Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water c ....Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water cycles and reconstruct past climates. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for use by paleoclimatologists, plant scientists and to constrain global carbon cycles and develop accurate models of leaf water isotopes to reduce uncertainty in climate models.Read moreRead less
How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-gree ....How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-greens. This research aims to determine how the proteins that make up carboxysomes are 3-dimensionally arranged and how these structures function to enhance rates of CO2 fixation. A more thorough understanding of the carboxysome is likely to have potential applications in industrial nano-technology and improve our understanding of oceanic primary productivity.Read moreRead less
Carbon uptake and water use by plants: is there pre-stomatal control? Society relies on mathematical descriptions of climate change, weather forecasting, crop performance, and other processes in which the control of carbon uptake and water loss by plants forms a basic element. Scientists also use the same element in ascribing sources and sinks of carbon dioxide (CO2), describing vegetation, hydrological and ecological processes. A key physiological assumption in this element is now in doubt and ....Carbon uptake and water use by plants: is there pre-stomatal control? Society relies on mathematical descriptions of climate change, weather forecasting, crop performance, and other processes in which the control of carbon uptake and water loss by plants forms a basic element. Scientists also use the same element in ascribing sources and sinks of carbon dioxide (CO2), describing vegetation, hydrological and ecological processes. A key physiological assumption in this element is now in doubt and we will test it rigorously and if necessary provide a robust alternative. We will do this by developing a novel 'window' on intact leaf functioning that will reveal the concentration of water vapour and other gases inside leaves.Read moreRead less
Building resilient alpine environments with less snow. In this project, we aim to build resilience into alpine National Parks and Alpine Resorts to counter the effects of ongoing declines in snow. Alpine environments depend on snow to regulate water flows, insulate vegetation, control soil erosion and promote proper ecosystem functioning. How these processes will operate in a snow-free future is unknown. We will determine how and where snow characteristics drive soil water availability for plant ....Building resilient alpine environments with less snow. In this project, we aim to build resilience into alpine National Parks and Alpine Resorts to counter the effects of ongoing declines in snow. Alpine environments depend on snow to regulate water flows, insulate vegetation, control soil erosion and promote proper ecosystem functioning. How these processes will operate in a snow-free future is unknown. We will determine how and where snow characteristics drive soil water availability for plants and which plant species have the best adaptation and regeneration potential under extreme conditions such as heat, frost and drought. Benefits of the project include innovative land management and rehabilitation solutions, to safeguard Australia's alpine areas under changing environmental conditions.Read moreRead less
Understanding the mechanisms of thermal acclimation in the symbiotic algae (Symbiodinium) within cnidarian corals. Global warming is a major threat to coral reefs, contributing to devastating coral bleaching. This project will provide new insight into how coral reefs can respond to rising global temperature through clarifying the thermal acclimation mechanisms in corals using molecular techniques.
What limits CO2 diffusion inside leaves? Dissecting the diffusion path with Arabidopsis mutants. Human induced increase in atmospheric carbon dioxide is now generally accepted as contributing to global warming. Forecasting our future impact relies on models of terrestrial photosynthesis which use a signature in the atmosphere created by plants when they discriminate against the heavy stable isotope of carbon during photosynthesis. Discrimination between isotopes is affected by carbon dioxide dif ....What limits CO2 diffusion inside leaves? Dissecting the diffusion path with Arabidopsis mutants. Human induced increase in atmospheric carbon dioxide is now generally accepted as contributing to global warming. Forecasting our future impact relies on models of terrestrial photosynthesis which use a signature in the atmosphere created by plants when they discriminate against the heavy stable isotope of carbon during photosynthesis. Discrimination between isotopes is affected by carbon dioxide diffusion within leaves and key steps in this process will be identified through the use of Arabidopsis mutants. Better representation of this process in models will improve estimates of terrestrial photosynthesis and climate change forecastsRead moreRead less
Unsaturation of vapour pressure inside leaves: fundamental, but unknown. This project aims to determine when and to what extent the air inside leaves becomes unsaturated with water vapour. All current interpretation and modelling of leaf gas exchange assumes saturation under all circumstances. Compelling evidence has been obtained that suggests this is not true under moderate air vapour pressure deficits. A novel technique will be employed to assess the water vapour concentration of the air insi ....Unsaturation of vapour pressure inside leaves: fundamental, but unknown. This project aims to determine when and to what extent the air inside leaves becomes unsaturated with water vapour. All current interpretation and modelling of leaf gas exchange assumes saturation under all circumstances. Compelling evidence has been obtained that suggests this is not true under moderate air vapour pressure deficits. A novel technique will be employed to assess the water vapour concentration of the air inside leaves based on stable isotope analysis of carbon dioxide and water vapour exchanged between leaves and air. The project is expected to provide fundamental knowledge about how stomata regulate photosynthesis and water use, with significant implications for modelling vegetation function and for improving the performance of crop plants.Read moreRead less
Will stomatal responses to humidity and carbon dioxide constrain tropical forest productivity as atmospheric carbon dioxide rises? This project will investigate two physiological processes that will partly determine growth responses of tropical forest trees to rising atmospheric carbon dioxide. The project will produce equations summarising physiological responses that can be incorporated into process-based models of tropical forest productivity.
Reading the isotopic archive: carbon and oxygen stable isotope ratios as recorders of plant physiological processes. This project will investigate how plant physiological processes are reflected in stable isotope ratios of carbon and oxygen in plant tissues. Results will contribute towards a mechanistic understanding of the processes that cause isotopic modifications, thereby enabling an improved interpretation of naturally occurring stable isotope signals.
Testing climatic, physiological and hydrological assumptions underpinning water yield from montane forests. Water collected in dams and reservoirs remains the mainstay water resource for Australian cities, towns and industry. Overwhelmingly, that water is collected from forested catchments where the water balance of forest stands is dominated by the amount of water used by trees. Characterising tree water use, its response to changing climatic and nocturnal conditions, and other aspects of sta ....Testing climatic, physiological and hydrological assumptions underpinning water yield from montane forests. Water collected in dams and reservoirs remains the mainstay water resource for Australian cities, towns and industry. Overwhelmingly, that water is collected from forested catchments where the water balance of forest stands is dominated by the amount of water used by trees. Characterising tree water use, its response to changing climatic and nocturnal conditions, and other aspects of stand hydrology, are crucial to our ability to predict and model future water yields. Working in the Cotter catchment near Canberra and the upper Kiewa catchment in north-east Victoria, we aim to help the agencies responsible for water and catchment management to improve the security of their forecasts of water yield and their on-ground management. Read moreRead less