Soil Bacteria
Whilst much publicity is given to the many and varied species of organism indigenous to biomes such as the rainforests scant attention is paid to soil in gardens and fields much closer to home. However, such soils play host to an incredibly large and diverse population of bacteria. Whilst species of soil dwelling bacteria are known to number in the thousands we still know astonishingly little about them. This is due largely to the fact that only around, at best, 10% of soil bacteria are actually culturable in the laboratory environment. Hence, the majority of bacteria resident in soil are as yet uncharacterised.
One promising method aiding in the characterisation of these soil bacteria is the use of light stable isotopes. By labelling specific growth substrates, e.g. methane, bacteria with a specific functional role can be labelled isotopically. Once labelled, compounds derived from these bacteria may be extracted, isolated and analysed to reveal information about these hitherto unknown bacterial species; if the DNA is sufficiently labelled (to allow separation on a centrifugal gradient) then there is even the possibility of phylogenetic characterisation. Using such methods soil bacteria responsible for the oxidation of methane at atmospheric levels have already been detected and classified. This represents just a first step in what is promising to be an exciting and ever expanding area of research.
