Dr Joanne Oakes

RESEARCH INTERESTS

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.

ARC Discovery

- $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.

ARC LIEF

-$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.

Other

- $88,100. "Ecological health monitoring of Skennars Head wastewater treatment plant outfall" 2009 to 2010. CI 2 of 2.

PUBLICATIONS

Refereed Journal Articles

2012

Oakes, J. M., Eyre, B. D., and Middelburg, J. J. Transformation and fate of microphytobenthos carbon in subtropical shallow subtidal sands: A 13C-labeling study. Limnology and Oceanography 57, 1846-1856. JIF = 3.66; (ERA Rank A).

2011

Oakes, J. M., Bautista, M. D., Jones, W. B., Maher, D., and Eyre, B. D. Carbon self-utilisation may assist Caulerpa taxifolia invasion. Limnology and Oceanography 56,1824-1831. JIF = 3.66; (ERA Rank A).

Eyre, B. D., Maher, D., Oakes, J. M., Erler, D. V. and Glasby, T. Differences in benthic metabolism, nutrient fluxes and denitrification in Caulerpa taxifolia communities compared to uninvaded sediment and seagrass (Zostera capricorni). Limnology and Oceanography 56,1737-1750. JIF = 3.66; (ERA Rank A).

Oakes, J. M., Eyre, B. D., and Ross, D. J. Short-term enhancement, and long-term suppression, of denitrification in estuarine sediments receiving primary- and secondary-treated paper and pulp mill discharge. Environmental Science and Technology 45, 3400-3406. JIF = 4.363. (ERA Rank *A).

Eyre, B. D., A. J. P. Ferguson, A. Webb, D. Maher and J. M. Oakes. 2011. Denitrification, N-fixation and nitrogen and phosphorus fluxes in different benthic habitats and their contribution to the nitrogen and phosphorus budgets of a shallow oligotrophic sub-tropical coastal system (southern Moreton Bay, Australia). Biogeochemistry 102, 111-133. doi: 10.1007/s10533-010-9425-6. JIF=2.771. (ERA Rank A).

Eyre, B. D., A. J. P. Ferguson, A. Webb, D. Maher and J. M. Oakes. 2011. Metabolism of different benthic habitats and their contribution to the carbon budget of a shallow oligotrophic sub-tropical coastal system (southern Moreton Bay, Australia). Biogeochemistry 102, 87-110. doi: 10.1007/s10533-010-9424-7. JIF=2.771. (ERA Rank A)..

2010

Oakes, J. M., Eyre, B. D., Ross, D. J. and Turner, S. D. 2010. Stable isotopes trace estuarine transformations of carbon and nitrogen from primary- and secondary-treated paper and pulp mill effluent. Environmental Science and Technology 44, 7411-7417. doi: 10.1021/es101789v. JIF = 4.630 (ERA Rank A*)

Oakes, J. M., Eyre B. D., Middelburg J. J., Boschker H. T. S. 2010. Composition, production, and loss of carbohydrates in subtropical shallow subtidal sandy sediments: Rapid processing and long-term retention revealed by 13C-labeling. Limnology and Oceanography 55, 2126-2138. doi: 10.4319/lo.2010.55.5.2126. JIF = 3.545 (ERA Rank A)

Oakes, J. M., Connolly, R. M. and Revill, A. T. 2010. Isotope enrichment in mangrove forests separates microphytobenthos and detritus as carbon sources for animals. Limnology and Oceanography 55, 393-402. doi: 10.4319/lo.2010.55.1.0393. JIF = 3.545 (ERA Rank A)

2005

Oakes, J. M., Revill, A. T. and Connolly, R. M. 2005. Measuring carbon isotope ratios of microphytobenthos through compound-specific stable isotope analysis of phytol. Limnology and Oceanography: Methods 3, 511-519. JIF = 1.737 (ERA Rank B)

2004

Oakes, J. M. and Connolly, R. M. 2004. Causes of sulfur isotope variability in the seagrass, Zostera capricornia. Journal of Experimental Marine Biology and Ecology 302, 153- 164. doi: 10.1016/j.jembe.2003.10.011. JIF = 2.116 (ERA Rank B)

Connolly, R. M., Guest, M. A., Melville, A. J. and Oakes, J. M. 2004. Sulfur stable isotopes separate producers in marine food-web analysis. Oecologia 138, 161-167. doi: 10.1007/s00442-003-1415-0. JIF = 3.129 (ERA Rank A)

Technical Reports

Oakes, J. M. and Eyre, B. D. 2009. Potential for ecological health impacts of discharges from Skennars Head Wastewater Treatment Plant. Report to Ballina Shire Council. Centre for Coastal Biogeochemistry Report No. 2009-02. 25p.

Oakes, J. M., Eyre, B. D. 2010. Receiving waters ecological health monitoring program for the Skennars Head wastewater treatment plant: Interim report. Report to Ballina Shire Council. Centre for Coastal Biogeochemistry Report No. 2010-01. 6 p.

Updated: 20 February 2013