Potential Student Projects

The Physiological and Ecosystem Ecology Group currently offers new student projects in the following themes and topics. These can be at the Masters project, Honours project or PhD level.

For more information about the projects and how to obtain scholarships (if available) please contact Stefan Arndt under sarndt@unimelb.edu.au.

Do nitrification inhibitors decrease nitrous oxide emissions from agricultural soils?
Nitrification inhibitors can be effective in reducing emissions of the greenhouse gas nitrous oxide from soils and in enhancing the availability of nitrogen for plants as shown by multiple studies. However, many of these studies have been in the laboratory or on small scales in the field. This project will trial the use of nitrogen fertiliser amended with the nitrification inhibitor DMPP under real farm conditions (dairy pasture, broadacre cropping) in North East Victoria. We will measure the emissions of greenhouse gases under real farming conditions and assess potential changes to the productivity of the system.

Methane uptake of soils
Oxidation of the greenhouse gas methane by methanotorphic bacteria is the only biological sink for this potent greenhouse gas and methane oxidation in forest soils is the largest terrestrial sink. However, we still know very little about this important process. This project will investigate the methane uptake potential of forest soils with different soil properties in order to get a better understanding of the fundamental mechanisms that control methane uptake. This project involves measurements of methane flux in different forest ecosystems around Melbourne and Victoria using greenhouse gas measurement systems.

Methane production by trees
The greenhouse gas methane is produced by methanogenic bacteria under anaerobic conditions and this process is well described for anoxic soils, wetlands, landfills and rice cropping. It has further been shown that plant can act as passive conduits for methane produced in deeper soil layers. However, there is recent evidence that methane can also be produced inside of tree stems where wood rot and anaerobic conditions provide an ideal environment for methane production. Hence, this process can potentially lead to large losses of sequestered carbon and change our conception that forests are generally a methane sink. However, we have not yet quantified this for tree species and forest ecosystems in Australia, where stem rot is quite common in older trees. This project will assess if older eucalypts are producing methane in their stems therefore act as a methane source and how much of the gas is produced in relation to the degree of stem rot.

Methane emissions by termites
Termites can emit large amounts of the greenhouse gas methane from their hindguts but we still only have a partial understand how much of the methane is actually released to the atmosphere. The primary goal of this project is to investigate the extent and magnitude of methane oxidation (uptake) in termite mounds of selected termite species. One key question is how much of termite-produced methane is mitigated in the mound material before reaching the atmosphere. This requires the development and validation of a reliable method for the in-situ quantification of the oxidation potential within a termite mound. In a further step, potential driving factors for methane oxidation in termite mounds will be investigated, together with net methane emissions. The aim is to provide a functional understanding of microbial methane uptake in termite mounds and their dependencies on environmental parameters, leading to a better knowledge base for estimation of the mitigation effect of microbial methane uptake on termite-produced methane.

Vulnerability of eucalypts to tree drought mortality
Climatic changes lead to more prolonged droughts in south-eastern Australia and we already observe significant tree death in many forest ecosystems. Eucalyptus is a very diverse tree genus that occurs in every environment in Australia but many eucalypt species have very narrow climatic ranges. This project will investigate if eucalypts with narrow climatic ranges are more vulnerable to tree mortality than eucalypts with broader climatic ranges and assess the potential plant physiological mechanisms for the vulnerability or resilience of the species. The project will focus on plant water relation traits but other methods or traits can be included as the project progresses.

Mechanisms of drought tolerance in trees
Tree species have different mechanisms to tolerate drought events. Some species can adjust their water potential and withstand very long periods of drought by a continued water use. Other species close their stomata very early in a drought event in order to conserve water. However, it is still unknown how these different strategies are related to the aridity of the environment and how the different mechanisms are interlinked. This project will investigate if tree species that have a high plasticity in regulating water use have different fundamental mechanisms of drought tolerance compared to species that have a low plasticity of regulating water use.

Adaptation of urban trees to environmental stresses
Urban trees provide a large range of important ecosystem services but live in an environment that exposes them to multiple environmental stresses. The many impervious surfaces in cities and recent droughts put many tree species in Melbourne under extreme stress and led to extensive mortality. This project will investigate how different urban tree species adapt to drought and assess their drought tolerance and potential to survive in a drier climate. The project will possibly also assess ways how we can best alleviate drought stress for certain species based on their adaptive mechanisms.

 

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