THIS is the moment shocked and confused Aussies discovered blood red seawater in a city harbour
The footage shows foaming bright red waves lapping around the base of a wooden pier in Sydney.
Water in Sydney harbour mysteriously turned bright red and locals feared the worst[/caption]
The stained water lapped up against boats and homes[/caption]
Alarmingly, the tainted water flowed right up to homes and valuable boats in the harbour.
The source of the swirling scarlet stream remains a mystery – even to the experts roped in – making it all the more terrifying.
The unsettling colour stained the waters of Careening Cove, which flows through a wealthy suburb of Sydney.
The water was flowing into the harbour from Milson Park on the lower north shore.
Horrified witnesses reported the sight to the North Sydney Council, but it has been unable to offer a concrete explanation.
A spokesperson said: “Council is aware of the red water flowing into the harbour from Milson Park, and officers have investigated but have not been able to find the source.”
In a search for answers the scene the New South Wales Environmental Protection Authority (EPA) was called in.
Their investigation is underway, and the unit has come up with a possible explanation.
The EPA said: “North Sydney Council alerted us to what appears to be red plumbers’ dye in a drain at Kirribilli this afternoon and we are currently investigating the potential source.”
They suspect the ruby red hue was caused by a dye that plumbers use, called fluorescein, to help them chart water flow.
Fortunately, the EPA said the chemical has “low toxicity”.
It warned that fluorescein should only ever be used in “minimal” quantities because “even small amounts can be highly visual”.
However, this is just a theory, and locals are still looking to be reassured by firm answers.
This is not the first time Aussies have been startled by bright red shores.
In 2012, the waters around several Australian beaches turned bright crimson.
In that case the sand beaches were also stained red as the algae washed ashore.
Bondi Beach was one of those affected.
Experts analysed the scene and concluded the colouration was caused by thick blooms of algae.
These algae formations are aptly named “red tide” or “fire in the sea”.
Despite reassurances that the algae was not toxic, local officials played it safe by banning people from swimming in the water.
Scientists think the bumper bloom was caused by unusually high water temperatures and stronger ocean currents.