Swimmers hoping to take a dip at Bondi Beach in Australia were disappointed (and likely somewhat disturbed) to see that blood red water had temporarily shut it down.
The blood red waters are the result of a natural phenomenon called “red tide,” which happens when red algae bloom pops up close to shore, reports The New York Daily News.
The blood red waters shut down Bondi Beach, as well as several other well-known beaches around Sydney. Thankfully the rare spectacle, which is more formally known as noctuluca scintillans (or sea sparkle), is not toxic to humans.
Despite it not being toxic, people are still asked to stay away from the red tide because the algae contains high levels of ammonia that can cause skin rashes and eye irritation. Lifeguard Bruce Hopkins stated:
“It has got quite a fishy smell to it. It can irritate some people’s skin but generally not much more than that.”
The blood red waters can sometimes be caused by warm, humid weather, but with Australia’s summer just getting started, the idea seems unlikely. The New South Wales (NSW) Office of Water has been conducting a series of tests on the algae bloom to discover what caused it, according to The Daily Mail.
One of the office’s theories is that the unusual red tide was caused by an upwelling of colder nutrient-rich water. The blooms are much more common in spring and autumn when the water temperature is higher and the ocean currents have greater movement.
While the blood red waters are not toxic to humans, it is probable that high numbers of fish have been killed off because of it. A spokesman for Sydney’s local council stated that the red algae can be dangerous to humans. They stated:
“There are some possible risks to human health including skin rashes and eye irritation and for this reason the beach will remain closed until the algae dissipates.”
Officials are hopeful that the blood red waters on Bondi Beach and other areas in Sydney will dissipate by the weekend.