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
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
Oxygen isotope discrimination during C4 photosynthesis. Plants with the C4 photosynthetic pathway, like sugarcane and pasture grasses, are vital to Australian agriculture and natural ecosystems. This project will use novel laser spectroscopy to measure oxygen isotope discrimination during photosynthesis and quantify the influence of C4 plants on isotopic signatures of atmospheric CO2.
Disentangling climate and evolutionary controls over the temperature dependence of leaf respiration. The project will use field and laboratory studies to establish if there are systematic differences in the temperature responses of leaf respiration in plants adapted to hot and cold environments. The results will enable climate modellers to better predict impacts of climate change on carbon exchange between vegetation and the atmosphere.
A step change in modeling leaf respiration-photosynthesis relationships . This project aims to use innovative, high-throughput technologies to develop a novel framework that links daytime photosynthesis and starch/amino acid mobilisation to variations in night-time leaf respiration. Variations in leaf respiration can have large impacts on ecosystem functioning and the Earth’s climate. Although advances have been made in respiration modelling, current models are unable to predict dynamic, day-to- ....A step change in modeling leaf respiration-photosynthesis relationships . This project aims to use innovative, high-throughput technologies to develop a novel framework that links daytime photosynthesis and starch/amino acid mobilisation to variations in night-time leaf respiration. Variations in leaf respiration can have large impacts on ecosystem functioning and the Earth’s climate. Although advances have been made in respiration modelling, current models are unable to predict dynamic, day-to-day variations in respiratory rates. Expected outcomes include equations that predict daily variations in night-time leaf respiration for environments across Australia and overseas. Benefits to planners include the ability to more accurately model vegetation-atmosphere carbon exchange and future changes in climate. Read moreRead less
The causes and effects of mortality in tropical Australian trees. Drought can cause the widespread death of tropical trees resulting in large emissions of carbon dioxide to the atmosphere, but predictions of tree death during drought remain rudimentary. This project will combine new data and modelling on how Australian tropical trees respond to drought to improve estimates of tree mortality risk and its impacts.
Using Arabidopsis mutants to discover the role of guard cell chloroplasts in the stomatal response to light. This project will use novel molecular approaches to study how guard cells on the surface of leaves regulate plant water loss and CO2 uptake. This will provide new molecular tools for improving plant water use in agricultural species and aid process based modelling of CO2 and water exchange needed for predicting climate change.
Metabolite pools and their implications for plant responses to global change. Australian landscape management faces significant challenges from existing land practices and the effects of climate change. Effective management and targeted remediation requires an understanding of the processes that drive ecosystem function. The development of broadly applicable tools for the monitoring of plant and ecosystem health is therefore of considerable interest. Flexibility in core processes of plant functi ....Metabolite pools and their implications for plant responses to global change. Australian landscape management faces significant challenges from existing land practices and the effects of climate change. Effective management and targeted remediation requires an understanding of the processes that drive ecosystem function. The development of broadly applicable tools for the monitoring of plant and ecosystem health is therefore of considerable interest. Flexibility in core processes of plant function represents a significant opportunity to develop such tools. With a focus on plant metabolites, this project will characterise how Australian trees alter the allocation of resources to cope with environmental changes and produce metabolite-based selective traits for stress tolerance in Australian trees. Read moreRead less
Effects of global climate change on marine phytoplankton: interactions between UV radiation and elevated atmospheric carbon dioxide levels. Global climate change is one of the most significant ecological challenges for the 21st Century. Phytoplankton contribute over 45% of the planet's annual net primary production and form the basis of most aquatic food chains. Conversely, some phytoplankton are toxic and cause problems in marine and fresh waters. Climate change can potentially disrupt aquatic ....Effects of global climate change on marine phytoplankton: interactions between UV radiation and elevated atmospheric carbon dioxide levels. Global climate change is one of the most significant ecological challenges for the 21st Century. Phytoplankton contribute over 45% of the planet's annual net primary production and form the basis of most aquatic food chains. Conversely, some phytoplankton are toxic and cause problems in marine and fresh waters. Climate change can potentially disrupt aquatic foodchains by its impact on primary production by phytoplankton or stimulating growth of potentially toxic forms. Our project will investigate the combined impact of increasing carbon dioxide and ultraviolet light on phytoplankton and thereby help climate modellers assess the impact of climate change on aquatic ecosystems and particularly on the nation's and the world's fisheries.Read moreRead less
Eucalypt growth in past and future environments - a novel approach to understanding the impacts of atmospheric CO2 and climate. The impact of climate change and rising atmospheric CO2 on Australia's plantation and native forests is a major concern for government and land managers. These forests are important for environmental, aesthetic, and economic purposes, including carbon sequestration and trading. Forests use large amounts of water, reducing stream flow and water supplies for rural and u ....Eucalypt growth in past and future environments - a novel approach to understanding the impacts of atmospheric CO2 and climate. The impact of climate change and rising atmospheric CO2 on Australia's plantation and native forests is a major concern for government and land managers. These forests are important for environmental, aesthetic, and economic purposes, including carbon sequestration and trading. Forests use large amounts of water, reducing stream flow and water supplies for rural and urban communities. Knowledge generated from the proposed project will provide insight into mechanisms driving productivity and water use of forests in current and future environments. The knowledge will be used by land managers and government to develop strategies to cope with future impacts of climate change.Read moreRead less