Charles Darwin proposed that life could have emerged in a “warm little pond” with the right cocktail of chemicals and energy. A study from the University of Washington, published this month in Communications Earth & Environment, reports that a shallow “soda lake” in western Canada shows promise for matching those requirements. The findings provide new support that life could have emerged from lakes on the early Earth, roughly 4 billion years ago.
Scientists have known that under the right conditions, the complex molecules of life can emerge spontaneously. As recently fictionalized in the blockbuster hit “Lessons in Chemistry,” biological molecules can be coaxed to form from inorganic molecules. In fact, long after the real-life 1950s-era discovery made amino acids, the building blocks of proteins, more recent work has made the building blocks of RNA. But this next step requires extremely high phosphate concentrations.
Phosphate forms the “backbone” of RNA and DNA and is also a key component of cell membranes. The concentrations of phosphate required to form these biomolecules in the lab are hundreds to 1 million times higher than the levels normally found in rivers, lakes or in the ocean. This has been called the “phosphate problem” for the emergence of life — a problem that soda lakes may have solved.
“I think these soda lakes provide an answer to the phosphate problem,” said senior author David Catling, a UW professor of Earth and space sciences. “Our answer is hopeful: This environment should occur on the early Earth, and probably on other planets, because it’s just a natural outcome of the way that planetary surfaces are made and how water chemistry works.”
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