Open AccessZinc contamination decreases the bacterial diversity of agricultural soil
Author(s) -
Moffett Bruce F.,
Nicholson Fiona A.,
Uwakwe Nnanna C.,
Chambers Brian J.,
Harris James A.,
Hill Tom C.J.
Publication year - 2003
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2003.tb01041.x
Subject(s) - biology , biosolids , soil water , sewage sludge , agronomy , contamination , soil test , sewage , zinc , species evenness , soil contamination , environmental chemistry , veterinary medicine , ecology , species diversity , environmental science , environmental engineering , chemistry , medicine , organic chemistry
Around half a million tonnes of biosolids (sewage sludge dry solids) are applied to agricultural land in the United Kingdom each year, and this may increase to 732 000 t by 2005/6. The heavy metals contained in biosolids may permanently degrade the microbial decomposer communities of agricultural soils. We used amplified ribosomal DNA restriction analysis of the extractable bacterial fraction to compare the diversity of a zinc‐contaminated soil (400 mg kg −1 Zn; pH 5.7 and 1.36% C org ) with that of a control soil (57 mg kg −1 Zn; pH 6.2 and 1.40% C org ) from a long‐term sewage sludge experiment established in 1982 at ADAS Gleadthorpe. Comparison of the restriction fragment length polymorphisms of 236 clones from each soil suggested that the stress caused by zinc toxicity had lowered bacterial diversity. There were 120 operational taxonomic units (OTUs) in the control soil, but only 90 in the treated soil, a decrease of 25%. While the control soil had 82 single‐occurrence OTUs the contaminated soil had only 52. The fall in diversity was accompanied by a decrease in evenness. The most abundant OTUs in the contaminated soil (which tended to be common to both soils) accounted for a higher proportion of clones than in the control. The most dominant OTU, in both soils, belonged to the Rubrobacter radiotolerans group of the high G+C Gram‐positive bacteria. The data was also used to develop efficient sampling strategies.