation of bacterial metal resistance in the soils of MG University campus, this
may be due to the difference in metal contamination in different sampling location. All of the isolates showed resistance to one
or more heavy metals selected. Tolerance to lead was relatively high followed by zinc, nickel, copper and cadmium. About
33% of the isolates showed very high tolerance (>4000μg/ml) to lead. Tolerance to cadmium (65%) was rather low (<100
μg/ml). Resistance to zinc was in between 100μg/ml - 1000μg/ml and the majority of them shows resistance in between
200μg/ml - 500μg/ml. Nickel resistance was in between 100μg/ml - 1000μg/ml and a good number of them shows resistance in
between 300μg/ml - 400μg/ml. Resistance to copper was in between <100μg/ml - 500μg/ml and most of them showed
resistance in between 300μg/ml - 400μg/ml. From the results of this study, it was concluded that heavy metal-resistant bacteria
are widely distributed in the soils of MG university campus and the tolerance of heavy metals varied among bacteria and
between locations
Description:
Indian J. Innovations Dev., Vol. 1, No. 3 (Mar 2012)