It is important to note that only dry copper surfaces are amazingly lethal to bacteria. The difference between dry and wet surfaces, such as copper pipes, is that only dry surfaces are inhospitable environments for bacterial growth. Bacteria can easily grow and reproduce in wet environments, and in so doing, they can develop resistance to copper. Resistance has not been observed to develop on dry copper surfaces.
(C. Esprito Santo, E.W. Lam, C.G. Elowsky, D. Quaranta, D.W. Domaille, C.J. Chang, and G. Grass, 2011. Bacterial killing by dry metallic copper surfaces. Appl. Environ. Microbiol. 77: 794-802.)
Organic Vs. Conventional Farming: No Clear Answers From Nitrogen Fixing Bacteria Counts
The population and diversity of nitrogen-fixing bacteria in agricultural soils varies more according to what crop was previously farmed than with whether those soils are organically or conventionally farmed, according to a paper in the February 2011 issue of the journal Applied and Environmental Microbiology.
This study was conducted as part of the ongoing and long-standing Nafferton Factorial Systems Comparison study in Northumberland in northeast England, UK. The Nafferton study has conventional and organic plots side by side, enabling precise comparisons between the two methods.
In the study, the researchers analyzed soil samples from both sets of plots, once each in March, in June, after application of fertilizer (manure to organic plots, chemical fertilizer to conventional), and in September, following application of pest control measures.
"In general, you would expect organic fertilizers and pesticides to be less harmful than conventional ones," says first author Caroline H. Orr of Northumbria University, Newcastle-upon-Tyne, UK. "However, w
|Contact: Jim Sliwa|
American Society for Microbiology