The Van Diemen Gulf, located between Melville Island, the Cobourg Peninsula and the mainland, is a poorly flushed, semi-enclosed embayment characterised by shallow coastal waters (<30m) and a large tidal range (3-8m).
The surrounding catchments from the East and South Alligator, Adelaide and Mary rivers contribute to significant freshwater discharges carrying sediments and nutrients during the wet season into the Gulf. Concentrations in suspended sediments, coloured dissolved organic matter and chlorophyll vary dramatically between the wet and dry season, likely resulting from seasonal differences in water column mixing, turbidity, productivity, salinity, waves and wind-driven surface currents.
Similarly to the Van Diemen Gulf, Darwin Harbour is a complex transition zone between riverine and coastal ocean waters. Undergoing large developments from industry and tourism, a detailed understanding of its ecosystem functioning and variability over space and time is needed. Ocean colour remote sensing is the only technique capable of monitoring the quantity, cyclicity and spread of water quality parameters over large scales of space and time.
The high temporal frequency at which satellite images are acquired allow for the integration of climatology maps and time series of satellite-derived surface water properties that are used for detecting annual and seasonal trends. This seminar will present some of the results obtained for the Van Diemen Gulf and Darwin Harbour regions from a 10-year ocean colour satellite dataset and field campaigns.