The effect of long-term mercury pollution on the soil microbial community

• Published in: FEMS microbiology ecology Vol. 36; no. 1; pp. 11 - 19
• Main Authors: Müller, Anne Kirstine, Westergaard, Kamma, Christensen, Søren, Sørensen, Søren Johannes
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01-06-2001; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Biochemistry and biology; Biological and medical sciences; carbon; Chemical, physicochemical, biochemical and biological properties; chitinase; chronic exposure; Colony morphology; community structure; denaturing gradient gel electrophoresis; DGGE; Diversity; Ecoplates; Fundamental and applied biological sciences. Psychology; Heavy metal; long term effects; mercury; Mercury pollution; microbial biomass; Microbial community; Microbial ecology; Microbiology; nucleotide sequences; Physics, chemistry, biochemistry and biology of agricultural and forest soils; polluted soils; Protozoa; ribosomal DNA; Soil; soil microorganisms; soil pollution; Soil science; Various environments (extraatmospheric space, air, water); Colony morphology; Mercury pollution; Ecoplates; Diversity; Soil; Microbial community; DGGE; Heavy metal; Soils; Pollution
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1016/S0168-6496(01)00112-X

The effect of long-term exposure to mercury on the soil microbial community was investigated in soil from three different sites along a pollution gradient. The amount of total and bioavailable mercury was negatively correlated to the distance from the center of contamination. The size of the bacterial and protozoan populations was reduced in the most contaminated soil, whereas there was no significant difference in fungal biomass measured as chitinase activity. Based on the number of colony morphotypes, moreover, the culturable bacterial population was structurally less diverse and contained a higher proportion of resistant and fast-growing forms. The profiles of amplified 16S rDNA sequences obtained from community DNA by denaturating gradient gel electrophoresis (DGGE) also reflected the altered community structure and decreased diversity along the mercury gradient as expressed in terms of the number and abundance of bands. The functional potential of the microbial population measured as sole carbon source utilization by Ecoplates
® differed between the soils, but there was no change in the number of substrates utilized. The observed changes in the different soil microbial populations are probably a combination of both direct and indirect effects of the mercury contamination.