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Imagine a completely barren world. Before you is a volcanic landscape devoid of flora and fauna. There are shallow water bodies scattered across this gray and black wide area. In each of these natural pools, a delicate mix of chemicals and physical conditions come together that may be the source of life on our planet.
Some scientists have theorized that when life first emerged on Earth about 4 billion years ago, the landscape may have looked more like an ocean environment than an ocean environment, and a study around a modern-day lake in the Canadian province of British Columbia offers new suggestions. support this idea.
According to University of Washington professor David Catling, one of the authors of the study, the shallow and salty body of water located on the volcanic rock known as Last Chance Lake carries clues that carbonate-rich lakes in the ancient Earth may have been the “cradle of life”. earth sciences. The finding, published Jan. 9 in the journal Nature, could advance scientific understanding of how life began.
“We were able to look for specific conditions that humans use to synthesize the building blocks of life in nature,” Catling said. “We think we have a very promising lead for the origin of life.”
Catling and his colleagues first became aware that the lake was a place to focus their research after a literature review uncovered an unpublished master’s thesis in the 1990s that had recorded unusually high phosphate levels in the lake. But researchers needed to see it with their own eyes.
Last Chance Lake
The depth of Last Chance Lake is not more than 1 meter. Located on a volcanic plateau 1,000 meters (3,280 feet) above sea level in British Columbia, it contains the highest levels of concentrated phosphate ever recorded in any natural body of water on Earth.
Phosphate, a critical component of biological molecules, is a chemical compound containing the life-sustaining element phosphorus. It is found in molecules such as RNA and DNA, as well as ATP, a molecule necessary for energy production in all life forms. The abundance of phosphate in Last Chance Lake is 1,000 times greater than what is typical for oceans or lakes, according to Sebastian Haas, a postdoctoral researcher studying the microbiology and chemistry of aquatic environments at the University of Washington who led the paper.
Between 2021 and 2022, the team of researchers visited Last Chance Lake to collect and analyze water and sediment samples.
That’s when they discovered that Last Chance Lake was not only a home for phosphate, but also dolomite, a mineral that forms in response to the reaction between calcium, magnesium, and carbonate in the lake, allowing phosphorus to accumulate in this environment. Compound chemical processes influenced by minerals in the volcanic rock on which the lake formed and the arid climate effectively produced unique concentrations of phosphate; a set of conditions that researchers believe may have once led to the emergence of life. World according to Haas.
“We add credibility to the idea that this type of environment is plausible and suitable for the origin of life,” he said.
Last Chance Lake is not 4 billion years old; in fact, it is estimated to be less than 10,000 years old. This site is simply a modern analogue or natural snapshot of the past, ultimately offering scientists a chance to better understand what the primitive Earth looked like outside the laboratory.
“There is every reason to believe that similar lakes may have formed on early land about 4 billion years ago, because the volcanic rocks on which Last Chance Lake is located are essentially a prerequisite for the formation of soda lakes,” Haas said. “And what we’ve shown here, in part, is that soda lake water chemistry is a prerequisite for these high phosphate levels.”
Darwin’s warm little ponds
“Soda lakes,” such as Last Chance Lake, are shallow bodies of water filled with dissolved sodium and carbonate (just like baking soda), typically resulting from interactions between water and volcanic rocks. They can be found all over the world but are much less common than other bodies of salt water.
“These types of lakes have the highest levels of phosphate that match what (genetic molecules) people use to make in the laboratory,” Catling said.
When scientists attempted to replicate in the laboratory the chemical reactions that form biomolecules believed to be key to the origin of life, the phosphate concentrations required were a million times higher than normally found in the world’s natural bodies of water.
“If there were such lakes in the Ancient World, they would have been really high in phosphate, just like Last Chance Lake,” Catling added.
Bodies of water like this have long been on scientists’ radar as potential sources of primitive life. In the 1800s, Charles Darwin first wrote about the “warm little pond” theory, which suggested that warm, shallow, phosphate-rich lakes may have been where the first molecules of life formed.
“One of the things (Darwin) envisioned was bubbling pools like Yellowstone,” said Matthew Pasek, a professor at the University of South Florida who studies phosphorus chemistry and the origins of life sciences.
But that’s not the only popular theory about how life first emerged on Earth billions of years ago. Another is that life began in hydrothermal vents in the deep sea.
The new study adds to the body of evidence supporting the warm little pond hypothesis, said Pasek, who was not involved in the research.
“The whole point that you can have such high concentrations of phosphate in these ponds is definitely supported by this finding,” he said. “And it shows: ‘It could be like this.'”
But mass amounts of phosphate are not the only substance necessary for the origin of life. This list of prerequisites also includes sources of carbon and nitrogen, as well as the right chemical and physical elements that allow the formation of the necessary chemical compounds and reactions (including phenomena known as wet-dry cycles).
But the authors said they don’t claim that today’s Last Chance Lake has all the necessary ingredients for the building blocks of life, just a few critical pieces.
“Today’s Last Chance Lake does not contain many chemicals that we think are probably very important for the origin of life,” Haas said, citing cyanide as an example. Past studies suggest that a primitive version of the soda lake may well contain this substance.
Although the study “does not uniquely resolve the question of where life began,” according to Woodward Fischer, a geobiologist at the California Institute of Technology who was not involved in the research, it “highlights environments that scientists can see on Earth’s surface today.” Study in more detail to better understand the mechanics responsible for establishing life on our planet and potentially elsewhere.
Origin of life on Earth and beyond
If life did indeed arise in soda lakes on land rather than at the bottom of the ocean, this information could theoretically help search for evidence of life beyond Earth.
“If you think life started at the bottom of the ocean, you can take a closer look at the subglacial ocean on the moons of Saturn and Jupiter,” Haas said. “But if you think life arose on Earth’s land surfaces, planets like Mars may be much more important.”
The same type of rock formation that produces soda lakes can be found on much of the surface of rocky planets such as Mars; This suggests that life may have formed in a similar way elsewhere in the universe.
“Understanding how life arose on Earth is crucial to our search for life beyond Earth,” Haas told CNN. “Having a better understanding of how life arose on Earth provides information on where to look for life on other planets in the solar system or on moons of other planets.”
Ayurella Horn-Muller He has reported for Axios and Climate Central. His book, “Devourer of Devourer: The Extraordinary Story of the Kudzu Vine that Devoured the South,” will be released in the spring.
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