Current projects
Brief details of projects are below. For additional info click on the links. Please contact us if you are interested in these projects
Life under the snow: how does snow depth affect ecosystem processes?
Australia's high country is characterised by huge spatial and temporal variation in snow depth. This project is investigating how variation in snow depth affects ecosystem cycling of carbon and nutrients.
How do plants cope with temporal variability in water and nutrients?
We have an ARC Discovery project to investigate the ecology and physiology of temporal variation in water and nutrient supply. The fundamental premise of this work is that plants must tolerate long periods of low water and nutrient availability and yet be able tro respond quickly to brief periods of high water and nutrient availability.
Economics of C, N and water use in Acacia and Eucalyptus
This study is examining adaptation of Acacia and Eucalyptus species to water and nutrient limitations. A series of field and glasshouse experiments are examining variation among and within species in growth rate, leaf morphology, leaf biochemistry (e.g. N allocation to Rubisco) and the economics of N and H2O use in photosynthesis.
Ecosystem cycles and plant uptake of N
A central assumption of ecosystem N cycling has been that organic nitrogen (N) must be converted to inorganic N (ammonium and nitrate) to be available for plant uptake, and thus N mineralization has been viewed as the bottleneck in plant N nutrition. We are investigating the new hypothesis that plants can bypass the mineralization bottleneck by taking up organic N.
High temperature limits of leaf function
This project is investigating the high-temperature tolerance of Acacia, Eucalyptus and Quercus species. We are examining how high temperature interacts with drought and high light intensities, and variation among species in the critical temperature that causes leaf death.
Limitation of photosynthesis by internal conductance
This project is examining the implications for leaf-level photosynthesis of the resistance to CO2 movement from sub-stomatal cavities to sites of carboxylation. This resistance involves CO2 crossing cell walls, plasma memebrane, cytosol and chorooplast envelope, and it is normally described mathematically as internal conductance. The effect of internal conductance on photosynthesis and water loss is being determined via a combination of literature reviews, direct measurements and modeling.
Past projects
The effect of ozone fumigation on photosynthesis of Fagus sylvatica
This project is examining: 1) variation in internal conductance and photosynthetic limitations between sun and shade leaves of Fagus sylvatica, and 2) whether free-air fumigation affects internal conductance and photosynthetic limitations. Measurements of photosynthesis (A, Vcmax), gs and gi are being used to apportion limitations to biochemical, internal and stomatal factors.
Response of cool-temperate rainforest species to sunflecks
We are examining the response of photosynthesis and stomatal conductance to sunflecks. Dynamic and chronic photoinhibition is being diagnosed from measurements of chlorophyll fluorescence and xanthophyll pigments. Our studies are focusing on species from cool-temperate rainforest dominated by Nothofagus cunninghamii.
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