Laboratory-based investigation into the potential for algal proliferation in Lake Coleman, Victoria

Abstract

Lake Coleman received a discharge of highly coloured, treated pulp and paper mill effluent and domestic and industrial effluent from 1958 until the latter part of 1992. The colour of the lake waters is likely to become less intense following cessation of the discharge and this may affect the potential for algal growth. The estuarine diatom Phaeodactylum tricornutum was cultured in a range of concentrations of Lake Coleman water with and without pre-exposure to nutrient-rich Lake Coleman sediments. Under laboratory conditions, growth of P. tricornutum was significantly enhanced in Lake Coleman water compared with cultures grown in water collected from an adjacent unpolluted lake. Growth was further enhanced in solutions with additional pre-exposure to Lake Coleman sediments. Growth enhancement exhibited a linear relationship to solution orthophosphate concentrations. When the diatom was cultured under a range of light intensities produced by a range of dilutions of Lake Coleman water, growth was significantly reduced by high colour intensity. The possibility exists, therefore, for enhanced algal proliferation in Lake Coleman following cessation of effluent discharge.