Shifts in microbial communities, microbial biomass and organic matter mineralization for three mediterranean soils contaminated by metals

摘要

Microbial communities (phospholipid fatty acid pattern, bacterial growing strategies, eco-physiological index (EPI) and total bacteria counts, as a number of heterotorphic culturable bacteria), substrate-induced respiration (SIR), and nitrogen mineralization were studied in three Mediterranean soils at three different depth levels (A, B and C). Soils were experimentally treated with a final concentration of 1000 ppm of trace metals (Cu~(2+), Zn~(2+), Al~(3+), Fe~(2+), Pb~(2+), Ni~(2+), Mn~(2+), Cr~(3+) and Cd~(2+)). Solids were stored in 571 plastic containers for one year, and watered with 1001 during this period. Leachate was recovered through a bottom tap. Samples of the three depths were studied. Soil microbial communities showed different effects to other studies presented in the literature, but carrie out on non-Mediterranean soils. Dramatic differences were found between treated soils and untreated ones, but not between soils or horizons. The treated soil displayed a decrease in CFUs, SIR N-mineralization and EPI together with a dominance of r-growing strategists. The relative moles percent of several PLFAs, especially 15 : 0, 16:1#omega#7, cy17:0, and 18:1#omega#7 decreased because of the pollution of soils, whereas 10Me16, 18:2#omega#6, cy19:0, i16:0 and br17:0 showed higher values than in untrated soils.