Research Interests

Alpine Aquatic Ecology and Peatlands

Our research is critical for future management of the Australian alpine environment. Alpine peatlands are important in regulating stream flows and water quality and will be adversely impacted by climate change. Our work investigates chemical regulation processes that occur in alpine peatlands and associated headwater streams as well as the aquatic communities in these environments. Our recent projects include the response of alpine peatlands and aquatic communities to high intensity rain events.

Characterisation and Bioavailability of Dissolved Organic Matter (DOM)

DOM has an important role in regulating abiotic and biotic processes in aquatic ecosystems. We use a range of fluorescence (EEMs) and absorbance spectroscopy and analytical techniques (LC-MS/MS (amino acid composition and small organic acids) and LC-OCD-OND) to characterise the chemical composition and bioavailability of DOM in aquatic ecosystems. Our current research investigates the influence of tributary inflows on DOM cycling in regulated systems; metabolic dynamics in dryland lowland rivers, amino acid composition of different freshwaters and characterisation of DOM in naturally acidic, circumneutral and groundwater fed systems.

Bioavailability and Toxicity of Contaminants

Contamination of aquatic ecosystems is increasing globally. We use chronic toxicity bioassays coupled with a range of analytical and speciation techniques to assess the toxicity and bioavailability of contaminants (e.g. metals) in aquatic systems. Our current research is directed towards understanding the influence of water quality parameters such as dissolved organic carbon (DOC) in modifying the toxicity of metals and other contaminants. Results from our research go towards improving water quality guidelines.

Macoustra et al. (2019) Environ. Sci. Technol:

Effects of Abiotic Factors on Aquatic Biota

Environmental and anthropogenic factors (temperature, salinity, pH, DOM and contaminants) affect aquatic organisms and biological communities. We use molecular (metagenomics and eDNA) and analytical techniques to study responses of organisms and communities to these factors. Examples include: the effects of water type on fish microbiomes in the Amazon basin; influence of water quality on moss distributions; biofilm responses to DOM composition; metals and environmental stressors effects on the amino acid profiles and proteome of aquatic biota.

Synchrotron-based Techniques

We use Infrared Microspectroscopy (IRM), and X-ray Absorption Spectroscopy (XAS) to study elemental and chemical distributions in sediments and organisms. Synchrotron based methods such as infrared microspectroscopy (IRM), and X-ray absorption spectroscopy (XAS) allow for the in-depth study of aquatic chemical and biological processes. IRM for example is ideally suited to the study of chemical changes in biota in response to changing chemical conditions such as pH or exposure to metals. We have used IRM to explore changes in leaf tissues during decomposition, responses of mosses to their aqueous environment and the effect of metal contaminants on eye tissue in larval fish. XAS is ideally suited to understanding the chemical form of metals in a range of materials (e.g. soils, biological tissues). We have used XAS to determine speciation of arsenic in floodplain sediments affected by historical gold mining and the mineralogy of iron in naturally acidic wetlands.

Bright field photomicrographs and FPA-FTIR transmission images of the mid-vein of E. camaldulensis leaves. Kerr et al. (2013)