[ad_1]
At a site in Chile’s Atacama Desert called Laguna La Brava, scientists have been analyzing purple photosynthetic microbes that live in ultra-oxygenated, salt-free lake water for some time, writes livescience.com.
“I’ve been working with microbial mats for about 35 years,” said Peter Visscher, a geoscientist at the University of Connecticut. “It is the only system on Earth where I can detect a microbial mat that lives completely without oxygen.”
There have been at least the last 3.5 billion microbial mats on Earth that petrify and turn into stromatolites. years. Only the first billion years of their existence did not contain oxygen for photosynthesis.
How these life forms survived such extreme conditions is still unknown, but after studying existing stromatolites and extremophiles, the researchers believe they have identified several possibilities. Although iron, sulfur, and hydrogen have long been suggested as possible substitutes for oxygen, the unique “arsenotopia” found in two extremely salty lakes in California, Searles and Mono, has allowed arsenic to become a potential contender for an answer.
Stromatolites subsequently detected in the Tumbiana Formation in Western Australia revealed that accumulation of light and arsenic in the run-up to the chamber allowed photosynthesis to take place. The same cannot be said for iron or sulfur.
Last year, Pacific Ocean scientists also discovered an abundant life form that breathes … namely arsenic.
Even La Brava’s way of life is very similar to the purple sulfur bacteria called Ectothiorhodospira sp, which was recently discovered in an arsenic-rich lake in Nevada, that photosynthesize by oxidizing a compound called arsenite and converting it to arsenate.
While more scientific data is still needed to confirm that La Brana microbes also metabolize arsenite, preliminary scientific evidence suggests that the water that flushes these bacterial mats is rich in hydrogen sulfide and arsenic.
If the study authors are right and the microbes in La Brava actually “breathe” arsenic, these life forms would become the first to do so continuously and completely without using oxygen.
Although genomic studies suggest that La Brava bacteria can metabolize arsenic and sulfur, the authors say that reducing arsenate appears to be more effective than reducing sulfate.
However, they say there is researched evidence that both pathways exist, and they would certainly have been sufficient to confirm the existence of abundant microbial mats in the early days of life on Earth.
If this team is right, then the search for life forms should expand elsewhere.
“In search of evidence of life on Mars, scientists will study iron and probably should study arsenic as well,” Visscher said.
It is strictly prohibited to use the information published by DELFI on other websites, in the media or elsewhere, or to distribute our material in any way without consent, and if consent has been obtained, it is necessary to indicate DELFI as the source.
[ad_2]
