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We May Finally Know What Life on Earth Breathed Before There Was Oxygen – ScienceAlert

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Billions of years ago, long before oxygen was readily available, the notorious poison arsenic could have been the compound that breathed new life into our planet.

In Chile’s Atacama Desert, in a place called Laguna La Brava, scientists have been studying a purple ribbon of photosynthetic microbes living in a hypersaline lake that’s permanently free of oxygen.

“I have been working with microbial mats for about 35 years or so,” says geoscientist Pieter Visscher from the University of Connecticut.

“This is the only system on Earth where I could find a microbial mat that worked absolutely in the absence of oxygen.”

Microbial mats, which fossilise into stromatolites, have been abundant on Earth for at least 3.5 billion years, and yet for the first billion years of their existence, there was no oxygen for photosynthesis.

How these life forms survived in such extreme conditions is still unknown, but examining stromatolites and extremophiles living today, researchers have figured out a handful of possibilities. 

While iron, sulphur, and hydrogen have long been proposed as possible replacements for oxygen, it wasn’t until the discovery of ‘arsenotrophy‘ in California’s hypersaline Searles Lake and Mono Lake that arsenic also became a contender.

Since then, stromatolites from the Tumbiana Formation in Western Australia have revealed that trapping light and arsenic was once a valid mode of photosynthesis in the Precambrian. The same couldn’t be said of iron or sulphur.

Just last year, researchers discovered an abundant life form in the Pacific Ocean that also breathes arsenic. 

Even the La Brava life forms closely resemble a purple sulphur bacterium called Ectothiorhodospira sp., which was recently found in an arsenic-rich lake in Nevada and which appears to photosynthesise by oxidising the compound arsenite into a different form -arsenate.

While more research needs to verify whether the La Brava microbes also metabolise arsenite, initial research found the rushing water surrounding these mats is heavily laden with hydrogen sulphide and arsenic.

If the authors are right and the La Brava microbes are indeed ‘breathing’ arsenic, these life forms would be the first to do so in a permanently and completely oxygen-free microbial mat, similar to what we would expect in Precambrian environments.

As such, its mats are a great model for understanding some of the possible earliest life forms on our planet. 

While genomic research suggests the La Brava mats have the tools to metabolise arsenic and sulphur, the authors say its arsenate reduction appears to be more effective than its sulfate reduction.

Regardless, they say there’s strong evidence that both pathways exist, and these would have been enough to support extensive microbial mats in the early days of life on Earth.

If the team is right, then we might need to expand our search for life forms elsewhere.

“In looking for evidence of life on Mars, [scientists] will be looking at iron and probably they should be looking at arsenic also,” says Visscher.

It really is so much more than just a poison.

The study was published in Communications Earth and Environment

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COVID-19: Okanagan resort closes temporarily after staffer tests positive – Revelstoke Review

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Sparkling Hill Resort is closing for 11 days Friday after a staff member tested positive for COVID-19.

The popular tourist destination said its immediate closure effective Friday, Oct. 30, is a proactive and precautionary measure.

“Due to the extensive COVID-19 plan in place at the resort, Interior Health confirmed there is no concern for any guests that stayed recently,” the resort said in a statement.

The individual contracted the novel coronavirus outside the resort and immediately self-isolated. Any other staff members who were in close contact with the affected member of staff have been identified and contacted by the regional health agency with information and advice.

The resort will resume operations Monday, Nov. 9.

Any guests who have upcoming reservations will be contacted and provided with options.

“The health and safety of our staff, guests and community are a top priority,” the statement reads. “While the closure is not required by Interior Health, the immediate actions are taken to ensure there is no further spread of the virus.”

In September, the resort was notified a guest that had recently visited had tested positive for COVID-19 (Sept. 3).

READ MORE: COVID-19 case confirmed at Vernon’s Sparkling Hill Resort

READ MORE: Hunters free themselves from rollover on Westside


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COVID-19: Okanagan resort closes temporarily after staffer tests positive – Summerland Review

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Sparkling Hill Resort is closing for 11 days Friday after a staff member tested positive for COVID-19.

The popular tourist destination said its immediate closure effective Friday, Oct. 30, is a proactive and precautionary measure.

“Due to the extensive COVID-19 plan in place at the resort, Interior Health confirmed there is no concern for any guests that stayed recently,” the resort said in a statement.

The individual contracted the novel coronavirus outside the resort and immediately self-isolated. Any other staff members who were in close contact with the affected member of staff have been identified and contacted by the regional health agency with information and advice.

The resort will resume operations Monday, Nov. 9.

Any guests who have upcoming reservations will be contacted and provided with options.

“The health and safety of our staff, guests and community are a top priority,” the statement reads. “While the closure is not required by Interior Health, the immediate actions are taken to ensure there is no further spread of the virus.”

In September, the resort was notified a guest that had recently visited had tested positive for COVID-19 (Sept. 3).

READ MORE: COVID-19 case confirmed at Vernon’s Sparkling Hill Resort

READ MORE: Hunters free themselves from rollover on Westside


@caitleerach
Caitlin.clow@vernonmorningstar.com

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Well-known Okanagan resort voluntarily closes following positive COVID-19 test – Global News

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One of the Okanagan’s better-known resorts has temporarily closed its doors following a positive COVID-19 test.

In a statement issued Friday, Sparkling Hill Resort in Vernon said it was closing for 11 days following a positive test by a staff member.

The closure was effective immediately, Friday, Oct. 30, and was being called a “proactive and precautionary measure” for the continued safety of its guests, staff and vendors.

Read more:
B.C. adds 272 new COVID-19 cases, grants powers for region-specific health orders

“The precaution comes as a result of Interior Health informing the resort on Oct. 30 of a confirmed case of COVID-19 with one staff member,” the resort said.

According to the resort, the staff member contracted COVID-19 outside of the resort and started self-isolating immediately.

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It added that “due to the extensive COVID-19 plan in place at the resort, Interior Health confirmed there is no concern for any guests that stayed recently.”


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The resort also said staff members who had been in close contact with the affected staff member have been identified and contacted by Interior Health.

The resort expects to resume operations on Monday, Nov. 9, adding that the closure was voluntary and not required by Interior Health.

Contacted by Global News, Interior Health said that it has not ordered any businesses to close, adding they may choose to close on their own.


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