Aerated soils such as those found in forests and woodlands can
be important sinks of the atmospheric greenhouse gas, methane
(CH4). The magnitude of CH4 fluxes at the
soil surface is determined by methanotrophs (oxidisers) and
methanogens (producers), and there are several factors that control
these microbial communities along with the transport of
CH4 through the soil substrate. For example, soil
moisture affects methane diffusion with consumption being shown to
decrease with increasing soil moisture. Inorganic nitrogen is also
an important controlling factor and has been shown to inhibit
CH4 oxidation as ammonium and nitrate compete with
methane for active sites on methane monooxygenase, an enzyme that
catalyses methane oxidation. Other soil properties that influence
CH4 uptake include pH, soil depth and soil particle
size. Fire can affect all of these soils properties which in
turn affect CH4 uptake.
The aim of this project is to investigate the activity of
methanotroph populations in response to varying a range of soil
properties and condition. This will provide a better understanding
and allow prediction of the effects that changing weather patterns
and fire will have on the uptake of methane in alpine ecosystems in
the Bogong High Plains. Molecular studies (T-RFLP) are also planned
to be used to characterise populations of methanotrophs and
methanogens from these soil systems.
