Carbon (C) and nitrogen (N) cycling in estuarine and marine sediments; the role of autotrophic and heterotrophic sediment microbes in processing C and N, including benthic microalgae and anammox and denitrifying bacteria; lipid geochemistry; stable isotope geochemistry; characterization of organic matter; analytical techniques including gas chromatography (GC), mass spectrometry (MS).

 

 

Coastal marine ecosystems receive nutrient and organic matter inputs from diverse sources, making these sites of intense and complex biogeochemical cycling. My aim is to understand the dynamic processes influencing carbon (C) and nitrogen (N) cycling within coastal systems and the impacts of human and climatic processes on these cycles. My research approach combines novel isotopic and organic geochemical techniques in both experimental and field settings to study the sources and fates of C and N in estuarine and marine ecosystems and the role of sediment microbes in processing these nutrients. My research has demonstrated the key buffering role that microbes play, both in terms of C and N retention in microbial biomass and N release through novel processes, such as anaerobic ammonium oxidation (anammox).
 

My current research topics include: 1) the pathways of C and N in shallow photic systems, which are dominated by benthic plants such as seagrass, macroalgae, and benthic microgalgae, 2) the environmental controls of anammox and denitrification in marine sediments, 3) the influence of episodic rain and draught events on benthic productivity and N-cycling pathways in the shallow coastal lagoons along the Texas Gulf Coast.
 

 

Hardison, A., I.C. Anderson, E.A. Canuel, C. Tobias, B. Veuger (2011). Carbon and nitrogen dynamics in shallow photic systems: Interactions between macroalgae, microalgae, and bacteria. Limnology & Oceanography 56:1489-1503.

 

Hardison, A., C. Tobias, J. Stanhope, E. Canuel, and I. Anderson (2011). An experimental apparatus for laboratory and field-based perfusion of sediment pore water with dissolved tracers. Estuaries and Coasts 34:243-255.

 

White, K., N. Lorenz, T. Potts, W.R. Penney, R. Babcock, A.K. Hardison, E.A. Canuel, J.A. Hestekin (2011). Production of Biodiesel Fuel from Tall Oil Fatty Acids via High Temperature Methanol Reaction. Fuel 90:3193-3199.

 

Hardison, A., E. Canuel. Carbon (organic, cycling), (2011). In: Reitner, J., Thiel, V. (eds.), Encyclopedia of Geobiology. Springer, The Netherlands. pp. 230-234.

 

Hardison, A., E. Canuel, I. Anderson, B. Veuger (2010). Fate of macroalgae in benthic systems: Carbon and nitrogen cycling within the microbial community. Marine Ecology Progress Series 414:41-55.

 

Anderson, I., K. McGlathery, A. Hardison, J. Stanhope (2010). Sources and fates of nitrogen in Virginia coastal bays. In: Kennish, M., Paerl, H. (eds.), Coastal Lagoons: Critical Habitats of Environmental Change. Taylor and Francis. pp. 43-72.

 

Hardison, A. E. Canuel, I. Anderson, C. Tobias, B. Veuger, M. Waters (in prep). Benthic algae determine sediment organic matter composition in shallow photic sediments. For submission to: Estuarine, Coastal and Shelf Science.

 

A. Hardison, Stanhope, J.W., I. Anderson, K. McGlathery (in prep). Construction of a nitrogen budget for a temperate coastal lagoon. For submission to: Estuaries and Coasts.