2022-02-08 Planning and Environment Committee Meeting Agenda

PLANNING & ENVIRONMENT COMMITTEE MEETING AGENDA   8 FEBRUARY 2022




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PLANNING & ENVIRONMENT COMMITTEE MEETING AGENDA                                       8 FEBRUARY 2022

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              Figure 1: Clean-up efforts of nuisance algae blooms on Noosa Main Beach 2005 (Photograph by
                                                  Graeme Parkes).

           1.2    Nutrients and Algal Blooms
           Nutrient enrichment can cause prolific plant growth, clogged waterways, nuisance algal blooms, low
           oxygen events, fish kills and a general deterioration in water quality. Nitrogen and phosphorus are
           the ‘culprit’ nutrients, but nitrogen is most important in controlling plant growth in estuaries (Dobson
           and Frid, 1998). The Hincksia sordida species is very efficient at processing nitrogen (Phillips, 2006)
           and has the advantage over other species of algae to uptake nutrients such as nitrogen and rapidly
           form blooms (Elgin and Associates Pty Ltd, 2013). The blooms can last weeks or months with algae
           forming dense accumulations in the water and constantly washing onto beaches by prevailing winds
           and surface water movement.

           The sources of nitrogen causing the Laguna Bay blooms has not been identified. Typical sources
           include:
              e   Catchment run-off from urban and rural land uses
              e   Effluent discharge from wastewater treatment plants
              e   Groundwater discharge
              e   Mobilisation of embedded nutrients from the sea bed or river bed (benthic zones) during
                  temperature inversion events, transport mechanism (e.g.Ekman transport) or other
                  disturbances (e.g. storms, dredging).

           This lack of understanding of the nutrient cycle is further explored in the report below.

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