The Waring Gardens lagoon has been taken over by an aquatic plant called azolla. While not dangerous, it can be problematic.
Have you noticed the lagoon in the Deniliquin Waring Gardens is slowly turning red?
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Resident ecologist and Deniliquin Kolety Lagoons Landcare Group member Dr John Conallin says while it looks a little sinister, there’s nothing to worry about.
It’s not an algae and it’s not dangerous.
Dr Conallin said it is a native aquatic plant called azolla, which is more commonly referred to as duck weed.
It is often found in still or slow-moving water bodies and can appear green or red, depending on exposure to the sun.
It’s common in dams, and is also sometimes found in the Edward River.
The azolla plant supports nitrogen fixing bacterium, which allows it to use nitrogen from the water and air for its own growth.
Azolla is not harmful to wildlife or stock that drink the water or consume the plant, and does not harm domestic house and garden water.
Azolla, commonly known as duckweed, can appear red or green.
However, excess growth of the plant can significantly alter the physical and chemical properties of water. And as it dies, it actually reduces oxygen levels in the water.
Dense mats of the weed - which can be dispersed by weather conditions or by attaching to wildlife or humans - can also block pump inlets and filters, impede water flow and reduce sunlight penetration of waters.
Dr Conallin said its removal is not a simple process.
“We can’t just spray it like you might do with a weed in the garden,” he said.
“It has to be removed from the lagoons manually, and takes a bit of work.”
Dr Conallin said he would continue to investigate the best way to remove and manage azolla in the lagoon system in partnership with Deniliquin Kolety Lagoons Landcare Group partners.
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