Climate change researchers awed by pristine Blue Lake on North Stradbroke Island

Updated

Scientists are in awe after discovering a Queensland lake that has barely been affected by changes in climate for 7,000 years.

Key points Blue Lake is on North Stradbroke Island, off the coast of Brisbane

Scientists found lake's chemistry has changed very little over 7,500 years

Study looked at fossil pollen and fossil algae as proxies for environmental change

Lake drains into a swamp and is refreshed by an aquifer, so does not evaporate or become more saline

The researchers from Adelaide and Queensland were studying how freshwater systems respond to drought when they made the discovery at the Blue Lake on North Stradbroke Island.

Researcher Cameron Barr from the University of Adelaide says other freshwater ecosystems varied dramatically because of human interference and climate change.

But he says there was little shift in the depth, shoreline or water chemistry of Blue Lake.

"To our knowledge, this is the only lake like this in Australia that has shown such a stability over such a long period of time," he said.

"We expected some change, given the magnitude of environmental changes over that period, so it was a surprise to find almost none.

"We looked at lots of different proxies of environmental change, such as fossil pollen. But we also looked at fossil algae, these things called diatoms. Diatoms are very, very susceptible to changes in water chemistry.

"What we've found by looking at these diatoms, how they changed over time, is that there was very little change in the chemistry of the lake over the last 7,500 years.

"So to our knowledge, this is the only lake like this in Australia that has shown such a stability over such a long period of time."

He says the lake is a "climate refuge".

"Australian freshwater ecosystems, by their nature and by the nature of the climate which affects them, are variable," he said.

"This place seems to be quite unique in that it shows such an amount of stability. So in that sense it's a refuge for freshwater biota away from those variable environments.

"And we would argue that it's likely to be a freshwater refuge for some time in the future if managed properly."

Dr Barr says the lake drains into a swamp and is refreshed by an aquifer, helping it to remain unchanged.

"Because it's constantly being updated it doesn't suffer from the vagaries of the climate in so far as it doesn't evaporate and become more saline," he said.

"It doesn't fill up and become fresher. It just remains constant."

The peer-reviewed research has been published in the journal Freshwater Biology.

Topics: environment, environmental-impact, academic-research, research-organisations, science-and-technology, university-and-further-education, climate-change, qld, sa, brisbane-4000, dunwich-4183, adelaide-5000, australia

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