Last Chance Lake: North America's “Soda Lake” could point to the origin of life on Earth

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Imagine a completely barren world. In front of you is a volcanic landscape devoid of plants and animals. Scattered throughout this gray and black expanse are shallow bodies of water. In each of these natural ponds a precise mixture of chemicals and physical conditions is prepared that can serve as the source of life in our bodies. planet.

Some scholars have hypothesized that the scene might look a lot like this, and not just a scene Ambient modewhen life first appeared on Earth approximately 4 billion years ago, and a Stady Centered around an existing lake in the Canadian province of British Columbia, it provides new support for this idea.

The shallow, salty body of water located on volcanic rock — known as Last Chance Lake — holds evidence that carbonate-rich lakes on ancient Earth could have been the “cradle of life,” according to study co-author David Catling, a professor at the University of Washington. Earth sciences. These findings, published in the journal Nature on January 9, could advance scientific understanding of the topic How life began.

“We were able to look for the specific conditions that people use to assemble the building blocks of life in nature,” Catling said. “We think we have a very promising place for the origin of life.”

Catling and his colleagues first realized the lake was a place to focus their research after a literature review revealed an unpublished master's thesis from the 1990s, which recorded unusually high levels of phosphate there. But the researchers had to see for themselves.

Last Chance Lake is only a foot deep. Located on a volcanic plateau in British Columbia more than 1,000 meters (3,280 ft) above sea level, it contains the highest levels of concentrated phosphate ever recorded in any natural body of water on Earth.

Phosphate is an important element in biological molecules, and it is a chemical compound that contains… Phosphorus, the element that sustains life. They are found in molecules such as RNA and DNA Beside Professional tennis playersIt is an essential molecule for energy production in all life forms. The abundance of phosphate in Last Chance Lake is more than 1,000 times greater What is typical For oceans or lakes, according to Sebastian Haas, a postdoctoral researcher who studies the microbiology and chemistry of aquatic environments at the University of Washington and who led the research.

Between 2021 and 2022, the research team visited Last Chance Lake to collect and analyze water and sediment samples.

That's when they discovered that Last Chance Lake is not only a hotbed of phosphate but also the mineral dolomite, which allows phosphorus to accumulate in this environment and may form in response to the reaction in the lake between calcium, magnesium and carbonate. Combined chemical processes, influenced by minerals from the volcanic rock on which the lake formed, combined with an arid climate, effectively produced unique concentrations of phosphate — a set of conditions that researchers believe could one day give rise to life on Earth. Earth, according to Haas.

“We add credence to the idea that this type of environment would be suitable for the origin of life, which is plausible,” he said.

Last Chance Lake is not only 4 billion years old, in fact, it is estimated to be less than 10,000 years old. The site is simply a modern counterpart, or a natural snapshot of the past that ultimately provides scientists with the opportunity to better understand what the primordial Earth looked like outside the laboratory.

“There is every reason to believe that similar lakes would have arisen on the first Earth about 4 billion years ago, because the volcanic rocks on which Last Chance Lake rests are essentially a prerequisite for the formation of soda lakes,” Haas said. “And what we're partly showing here is that the chemistry of the soda lake water is the prerequisite for these high phosphate levels.”

“Soda lakes” like Last Chance Lake are shallow bodies of water filled with dissolved sodium and carbonates — much like baking soda — that typically come from reactions between Water and volcanic rocks. They can be found all over the world but they do exist Much less common From other bodies of salt water.

“These types of lakes have the highest levels of phosphate that match what people use in the lab to make (genetic molecules),” Catling said.

When scientists in the laboratory tried to replicate the chemical reactions that make the biomolecules believed to exist The key to the origin of lifeThe necessary phosphate concentrations are up to a million times higher than what is normally found in the world's natural water bodies.

“If you had this type of lake on ancient Earth, it would be high in phosphate, just like Last Chance Lake,” Catling added.

Bodies of water like these have long been on scientists' radar as potential sources of primitive life. In the 19th century, Charles Darwin first wrote about his “Small warm pool“The theory that suggests that warm, shallow, phosphate-rich lakes could be the place where lakes are found The first molecules of life were formed.

“Part of what Darwin envisioned was that these effervescent pools… resembled… Yellowstonesaid Matthew Pasek, a professor at the University of South Florida who studies the chemistry of phosphorus and the origin of life sciences.

But this is not the only popular theory about how life first appeared on Earth billions of years ago. Another thing 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 hypothesisAccording to Pasek, who was not involved in the research.

“The main point, which is that you can get such high concentrations of phosphate in these ponds, is certainly reinforced by this result,” he said. “It shows that this is how it can happen.”

However, phosphate in large quantities is not the only substance needed for life to arise. The list of basic requirements also includes sources of carbon and nitrogen, as well as the correct chemical and physical elements, including phenomena known as Wet dry cycles – Which allows the formation of the necessary compounds and chemical reactions.

But the authors said they do not confirm that the Last Chance Lake that exists today contains all the ingredients necessary for the building blocks of life, but only a few important pieces.

“Lake of Last Chance at present does not contain many of the chemicals that we now think may be crucial to the origin of life,” Haas said, citing cyanide as one example. Previous studies It suggests that a primitive version of a soda lake may have contained the substance.

While this work “does not uniquely resolve the question of where life originated,” according to Woodward Fisher, a geobiologist at Caltech who was not involved in the study, it “sheds light on environments on Earth today that scientists can explore.” “. Study in more detail to better understand the mechanisms responsible for creating life on our planet and perhaps elsewhere.

The origin of life on Earth – and beyond

If life actually appears in soda lakes on Earth, rather than on the ocean floor, this knowledge could theoretically help Searching for evidence of life Beyond Earth.

“If you think life originated at the bottom of the ocean, maybe you should take a closer look at the world Subglacial ocean “On the moons of Saturn and Jupiter,” Haas said. “But if you believe that life arose on Earth, then planets like Mars may be much more important.”

The same kind of Rock formation Soda lakes that produce can be found over much of the Earth's surface Rocky planets such as Mars – Which indicates that life may have formed in… In a similar way Somewhere else in the universe.

“Understanding how life arose on Earth is of such importance to our search for life beyond Earth,” Haas told CNN. “Getting a better understanding of how life arose on Earth tells us where to look for life on other planets, or moons of other planets, in the solar system.”

Aurella Horn Müller Axios and Climate Central reported. Her book, “The Devourer: The Extraordinary Story of Kudzu, the Vine That Ate the South,” is scheduled to be published in the spring.