HR: 0800h
AN: B41A-0025    [Abstracts]
TI: Measuring Greenhouse Gas fluxes and Carbon and Nitrogen Cycling In Situ in an Estuarine Lake
AU: * Mills, A R
EM: arm00@uow.edu.au
AF: Centre for Atmospheric Chemistry, Department of Chemistry, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
AU: Wilson, S R
EM: swilson@uow.edu.au
AF: Centre for Atmospheric Chemistry, Department of Chemistry, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
AU: Jolley, D F
EM: djolley@uow.edu.au
AF: GeoQuEST, Department of Chemistry, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
AB: A system allowing the in situ quantification of the nitrogen cycle and various carbonaceous species in the air, water and sediment has been developed and deployed in the field to monitor the effects of sediment disturbance on the nitrogen and carbon cycles. Fluxes of nitrous oxide, methane and carbon dioxide were monitored continuously in situ at nearshore sites within a nutrient rich estuarine lake for periods in winter 2006, summer 2007 and winter 2007. Changes in these gas phase fluxes were compared with variations in aqueous and sedimentary carbonaceous and nitrogenous concentrations (OrgN, OrgC, NH₃ and NO₃^- + NO₂^-) and examined in terms of carbon and nitrogen biogeochemical cycling. Links between greenhouse gas production, carbon and nitrogen cycling, water temperature, light availability, pH and dissolved oxygen concentration were also studied. The effect of sediment disturbance was also investigated with significant increases in the concentrations of aqueous NH₃ and NO₃^- + NO₂^- evident. Nearshore sediments were found to act as both a source and a sink of atmospheric nitrous oxide.
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0438 Diel, seasonal, and annual cycles (4227)
DE: 0442 Estuarine and nearshore processes (4235)
DE: 0452 Instruments and techniques
DE: 0469 Nitrogen cycling
SC: Biogeosciences [B]
MN: 2007 Fall Meeting