The effects bushfires have on aquatic ecosystems can occur over long timeframes.
Our water quality monitoring buoys collect data on water quality which is helping us assess the ecological health of estuaries, including the long-term impacts of bushfire.
The 6 estuaries we are monitoring are intermittently closed and open lakes and lagoons, or ICOLLs. They all have relatively deep basins and their catchments were extensively burnt in the 2019–20 black summer, except for Avoca Lake.
This monitoring work will help us work out whether ICOLLs are more susceptible to increases in ash, sediment and nutrient input from bushfires because they are not flushed by seawater as often as some other estuaries.
Early results indicate that these ICOLLs are naturally prone to stratification – the distribution of water into different layers.
Stratification particularly occurs in deeper estuaries where oxygen-depleted, nutrient-rich bottom water persists for most of the time. When water in these deeper ICOLLs ‘turns-over’, or becomes mixed due to flooding or sharp temperature changes, this can stir up nutrients and trigger large algal blooms.
Work is continuing to establish to what extent post-fire sediment and nutrients exacerbate these processes, and perhaps contribute to ongoing water quality issues.
See our Real-time water quality monitoring webpage for more information on the buoys, including real-time data links.