New research suggests that early life that evolved out of the ocean depths might have evolved to survive the acidic volcano environments, and it could help scientists understand ancient environments on Mars.
Many wouldn't consider acidic lakes in the shadow of a volcano as a conducive habitat. However, early creatures that abandoned the sea would disagree.
Early Days of Life
Many vital information on how the earliest days of life on land thrived is lost to us. What geologists know is that roughly 3 billion years ago, during the Mesoarchean Era, the first continents emerged from the oceans and were soon covered in life.
Unfortunately, only a few rocks that recorded details of the era's environment survived.
Keyron Hickman-Lewis, a geologist from the Natural History Museum, London, says, "It's unfortunate because the era was a major juncture in Earth history."He explains that major geobiological and geological revolutions happened during the Mesoarchean Era.
Today, researchers led by Andrea Agangi from the Akita University, Japan suggested that shortly after life emerged from the seas they quickly adapted to survive in acidic volcanic lakes.
The research published in the journal Earth and Planetary Science Letters stems from the geochemical analysis of 3 billion-year-old sedimentary rocks from the Witwatersrand Basin in South Africa.
Despite the study not being the first or oldest evidence of life, they reveal a new habitat where early microbes might have adapted.
Hickman-Lewis says, "It implies that at this crucial juncture, there was diverse life."
Agangi and his colleagues focused on the Dominion Group, rock formations that assembled during the Mesoarchean Era on what some refer to as the oldest crust on the planet--south Africa's Kaapvaal Craton. Although the Dominion Group consisted of mostly volcanic rocks, researchers were intrigued with the bed of sedimentary rock local miners know as Wonderstone.
In three quarries, the team found walls of Wonderstone that can reach up to ten meters tall. It mostly consisted of shales and sandstones, which researchers interpreted as debris of erosion from the volcano that skin into a large lake. The lake is estimated to have existed tens of millions of years after continents emerged from the sea.
Agangi explains, "The Wonderstone is dark, almost black, and soft. It can easily be crushed by a knife." He explains that the color comes from carbon-rich materials interspersed between rock grains.
Despite miners exploiting Wonderstone deposits for several decades, the origins of the carbon-rich material remained a mystery.
Upon investigation, researchers discovered that the carbon in the rocks came from dead microorganisms. They also discovered that the carbon profile matched profiles of methane-producing organisms known as methanogens.
These microbes belong to an ancient domain called Archaea that are known for their ability to survive harsh conditions.
The resiliency of life forms made sense for researchers as minerals disperse throughout the Wonderstone like pyrophyllite and marcasite indicated that the lake was probably acidic.
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