Will trees get enough nitrogen to sustain productivity in elevated CO2? The project proposes to explore how tissue nitrogen declines in future elevated carbon dioxide (eCO2) by studying the availability of soil nitrogen to plants and use of nitrogen by Eucalyptus woodland trees. Plant canopy nitrogen concentrations decline in nearly every large-scale eCO2 study done on native soils. The project plans to explore how changes in ecosystem nitrogen balance occur, by investigating if leaf nitrogen de ....Will trees get enough nitrogen to sustain productivity in elevated CO2? The project proposes to explore how tissue nitrogen declines in future elevated carbon dioxide (eCO2) by studying the availability of soil nitrogen to plants and use of nitrogen by Eucalyptus woodland trees. Plant canopy nitrogen concentrations decline in nearly every large-scale eCO2 study done on native soils. The project plans to explore how changes in ecosystem nitrogen balance occur, by investigating if leaf nitrogen declines under eCO2 due to the balance of plant activity versus changes in soil nitrogen availability. The outcomes are central to knowing the extent to which extra nitrogen ‘feeds’ the eCO2 fertilisation response and sustains long-term increases in productivity. Expected outcomes may support the development of management options to sustain future forest productivity.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.
To grow or to store: Do plants hedge their bets? This project aims to resolve a long-standing question about the function of perennial plants: how much of the carbon taken up by photosynthesis is used immediately for growth, and how much is kept in reserve as insurance against future stress? This question is important to our understanding of how plants respond to stresses such as severe drought, and yet lack of data and theoretical modelling currently hampers our ability to answer it. By applyin ....To grow or to store: Do plants hedge their bets? This project aims to resolve a long-standing question about the function of perennial plants: how much of the carbon taken up by photosynthesis is used immediately for growth, and how much is kept in reserve as insurance against future stress? This question is important to our understanding of how plants respond to stresses such as severe drought, and yet lack of data and theoretical modelling currently hampers our ability to answer it. By applying novel data analysis and modelling tools to recent experimental results, the project plans to test hypotheses for how plants allocate carbon between growth and storage in response to stress. Insights from the project may underpin better management of Australia’s vulnerable ecosystems.Read moreRead less
Promoting resilience of ecosystems through connectivity. The resilience of ecosystems in the face of major environmental disturbances is emerging as a major concern for modern ecology. Connectivity of ecosystem components is a critically important element of ecosystem function and should, theoretically, be central to system resilience. The relationship between connectivity and resilience, however, remains poorly substantiated by empirical data. By manipulating connectivity in laboratory experime ....Promoting resilience of ecosystems through connectivity. The resilience of ecosystems in the face of major environmental disturbances is emerging as a major concern for modern ecology. Connectivity of ecosystem components is a critically important element of ecosystem function and should, theoretically, be central to system resilience. The relationship between connectivity and resilience, however, remains poorly substantiated by empirical data. By manipulating connectivity in laboratory experiments using a well-understood model marine system, the project aims to determine how connectivity affects resilience. It could provide a crucial step towards integrating connectivity into management and conservation of natural resources.Read moreRead less
Predicting the consequences of drought-induced mortality for tree species in a changing climate. Tree mortality will be a dramatic manifestation of climate change as drought intensifies. A pre-existing record of mortality after recent drought in Eucalyptus woodland defines the moisture sensitivity of tree species and will be related to their functional traits, population dynamics and geography. This analysis will search for generalised characters that define the species that will be most suscept ....Predicting the consequences of drought-induced mortality for tree species in a changing climate. Tree mortality will be a dramatic manifestation of climate change as drought intensifies. A pre-existing record of mortality after recent drought in Eucalyptus woodland defines the moisture sensitivity of tree species and will be related to their functional traits, population dynamics and geography. This analysis will search for generalised characters that define the species that will be most susceptible to drought and will identify how future exaggerated drought will reorganise forest communities. The findings will contribute to understanding the vulnerability and resilience of our natural ecosystems with a changing climate.Read moreRead less
Linking phytoplankton to fisheries using zooplankton size spectra. This project aims to develop innovative numerical methods to understand the dynamics, carbon export, and trophic structure of zooplankton. The trophic links between phytoplankton, zooplankton and fisheries are unknown. The size- frequency distribution of zooplankton (size spectrum) is an innovative method for estimating their growth, predation and production as food for fish. Analysis of a global synthesis of zooplankton size dis ....Linking phytoplankton to fisheries using zooplankton size spectra. This project aims to develop innovative numerical methods to understand the dynamics, carbon export, and trophic structure of zooplankton. The trophic links between phytoplankton, zooplankton and fisheries are unknown. The size- frequency distribution of zooplankton (size spectrum) is an innovative method for estimating their growth, predation and production as food for fish. Analysis of a global synthesis of zooplankton size distributions from tropical to polar environments are expected to reveal these vital rates of pelagic ecosystems. The zooplankton rates will reveal, for the first time, the link between phytoplankton and fisheries, and will significantly improve ecosystem models and global assessments of environmental change.Read moreRead less
Methane uptake of forest soils. This project will provide a detailed understanding of capacity of soils in Australia to sequester the greenhouse gas methane. It will identify the main factors and processes controlling methane uptake in soils and improve predictive models will allow us to predict methane uptake in the future.
Dissolution of CaCO3 in sediments in an acidifying ocean. Dissolution of calcium carbonate (CaCO3) in sediments in the context of ocean acidification is poorly understood. This project will use in situ advective benthic chamber incubations and experimental manipulations under future ocean acidification scenarios to determine the controls on the dissolution of CaCO3 in sediments. This project is significant because changes in the dissolution of CaCO3 in sediments in an acidifying ocean are at lea ....Dissolution of CaCO3 in sediments in an acidifying ocean. Dissolution of calcium carbonate (CaCO3) in sediments in the context of ocean acidification is poorly understood. This project will use in situ advective benthic chamber incubations and experimental manipulations under future ocean acidification scenarios to determine the controls on the dissolution of CaCO3 in sediments. This project is significant because changes in the dissolution of CaCO3 in sediments in an acidifying ocean are at least as important, and potentially more important, than calcification to the future accretion and survival of carbonate ecosystems. It is expected that outcomes of this project will significantly advance our understanding of the drivers of the dissolution of CaCO3 in sediments and the functioning of globally important carbonate ecosystems.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
Hydraulic control on water use, growth and survival in tropical rainforest. This project aims to measure drought-related limits to water transport in the woody xylem tissue of trees in Australian tropical rainforests, to understand how this influences tree water use, photosynthesis, health and mortality risk. Tropical rainforests are sensitive to climate variability, especially drought, but this sensitivity is poorly understood, despite large effects regionally and globally. This project will co ....Hydraulic control on water use, growth and survival in tropical rainforest. This project aims to measure drought-related limits to water transport in the woody xylem tissue of trees in Australian tropical rainforests, to understand how this influences tree water use, photosynthesis, health and mortality risk. Tropical rainforests are sensitive to climate variability, especially drought, but this sensitivity is poorly understood, despite large effects regionally and globally. This project will compare forests that contrast strongly in seasonal drought stress, and use the information to develop a model designed for species-diverse forest, with subsequent potential global application. The understanding gained will enable widely applicable advances designed to feed through rapidly to regional- and global-scale models that inform land use, economic and social policy-making.Read moreRead less