Author(s): Yafei Zhu; Perran Cook; Andrew Mccowan; John Beardall; Matthew R. Hipsey
Linked Author(s): Andrew McCowan
Keywords: Hydrodynamics; Stratification; Cyanobacterial Blooms; Salinity; Re-aeration
Abstract: A research project is being undertaken by the Water Studies Centre at Monash University to investigate the dynamics of cyanobacterial blooms in a coastal estuarine lake system, the Gippsland Lakes, by utilising fully coupled 3-D hydrodynamic and biological/ecological models. At the first stage, a hydrodynamic model has been developed and calibrated for the Gippsland Lakes. The model has also been used to simulate the oxygen concentrations in the water column by accounting for atmospheric exchange and applying a constant sediment oxygen demand, with other chemical or biological processes that can affect oxygen balance, such as photosynthesis, having been excluded. The hydrodynamic model has reproduced the observed water levels across the lakes reasonably well. The distribution of salinity in the lakes is highly variable and very sensitive to the immediate hydrodynamics. The modelled surface and bottom salinities are close to the observed ones; however, the thickness of the halocline layer tends to be overestimated. Temperature in the lakes does not have any obvious stratification over the simulation period and it has a larger impact on the surface dissolved oxygen due to its effect on solubility. On the other hand, the bottom dissolved oxygen is more correlated to the bottom water salinity.
Year: 2013