A Border scientist has revealed the algal bloom stretching from Lake Hume to Mildura has never been the predominant species in an outbreak on the Murray River.
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Charles Sturt University institute for land, water and society professor Robyn Watts said the specific cyanobacteria was called chryosporum ovalisporum and it was now breaking down.
She said the species had been reported in other parts the world like the Mediterranean Sea, which separates Africa and Europe.
“This particular species is making up 97 to 99 per cent of the algae,” Professor Watts said.
“What happens in a bloom is one species ... basically takes over.
“There’s thousands of different species and cyanobacteria in the water … this is the first time they’ve had a nuisance bloom from this species.”
Professor Watts was two years into a project about environmental water flows in the Edward-Warkool River system, near Deniliquin, when the outbreak started.
With additional support from the Commonwealth Environmental Water Office, the CSU team has been able to expand its scope to include additional weekly reporting about the bloom since March.
Although they are one of the many organisations monitoring levels of algae along the river, professor Watts said her team was different because of the additional data it was capturing.
CSU’s monitoring equipment means it can examine data such as dissolved oxygen, carbon and nutrients levels from before, during and after the bloom.
“Adding in this extra monitoring, means we can try and understand what's going on with the bloom a bit better rather than just recording levels,” Professor Watt said.
“We've been able to follow what happened as the bloom started to increase ... some of the samples had over a one million cells of cyanobacteria per millilitre.”
Professor Watt said the team’s work would help it understand what the effect on oxygen levels in waterways from chryosporum.
“If it breaks down quickly, than you get other bacteria that consume it and you suddenly get a big drop of oxygen in the water … so you can get a fish kill,” she said.
With no fish deaths yet, Professor Watt hoped there would be no sudden drops in oxygen when the bloom began to die off.
UPDATE: An earlier version of this article identified the species as chryosporum ovalisorum when it was chrysosporum ovalisporum.
