Potential Honours or PhD Projects in Greenhouse Research and Ecophysiology
Potential PhD Projects
- Savanna ecosystems and climate change - APAI - PhD Scholarship
- Are termites important for climate change?
- Plant adaptations to environmental stresses - Drought Stress
- Plant adaptations to environmental stresses - Salt stress
- Carbon cycling in forest ecosystems
- Modelling of carbon sequestration and forest growth
- Nutrient cycling in forest ecosystems - Importance of nitrogen fixation in forest ecosystems
- Nutrient cycling in forest ecosystems - Soil microbial transformation of nitrogen
Potential Honours Projects
- Salinity tolerance of eucalypts – importance of apoplastic solutes
- Mechanisms of drought tolerance in eucalypts – active or passive osmotic adjustment
- Forest soils and greenhouse gas exchange – soil moisture, temperature and fertility
- Land-use change in Victoria and the greenhouse gas balance
Potential PhD/Masters Projects
APAI - PhD Scholarship - Savanna ecosystems and climate change
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Savanna ecosystem near Daly River, 200 km south of Darwin, NT |
Project Background: Savanna ecosystems account for 25% of Australia’s landmass, yet not much is known about their role in climate change. Soil derived emissions of nitrous oxide and methane, plus carbon sequestration, will be assessed at savanna sites of contrasting land use (cleared vs. uncleared, burnt vs. unburnt). Soil measurements will be made in conjunction with on-going measurements of carbon fluxes from vegetation and the project will provide a complete greenhouse gas (GHG) emissions estimate for these extensive tropical landscapes. This project will have three major research themes; 1) temporal variability of soil GHG fluxes in savanna ecosystems, 2) the effect of land-use change on GHG and 3) the effect of fire on soil fluxes. The project will utilise sophisticated field trace gas analysis system for periods of continuous measurement and the student will receiving training in a wide a range of field and laboratory analytical techniques, such as 15N and 13C stable isotope mass spectrometry and gas chromatography. The projects will focus on the Daly and Howard River catchments of the Northern Territory.
This project is part of a recently awarded ARC Linkage grant at the Charles Dawin University in Darwin, NT.
Scholarship: An Australian Postgraduate Award Industry (APAI) is available as part of the ARC Linkage Grant
Qualification: Relevant honours or postgraduate qualification (minimum H2A average) in environmental science, biology, chemistry, climatology, agricultural science or equivalent.
Contact: |
Stefan Arndt (sarndt@unimelb.edu.au) , Burnley Campus, ( 9250 6819) |
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Steve Livesley (sjlive@unimelb.edu.au), Burnley Campus, ( 9250 6818) |
Are termites important for climate change?
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Magnetic termites near Darwin |
Wood eating termites near Daly River |
Background: Termites can contribute significantly to climate change due to their ability to emit the greenhouse gases methane and carbon dioxide. Termites are also valuable because they influence the nitrogen dynamics of savanna ecosystems. There is little known about termites and greenhouse gas emissions in savanna ecosystems and their contribution to global warming and the only data thus far are from laboratory measurements. Investigating the role of termites in savanna greenhouse gas exchange will require ground-breaking research and dedication by a PhD student.
Project: This PhD project will investigate greenhouse gas emissions by termites in the Northern Territories using automated field gas chromatography and in the laboratory in Melbourne. The research is part of a recent ARC Linkage project with Charles Darwin University, Monash University and IMK/IFU in Germany. Field sites are located near Darwin and in Daly River, NT
| Contact: | Stefan Arndt (sarndt@unimelb.edu.au) , Burnley Campus, ( 9250 6819) |
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Steve Livesley (sjlive@unimelb.edu.au), Burnley Campus, ( 9250 6818) |
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Berhan Ahmed (b.ahmed@unimelb.edu.au) Parkville Campus, ( 8344 8084) |
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Nigel Stork (nstork@unimelb.edu.au) Burnley Campus ( 9250 6806) |
Plant adaptations to environmental stresses
Drought stress
The availability of water is one of the most dominant factors influencing the distribution of tree species in Australia . The physiological adaptation to arid environments by tree species can be achieved through drought avoidance (e.g. deep root systems) or drought tolerance. Drought tolerance can be combination of physiological (e.g. stomatal control of water loss), morphological (e.g. leaf thickness, sunken stomata) or biochemical (osmotic adjustment, drought insensitive enzymes) traits. The mechanisms that enable growth and survival of trees in arid environments are unknown for most eucalypt species. The understanding of those mechanisms is important for a sustainable management of forest ecosystems in light of climate change (e.g. increasing aridity) and species selection for re-forestation of cleared or marginal land.
