|
| Applying signature lipid biomarker (SLB) techniques toward the assessment of below ground microbial processes in the rhizosphere and bulk soil has provided added insight into the effects of elevated CO2 levels and soil disturbance on microbial populations. This research focused on the analysis of ester-linked polar lipid fatty acids (PLFA) to ascertain both microbial and eukaryotic biomass, community structure and nutritional/physiological status from rhizosphere and soil samples obtained from a number of collaborators. The signature biomarker technique allows the researcher to examine the microbial community in-situ without the necessity of culturing recoverable isolates, which have been shown to represent less than 1% of the population in soils. In terms of rhizosphere microbial populations, our research has shown there was a linear increase in microbial biomass associated with the increase in the fine root mass under elevated CO2. There was also a shift in the community structure of these rhizosphere populations favoring actinomycete type bacteria. In bulk soils it was demonstrated that after disturbance event such as tillage or irrigation the microbial community structure that existed prior to the disturbance will be re-established. |
|
| |
 |
|
