Theoretical origin of life: finding phosphates (Introduction)

by David Turell , Friday, February 28, 2025, 17:32 (33 days ago) @ David Turell

Another vital element for life:

https://www.sciencemagazinedigital.org/sciencemagazine/library/item/28_february_2025/42...

"Be they microbes or monkeys, organisms require phosphorus—and lots of it. It’s a key component of DNA and RNA, of the ATP that fuels living cells, and of the lipids that make up cell membranes. The element’s centrality has long puzzled researchers trying to understand early life, because phosphorus isn’t naturally abundant in most watery environments, the kind of place where life probably began. Now, a trio of new papers supports a recent proposal that volcanic activity around highly alkaline “soda“ lakes—and perhaps hot springs—could have enabled phosphorus compounds to accumulate to levels needed for life to start and spread.

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"...although the new papers offer a plausible route to solving what has long been known as the “phosphorus problem,” researchers still need to show that compounds generated under these conditions actually undergo reactions resembling rudimentary biochemistry. Geochemist Matthew Pasek of Rensselaer Polytechnic Institute agrees, but adds: “I think we are much further along than we were before.”

"The recognition that phosphorus availability was a likely bottleneck on the road to life dates as far back as 1955, to a paper by American biochemist Addison Gulick. The origin of life would probably have required high concentrations of compounds such as phosphate—a phosphorus atom surrounded by four oxygens. In oceans, rivers, and most lakes the phosphate concentration is typically 10,000 times too low.

"Early Earth was different, though. Phosphorus is present in volcanic lavas, and the young planet had a lot more volcanic activity than today. In a series of lab studies reported in September 2024 in Communications Earth & Environment, Pasek and his colleagues found that reactions between iron-rich volcanic rocks and water at high temperatures— like those found in a hot spring, or hydrothermal, environment on land—convert phosphorus to a range of different phosphates. If the hot spring periodically dried up, it might concentrate phosphates enough to promote vital biochemical reactions.

"Soda lakes are another place that could happen, as University of Washington earth scientists David Catling and Jonathan Toner first proposed in the Proceedings of the National Academy of Sciences in 2020. Such lakes also form in volcanic environments, in closed basins filled by runoff that has weathered sodium and carbonate—the ingredients of baking soda—out of volcanic rocks. With no outflow, the lakes lose water only to evaporation, which concentrates the chemicals over time.

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“'This is a major barrier,” says Craig Walton of the University of Cambridge. He and his colleagues recently analyzed much larger soda lakes, including Mono Lake in California, which is 21 kilometers long and up to 17 meters deep. Phosphate levels there are far higher than in nonsoda lakes, the researchers reported last week in Science Advances, although they don’t rival the phosphate concentrations in the British Columbia ponds. But Mono and its peers offer a much more stable supply. “These large-scale lakes give you a bit of both,” Walton says.

"To him, the combination of volcanic activity and soda lakes is “pretty close to a geological solution” to the phosphorus problem. Pasek thinks hydrothermal pools probably played a role, too. “There is room for both,” he says. But with any proposal about how life began billions of years ago, Preiner advises humility. “There’s uncertainty here that we just have to live with.'”

Comment: this finding drives us to the conclusion that hydrothermal vents in the ocean floor would have provided phosphorous for the origin of life. Only oceans provided a continuous environment for any life forms that might appear.