Ref ID : 4584
Flemming Ekelund, Stefan Olsson, and Anders Johansen; Changes in the succession and diversity of protozoan and microbial populations in soil spiked with a range of copper concentrations. Soil Biol.Biochem. 35:1507-1516, 2003
Reprint
In File
Notes
We studied microbial and protozoan activity, diversity and abundance as affected by Cu2+ amendments ranging from 0 to 1000 µg g-1 over a 70-days period. At the end of the experiment the microbial population size, as indicated by substrate-induced respiration, had normalized for all Cu2+ concentrations, but 1000 µg g-1. Protozoan abundance was negatively affected by Cu2+, although, only in the first few weeks. A more detailed analysis of the individual components that make up the microbial and micro-faunal populations (phospholipid fatty acid (PLFA) profile and protozoan morphotypes), however, yielded a somewhat more complex picture. For the three highest Cu2+ amendments (160, 400 and 1000 µg g-1), there still was a significant reduction in number of differentiable protozoan morphotypes. The bacterial PLFA pattern suggested a shift from Gram-negative towards Gram-positive bacteria for the high amendments, a process where protozoan grazing most likely played a significant role. The ratio of the trans/cis isomers of the 16:1w7 fatty acid indicated at Cu2+, even at low and medium concentrations, induced physiological changes in the microbial population. The relatively slight changes in total microbial and micro-faunal abundance and activity, also at the highest Cu2+ concentrations, probably reflected that ability of the community to compensate for loss of taxa by functional substitution.