Tasmanian authorities are working to identify a pink slime that has appeared on a secluded beach, with some scientists concerned it could be an algal bloom.
The pink-tinged sludge appeared along a stretch of Randalls Bay about 60km south of Hobart on Friday morning. A similar sludge has also been recorded on sections of Little Roaring Beach in Tasmania’s D’Entrecasteaux Channel and Little Taylors Bay.
Samples have been taken and provided to Tasmania’s Environment Protection Authority for testing. A spokesperson for the Department of Natural Resources and Environment Tasmania did not clarify when results might be expected, but said “algal blooms are a natural occurrence in response to changes in nutrients, temperature, rainfall or light”.
“They are sometimes called red or pink tides because the blooms can turn the water red,” the spokesperson said. “Not all algal blooms are harmful, with many species acting as a major source of energy for animals in the marine food web.”
“The most common cause of red tides in Tasmanian waters is the marine phytoplankton Noctiluca scintillans, which can cause bioluminescent light displays at night.”
Algal blooms occur naturally but the frequency of such events has increased in recent years, in part due to climate change and pollution that combine to create nutrient-rich waters geared for the rapid spread of dinoflagellates.
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Dinoflagellates are a phytoplankton species that normally act as the ocean’s garbage cleaners. During a bloom, there is a rapid growth in their populations that disrupts the proper operation of ecosystems.
These events have been compared to underwater bushfires and can continue to grow as long as conditions are ripe. In more extreme scenarios, sensitive marine ecosystems can be wiped out as marine life is killed or suffocated, providing more nutrients for the bloom.
South Australia recently grappled with a devastating algal bloom along its southern coastline after a series of marine heatwaves, which spread across thousands of square kilometres. The bloom left surfers with irritated eyes and hacking coughs and may have killed up to 250,000 marine animals across 400 different species, according to SA government calculations revealed in a document released under freedom of information laws.
Faith Coleman, an estuarine ecologist who helped investigate the start of South Australia’s algal bloom said, based on photos of the Tasmanian outbreak, the most likely species involved was Noctiluca scintillans, a type of dinoflagellate also known as “sea sparkle”.
“There have been lots of these blooms around Tassie of late,” she said.
Coleman said sea sparkle did not produce toxins similar to the species involved in South Australia’s devastating algal bloom, but it does eat small invertebrates and “lots of fish eggs”, meaning fish and crustacean species were most at risk.
“You usually see a bloom of sea sparkle after a bloom of something else, or something like a salmon or coral spawning event,” she said.
Lilly Henley, a marine scientist and campaigner with Neighbours of Fish Farming who collected samples of the pink sludge in Tasmania, said it appeared the suspected bloom had “grown significantly” in the last 12 hours and suggested the salmon farming industry was the most likely culprit, pointing to similar cases in Chile.
“So Tasmania needs to send a strong warning here, the government and the EPA need to react to this. We need to analyse the samples we’ve taken and we need to put word out to the public here,” she said.
Henley said she had concerns for public safety after experiencing a tingling sensation along her arms and face while being splashed with contaminated seawater.
The Bob Brown Foundation has reported dead octopus and dead sea cucumbers washing ashore, with longtime environmental campaigner Bob Brown describing the situation as an “environmental emergency” and calling on the Tasmanian premier, Jeremy Rockliff, to visit and “take control of the response that government must be making”.
“[Rockliff] needs to know this is a disaster in the making, economically as well as environmentally.”
Speaking to reporters on Saturday, Rockliff said he was not aware of any links between the algal bloom and the salmon industry, saying scientific testing was needed before conclusions could be drawn.
“We need to ensure our waterways are environmentally safe and sustainable,” he said.
“The 1,200 beaches across Tasmania are our assets and we need to ensure the community and our industry can coexist to utilise our waterways effectively and sustainably.”
– with AAP
