Microbial Consumption of Methanol in a Grassland
Soil Sciences
Final Report Abstract
Grasslands are substantial global sources of methanol, which is besides methane and isoprene the third most abundant and reactive volatile organic compound (VOC) in the troposphere. However, environmental physiology of soil microorganisms that impact on methanol flux in terrestrial ecosystems, i.e. its microbial methanol sink, has largely not been investigated. Previous work of the applicant suggests that hitherto unknown soil bacteria are involved in ambient methanol oxidation of soil. The project MethanolSINK addressed thus, methanol-utilizers in two typical plant species that occur frequently in temperate grasslands, i.e. the grass Festuca arundinaceae L. and the flower Taraxacum officinale L. It was the main goal to test if those plant species were associated with distinct soil and phyllosphere methanol utilizer communities by employing stable isotope probing (SIP) and a metagenome based approach. We identified such bacterial methanol utilizers and found mainly differnencs between the root and phyllosphere community. In a corroborative laboratory experiment the ratio of below-ground and above-ground methanol flux has been resolved. Radioactive tracer experiments with 14C-methanol localized similar high potential activities to consume methanol in both aboveground (leaves) and belowground plant organs, i.e. its root system. Thus, to understand methanol fluxes in grassland ecosystems also the rooted soil needs to be considered as substantial reactive compartment in grasslands. Our results also suggest that not only biomasss but also plant taxonomy may impact on this belowground microbial methanol sink. Originally over a vegetation period, methanol flux and transcribed gene markers of active methanol utilizers should have have been also assessed in a specific grassland. This goal could not be achieved due to time constraints provoked by the fact that scientific personell changed and the applicant moved from the original employer to a new one.