Aim : Investigate the drought tolerance mechanisms of dryland eucalypt species
Experimental design : Controlled experiments in the glasshouse and field studies
Methods : Ecophysiological (water status and gas exchange) and biochemical methods (chemical analysis of plant solutes)
Salt stress
Salinity is one of the most prominent and important environmental problems influencing the Australian landscape. Plant species that can withstand increasing soil or groundwater salinity are therefore an important integral part of the re-vegetation and re-forestation of salinity affected landscapes. Research has focused on the selection of salt resistant tree species but the physiological mechanisms that enable growth in salt affected landscapes are still poorly understood. Tree species can either follow a salt avoiding strategy, i.e. avoiding the uptake of salt by selective root based ultrafiltration, or be salt tolerant. Salt tolerance has been described as maintaining a balance between allowing sufficient salt to enter the shoot for osmotic adjustment, and preventing the accumulation of toxic levels of salt within the plant. Both strategies will have consequences for re-vegetation of salt effected landscapes - one mechanism retaining salt in the soil and the other removing it. A process understanding of the salt resistance mechanisms of tree species is therefore a prerequisite before re-vegetation projects should be implemented.
Aim : Investigate the salt resistance mechanisms of dryland eucalypt species
Experimental design : Controlled experiments in the glasshouse and field studies
Methods : Ecophysiological (water status, gas exchange, osmometry) and biochemical methods (chemical analysis of plant solutes).
Carbon cycling in forest ecosystems
Climate change increases the need to understand the processes influencing the uptake and sequestration of carbon dioxide (CO2) in tree biomass.
Carbon cycling processes in forest ecosystems
The allocation of carbon in a forest plays a major role in the carbon cycle. Forests allocate substantial amounts of biomass belowground (root systems) and also into the soil. Forests also lose a lot of sequestered carbon via respiration - a mature forest can lose as much carbon through respiration as it fixes through photosynthesis. Carbon sequestration into forest soils, on the other hand, can be substantial.
The relative allocation of carbon in a forest ecosystem is currently unknown for most forest ecosystems. The investigation of the full carbon budget of a forest ecosystem provides the scientific basis for the calibration of process based forest growth models and a more accurate carbon accounting. If carbon allocation to roots or soils can be accurately predicted and is scientifically validated, it can be accounted for as carbon credits.
Aim : Investigation of parameters influencing carbon sequestration and carbon allocation in trees and forests (soils, climate, respiration)
Experimental design : Mainly field based investigations
Methods : Classical forest inventory methods and ecophysiological methods
Modelling of carbon sequestration and forest growth
There is an increasing need to develop tools that enable an accurate prediction of forest growth and carbon sequestration. These data have been developed and tested for plantation species but hardly any predictive models are available for native forest ecosystems. Recent initiatives by the Victorian Government invested in the establishment of biodiversity plantings, thereby creating new "native" forests on former agricultural land. No predictive tools are available that enable predictions on forest growth and carbon allocation of those plantings or native forests. Collaboration with the Department of Sustainability and Environments Forest Resource Inventory group enables access to a large database of forest growth measurements in native forest ecosystems in Victoria . This database provides the basis for model development and validation of forest growth and carbon sequestration models for native forest ecosystems in Victoria .
