The origin of life on Earth required a supply of phosphorus for the synthesis of universal biomolecules. Closed lakes may have accumulated high concentrations of this element on early Earth. However, it is not clear whether prebiotic phosphorus uptake in such settings would then have been sustainable. New research by scientists from ETH Zurich, the University of Cambridge and the University of Science and Technology of China shows that large closed-basin lakes can combine high concentrations of phosphorus at steady state with extremely high rates of biological productivity.
Phosphorus is a critical element for all known forms of biochemistry, playing vital roles in metabolism, cell structure, and information-encoding polymers, e.g., DNA.
However, the environmental conditions that rendered phosphorus sufficiently available in aqueous solution to promote the chemical origins of life are uncertain.
“Large soda lakes without natural runoff could maintain phosphorus concentrations for a sufficiently long time, even if life begins to exist in them at some point — and continuously consumes phosphorus,” said Dr. Craig Walton, lead author of the study.
“Such lakes lose water only through evaporation. This means that phosphorus is left in the water instead of being washed away through rivers and streams.”
“As a result, very high concentrations of phosphorus can build up in these soda lakes.”
Not every soda lake is suitable; the researchers exclude small ones.
“As soon as life develops in them, their phosphorus supply would be depleted faster than it is replenished. This would nip in the bud both the chemical reactions and the developing life,” Dr. Walton said.
“In large soda lakes, on the other hand, the phosphorus concentrations are high enough to sustain both the basic chemical reactions and life over the long term.”
“These high concentrations are achieved through a high volume of inflowing river water, which contains phosphorus, while water only leaves the lake through evaporation.”
“Since phosphorus does not evaporate easily, it stays behind and accumulates in the lake.”
In their research, Dr. Walton and colleagues focused on Mono Lake in California, which has high phosphorus concentration at steady state despite extremely high rates of biological productivity.
“This is crucial because in small lakes, the phosphorus is used up before new amounts can be formed,” they said.
They consider large soda lakes that had a constant high phosphorus supply in the early history of the Earth to have been an ideal environment for the origin of life.
They assume that life is more likely to have originated in such large bodies of water than in small pools, as Charles Darwin had suspected.
The origin of life could therefore be closely linked to the special environment of large soda lakes, which, due to their geological setting and phosphorus balance, provided ideal conditions for prebiotic chemistry.
“This new theory helps to solve another piece of the puzzle of the origin of life on Earth,” Dr. Walton said.
A paper describing the findings was published in the journal Science Advances.
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Craig R. Walton et al. 2025. Large closed-basin lakes sustainably supplied phosphate during the origins of life. Science Advances 11 (8); doi: 10.1126/sciadv.adq0027
