Life could have emerged from lakes abundant with phosphorous, which forms the backbone of DNA and RNA molecules, according to a new study conducted by scientists from the University of Washington. Researchers knew long ago that life requires phosphorous, however the chemical element is scarce. For 50 years, what's called "the phosphate problem, has plagued studies on the origin of life", said lead author Jonathan Toner, a University of Washington research assistant professor of Earth and space sciences.
The study focused on carbonate-rich lakes, which form in dry environments within depressions that funnel water draining from surrounding landscape, researchers said. They first looked at levels of phosphorous in existing lakes, including Mono in California, Magadi in Kenya, and Lonar Lake in India. They found that these lakes have very high concentrations of phosphorous leading them to believe that there is some mechanism that creates the abundance of this chemical element.
Scientists then conducted lab experiments with carbonate-rich water using different chemical composition. They showed that in most lakes, calcium, which is abundant on Earth binds with phosphorous, but in carbonate-rich waters, the carbonate eclipses phosphate and binds with calcium, leaving some of the phosphate freely available in water.
"It's a straightforward idea, which is its appeal. It solves the phosphate problem in an elegant and plausible way”, said Jonathan Toner.