Restoring aquatic plants and removing algal blooms

The problem

Aquatic plants are a key component of the Coorong ecosystem, providing habitat for fish, food for waterbirds, and improving water quality. Since the Millennium Drought, the health and extent of aquatic plant communities have decreased in the Coorong, mainly due to inadequate water flows, water levels, poor water and sediment quality, and the resulting impacts of blooms of algae and other microbiota.

What we are doing

Research is currently being undertaken to understand the reasons behind the spread of filamentous green algae in the Coorong and how we can move the Coorong from an algal dominated environment back to an aquatic plant dominated environment. Research will investigate how filamentous green algae and aquatic plants respond to temperature, water quality changes and different sediment types. Scientists have investigated innovative methods to map the extent of aquatic plants and algal blooms, and to control algae and prevent it from interfering with seed production in native aquatic plants.

What we have done so far

Key developments and findings from investigations so far include:

  • Development of a new method to detect and map floating algae in the Coorong via satellite imagery, which will be used to monitor changes over time and help us understand the conditions under which algal blooms occur.
  • Evidence that filamentous algae is now attaching to aquatic plants throughout much of the Coorong, reducing seed production and germination of new plants.
  • Evidence from laboratory experiments that algal growth can be controlled under specific temperature, salinity and nutrient conditions.
  • Small-scale trials to remove filamentous algae in the Coorong have been undertaken to assess short-term approaches to reduce the impact of algal blooms.
  • Updated models are being developed to improve our ability to predict the impacts of water quality and flow conditions on aquatic plants.

This information will be used to develop a strategy to restore native aquatic plant communities in the Coorong in order to provide key habitat and food for fish and birds. It will also be used in modelling to inform the short and long-term management options currently being investigated to improve the health of the Coorong. 

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