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Old 18-11-2017, 08:58 AM
gary
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Living stromatolites discovered in Tasmanian World Heritage Area

Some readers may have seen the living stromatolites at Hamelin Pool in
Shark Bay, Western Australia, just off the road out to Monkey Mia.

Stromatolites are the oldest evidence for life on Earth.

Though the fossil record shows they were abundant on Earth 3.5 billion
years ago, today living ones are rare.

Therefore it has come as a surprise for researchers to discover living
stromatolites in a remote valley in the south-west of Tasmania within
the Wilderness World Heritage Area.

The discovery has been reported in a paper in Nature.

Press release here :-
http://www.media.utas.edu.au/general...smanian-valley

Full story here by Stephanie Pappas at Living Science:-
https://www.livescience.com/60962-li...e=notification

Quote:
Originally Posted by Stephanie Pappas at Living Science
Earth's first known life was relatively simple: microbial mats that grew in wavy layers, leaving thin pancakes of excreted minerals stacked between them. Stromatolites, as these microbial colonies are known, first appeared on the planet at least 3.5 billion years ago. They're all over the fossil record, but today, they live almost nowhere except for a few shallow, extra-salty marine spots like Hamelin Pool in Shark Bay, Western Australia.

That's why scientists were surprised to stumble across these life-forms in a freshwater wetland in Tasmania in 2015.

The researchers had discovered these living stromatolites — greenish-yellow rounded structures only 4 inches (10 centimeters) across at their largest — thriving on damp, porous rock in the Giblin River valley in southwestern Tasmania. It's an isolated place, said study researcher Bernadette Proemse, a freshwater ecologist at the University of Tasmania, who, along with her colleagues, described this unexpected discovery on Nov. 13 in the open-access journal Scientific Reports.

"The valley we found these stromatolites in is pretty much as remote as you can get in Tasmania," Proemse told Live Science. "It's over about 100 kilometers [62 miles] from the nearest street."
Open access scientific report at Nature entitled "Stromatolites on the rise in peat-bound karstic wetlands" by Bernadette C. Proemse, et. al. here :-
https://www.nature.com/articles/s41598-017-15507-1

Quote:
Originally Posted by Proemse

Stromatolites on the rise in peat-bound karstic wetlands


Abstract

Stromatolites are the oldest evidence for life on Earth, but modern living examples are rare and predominantly occur in shallow marine or (hyper-) saline lacustrine environments, subject to exotic physico-chemical conditions.

Here we report the discovery of living freshwater stromatolites in cool-temperate karstic wetlands in the Giblin River catchment of the UNESCO-listed Tasmanian Wilderness World Heritage Area, Australia.

These stromatolites colonize the slopes of karstic spring mounds which create mildly alkaline (pH of 7.0-7.9) enclaves within an otherwise uniformly acidic organosol terrain.

The freshwater emerging from the springs is Ca-HCO3 dominated and water temperatures show no evidence of geothermal heating.

Using 16 S rRNA gene clone library analysis we revealed that the bacterial community is dominated by Cyanobacteria, Alphaproteobacteria and an unusually high proportion of Chloroflexi, followed by Armatimonadetes and Planctomycetes, and is therefore unique compared to other living examples.

Macroinvertebrates are sparse and snails in particular are disadvantaged by the development of debilitating accumulations of carbonate on their shells, corroborating evidence that stromatolites flourish under conditions where predation by metazoans is suppressed.

Our findings constitute a novel habitat for stromatolites because cool-temperate freshwater wetlands are not a conventional stromatolite niche, suggesting that stromatolites may be more common than previously thought.
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