Aim : Develop predictive tools for forest growth and carbon sequestration in native forests in Victoria
Experimental design : Using data from forest growth databases to develop and validate predictive models
Methods : Computer simulation models, GIS
Nutrient cycling in forest ecosystems
Importance of nitrogen fixation in forest ecosystems
The abundance of N2 fixing acacias is one of the most prominent characteristics of Australia 's landscapes. There are more than 1000 acacia species in Australia and they occur in almost every forest ecosystem in Australia . The ancient and highly weathered status of Australian soils means that they are generally depleted of nutrients, and as such forest plant species have had to adapt to this situation. N2 fixing species, like acacias, are an integral component of Australian forests because they can provide an invaluable input of N to ecosystems re-establishing on already nutrient deprived soils, when recovering from large nutrient losses during and after fire disturbance. However, the contribution of N2 fixing species to the N balance of forest ecosystems in Australia is still poorly understood. The N added to forest ecosystems by N2 fixing species can ultimately be exploited by other forest species, but it can also be lost from the forest system through leaching or gaseous volatilization
Aim : Investigate the nitrogen cycle and importance of N2 fixing species in native and plantation forest ecosystems
Experimental design : Mainly field based research
Methods : Ecophysiological, chemical and stable isotope methods
Soil microbial transformation of nitrogen
A critical stage in the cycling of nitrogen in forest systems is performed by soil microbial communities (bacteria and fungi). Organic matter that enters the soil system through litterfall, root turnover or exudation is decomposed and mineralised, thereby converting organic N to plant available inorganic N once more. A sequence of mineralization processes performed by different microbial groups convert organic N to inorganic ammonium (NH4) and then inorganic nitrate (NO3 ). The quality of the organic litter inputs, the soil moisture and temperature determine the rate of these mineralization processes and these differ according to forest type, age and soil type. Soil inorganic N can be retained and continue cycling in the forest system through either plant uptake or microbial consumption, but can also be lost from the forest system through microbial production of N gases (e.g. N2O) or leaching losses. Again, the microbial production of N2O is determined by soil moisture and temperature and the availability of ammonium and nitrate, which changes with forest type, age and soil type. Efficient cycling and retention of N is essential in Australian forest systems as the soils are generally nutrient poor. Quantifying how soil microbial rates of ammonification (NH4), nitrification (NO3) and denitrification (N2O) change with different forest types, litter quality and soil conditions is important to understand forest nutrient cycling and better predict nutrient availability with forests age, fire disturbance and climate change.
Aim: Measure soil microbial processes involved N cycling and loss in different forest types and soil conditions.
Experimental design: Field and laboratory experiments
Methods : Stable isotope labelling, respiration and gas sampling.
Honours projects 2007/08 - Forests and Climate Change Research
A research honours project develops a student's ability to design and undertake a substantial body of work, to find solutions to a particular industry or discipline issue, and to report on this in written and verbal form. The project topic is developed in close collaboration between student, academic and industry advisers. Project definition is completed shortly after commencement of the semester of enrolment in the subject, and requires approval from the subject coordinator based on input from academic and industry advisors, taking into account the student's preparation through previous selection of elective or stream subjects.
Students registered in the subject will attend a series of lectures delivered at each campus on research topics. Logistic assistance for projects is coordinated on a case-by-case basis.
Each student prepares a short oral presentation on their project proposal, which is peer-reviewed, as well as a written proposal (5-8 pages) to be assessed by academic and industry advisers. A more detailed oral presentation is presented on the final results of the project to an audience of Faculty and industry staff
1. Salinity tolerance of eucalypts – importance of apoplastic solutes
Osmotic adjustment and intracellular compartmentation are important mechanisms for salinity tolerance of trees. This project will investigate the importance of osmotic adjustment and salt stored in the apoplast in field grown eucalypts that are exposed to salinity. Samples will be collected in national parks and plantations and analysed in the laboratory.
Contact Stefan Arndt (sarndt@unimelb.edu.au) for more information: 03 9250 6819
2. Mechanisms of drought tolerance in eucalypts – active or passive osmotic adjustment
Plants can adapt to drought by lowering their osmotic potential in the leaves. This can either be achieved by a net increase of solutes (active) or an adjustment of the water content (passive). This important mechanism of drought adaptation has scarcely been studied in tree species in Australia. This project will study osmotic adjustment in field grown eucalypts and acacias in different climate zones in Victoria and will consist of two field campaigns (one in Feb/Mar and one May/Jun).
Contact Stefan Arndt (sarndt@unimelb.edu.au) for more information: 03 9250 6819
3. Forest soils and greenhouse gas exchange – soil moisture, temperature and fertility
The exchange of greenhouse gases between forest soils and the atmosphere is greatly determined by soil moisture, soil temperature and fertility. Intact soil cores will be sampled in the from a long-term forest fertiliser study and incubated at different temperatures and moisture contents to investigate the relationship between these controlling mechanisms and methane, nitrous oxide and carbon dioxide emissions.
Contact Steve Livesley (sjlive@unimelb.edu.au) for more information 03 9250 6818
4. Land-use change in Victoria and the greenhouse gas balance
Afforestation from agricultural pastures to forest systems is widespread in parts of Victoria, but the environmental benefits or costs are little understood. Using a paired-site approach, the effect of eucalypt afforestation upon soil nutrient and carbon status and trace gas emissions will be investigated throughout Victoria, on different soil types and rainfall regimes. It will be the first regional field assessment of greenhouse gas emission potential from pasture and plantation forests in Victoria.
Contact Steve Livesley (sjlive@unimelb.edu.au) for more information 03 9250 6818
To Forests and Climate Change Research