EVENT: Source and Reactivity of Dissolved Organic Matter in the Swan-Canning Catchments and Estuary Using Fluorescence Spectroscopy

Dissolved organic matter (DOM), observed as tannin or tea coloration in surface waters, is ubiquitous in rivers and estuaries of South-western Australia. Local concentrations of DOM, including carbon (DOC) and nitrogen (DON), are especially high compared to global averages, yet their role in river and estuary ecosystem function are not well understood. In this seminar, we present recent findings on the composition and reactivity of DOM in the Swan-Canning catchments and estuary. Using fluorescence techniques, we show that humic and amino acid fluorescence components can be used to identify distinct catchment and estuarine DOM sources that are also related to the degree of DOM biodegradation. Lastly, we will discuss how future changes in climate and urban/agricultural land-use may influence carbon and nutrient cycling with important implications for the Swan-Canning ecosystem.