Lake in Canada may point to the origin of life on Earth

Imagine a completely arid world. Before you is a volcanic landscape, devoid of flora and fauna. Scattered throughout this gray and black expanse are shallow bodies of water. In each of these natural pools, a precise mixture of chemical substances and physical conditions is produced that could serve as a source of life on our planet.

Some scientists theorize that the scene may have been much like this, rather than an oceanic setting, when life emerged on Earth about 4 billion years ago. A study centered around a lake that exists today in the Canadian province of British Columbia offers new evidence supporting this idea.

The shallow, salty body of water nestled in volcanic rock – known as Last Chance Lake – holds clues that carbonate-rich lakes on ancient Earth could have been a “cradle of life,” according to study co-author David Catling, professor of geosciences at the University of Washington.

The discovery, published in the journal Nature on January 9, could advance scientific understanding of how life emerged.

“We were able to look for the specific conditions that people use to synthesize 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his colleagues became aware of the lake as a potential site for their research after a literature review uncovered an unpublished master's thesis from the 1990s that had recorded elevated phosphate levels there. But the researchers had to see for themselves.

Last Chance Lake

Last Chance Lake is no more than a foot deep. Located on a volcanic plateau in British Columbia, more than 1,000 meters above sea level, it contains the highest levels of concentrated phosphate ever recorded in any natural body of water on Earth.

A critical component of biological molecules, phosphate is a chemical compound that contains the vital element, phosphorus. It is found in molecules such as RNA and DNA, as well as in ATP, a molecule necessary for energy production in all forms of life.

The abundance of phosphate in Lake Last Chance is more than 1,000 times greater than the typical value 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 led the article.

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

They discovered that Last Chance Lake is not only a hotbed of phosphate, but also of the mineral dolomite, which allows phosphorus to accumulate in this environment and was formed in response to a reaction in the lake between calcium, magnesium and carbonate.

Composite chemical processes, influenced by the minerals in the volcanic rock upon which the lake formed, as well as an arid climate, produced the unique concentrations of phosphate – a set of conditions that researchers believe could have led to the emergence of life on Earth. , according to Haas.

“We are adding credibility to the idea that this type of environment would be favorable for the origin of life and it is plausible,” he said.

Last Chance Lake is not 4 billion years old – in fact, it is estimated to be less than 10,000 years old. The site is simply a modern analogue that ultimately offers scientists the opportunity to better understand what early Earth would have looked like outside of a laboratory.

“There is every reason to believe that similar lakes would have occurred on Earth about 4 billion years ago, because the volcanic rocks where Lake Last Chance is found are basically a prerequisite for the formation of soda lakes,” he said. Haas. “And what we are partially showing here is that the chemistry of the soda lake water is the prerequisite for these high phosphate levels.”

Darwin's small warm lakes

“Soda lakes,” like Last Chance Lake, are shallow bodies of water filled with dissolved sodium and carbonate — much like baking soda — that typically come from interactions between water and volcanic rocks.

They can be found all over the world, but are much less common than other saline bodies of water.

“These types of lakes have the highest levels of phosphate, which correspond to what people use in the laboratory to make genetic molecules,” Catling said.

When scientists have attempted to replicate in the laboratory the chemical reactions that form the biomolecules believed to be fundamental to the origin of life, the phosphate concentrations required are up to a million times greater than those typically found in the world's natural bodies of water.

“If you had these types of lakes on Earth back in the day, they would have been very rich in phosphate, just like Last Chance Lake,” Catling added.

Bodies of water like these have long been on scientists' radar as potential sources of primordial life. In the 1800s, Charles Darwin first wrote about his “warm little lake” theory, in which he proposed that warm, shallow, phosphate-rich lakes could have been where the first molecules of life formed.

“Part of what [Darwin] What you’re imagining are these bubbling pools… like Yellowstone,” said Matthew Pasek, a professor at the University of South Florida who studies the chemistry of phosphorus and the origins of life sciences.

But this isn't the only popular theory about how life first appeared on Earth billions of years ago. Another is that life began in hydrothermal vents on the sea floor.

The new study adds to the body of evidence supporting the small warm lake hypothesis, according to Pasek, who was not involved in the research.

“The bottom line, that it is possible to have such high concentrations of phosphate in these ponds, is definitely reinforced by this discovery,” he said. “And it shows, ‘This is how this can happen.'”

Still, abundant phosphate is 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 – including phenomena known as wet and dry cycles – that enable the formation of the necessary compounds and chemical reactions.

But the authors said they are not arguing that today's Last Chance Lake has all the components necessary to build life — just that it contains some of the critical pieces.

“Lake Last Chance currently does not contain several of the chemicals that we now think are likely crucial to the origin of life,” Haas said, citing cyanide as an example. Previous studies suggest that a primordial version of the soda lake may well have included the substance.

While this work “does not exclusively resolve the question of where life originated,” according to Woodward Fischer, a geobiologist at the California Institute of Technology who was not involved in the study, it “highlights environments on today's Earth's surface that scientists can study in more detail to better understand the mechanics responsible for the emergence of life on our planet and potentially elsewhere.”

The origin of life on Earth – and beyond

If life actually arose in soda lakes on Earth rather than at the bottom of the ocean, this knowledge could theoretically help in the search for evidence of life beyond Earth.

“If you think life originated on the ocean floor, you can take a closer look at the subglacial ocean on the moons of Saturn and Jupiter,” Haas said. “But if we think that life originated on the Earth’s surface, planets like Mars could become much more important.”

The same type of rock formation that produces soda lakes can be found across much of the surface of rocky planets like Mars – suggesting that life could form in a similar way elsewhere in the universe.

“Understanding how life originated on Earth is important to our search for life beyond Earth,” Haas told CNN . “Better understanding how life originated on Earth informs where to look for life on other planets, or on the moons of other planets, in the solar system.”