Dr Joanne Oakes
My interest in coastal systems has focussed on the use of stable isotope analysis, primarily to trace fluxes among trophic groups. Initially, I used manipulative experiments to look at the interaction between sulfur within sediments and seagrass tissues to establish causes of variability in sulfur signatures of the seagrass, Zostera capricorni. I also used advanced mixing models to investigate the ability of stable isotopes of sulfur, as well as nitrogen and carbon, to isotopically discriminate between producers for food web studies.
More recently, I have been interested in determining the importance of benthic microalgae and mangroves as carbon sources for estuarine invertebrates. Previous work looking at microalgae encountered difficulties extracting microalgae from sediment to determine pure carbon isotopic signatures. I developed a new technique, using compound-specific isotope analysis of the compound phytol, that is able to accurately determine microalgae carbon signatures whilst avoiding the need for physical separation of microalgae from sediment. I have since applied this method, in combination with a compartment modelling technique, to quantify the use of microalgae by estuarine consumers through large-scale pulse-chase 13C-enrichment experiments. I have also added 13C-enriched mangrove detritus to sediment in a complementary study to quantify the use of mangrove detritus, and have used compound-specific isotope analysis of 13C-enriched fatty acid biomarkers to examine carbon transfer between microalgae and bacteria within sandy and muddy estuarine sediments.
Much of my research has involved the use of mathematical models and manipulative experiments, particularly stable isotope enrichment, to trace fluxes among compartments. Currently, I am working on an ARC project using biomarkers and 15N-enrichment to investigate nitrogen cycling in coastal sediments with a view to determining the potential impact of nutrient enrichment on coastal marine ecosystems.
MAJOR RESEARCH GRANTS
ARC Discovery Early Career Researcher Award
- $375,000 "Unravelling the transformation pathways and fate of dissolved organic carbon and nitrogen in shallow coastal sediments" 2012 to 2014.
- $320,000 (DP0878568) "Unravelling pathways of nitrogen cycling in the muddy sediments of shallow coastal systems using biomarkers, stable isotope tracer experiments and modelling" 2008 to 2010. CI 2 of 2.
-$240,000 (LE130100153) "A liquid chromatography/ gas bench: isotope ratio mass spectrometer for new and novel carbon and nitrogen research in coastal systems" 2013. CI 3 of 5
-$250,000 (LE120100156) "A high precision, automated system for studying greenhouse gas cycling in coastal environments" 2012. CI 4 of 5.
- $170,000 (LE100100013) "Eddy Correlation Lander Array" 2010. CI 5 of 12.
- $220,000 (LE0989952) "A Wet Chemical Oxidation-Isotope Ratio Mass Spectrometer (WCO-IRMS)" 2009. CI 6 of 6.
- $88,100. "Ecological health monitoring of Skennars Head wastewater treatment plant outfall" 2009 to 2010. CI 2 of 2.
Updated: 22 July 2013