Washington: The early Earth may have hosted many carbonate-rich lakes, which contained high enough phosphorus concentrations to get life started on our planet, according to a study. Phosphorus is one of the six main chemical elements of life, and forms the backbone of DNA and RNA molecules. The element acts as the main currency for energy in all cells and anchors the lipids that separate cells from their surrounding environment.
"For 50 years, what's called 'the phosphate problem,' has plagued studies on the origin of life," said Jonathan Toner, an assistant professor at the University of Washington (UW) in the US. The problem is that chemical reactions that make the building blocks of living things need a lot of phosphorus, but the element is scarce. The new study, published in the journal Proceedings of the National Academy of Sciences, has found an answer to this problem in certain types of lakes.
The research focused on lakes rich in carbonate -- a salt of carbonic acid -- which form in dry environments within depressions that funnel water draining from the surrounding landscape.
Because of high evaporation rates, the lake waters concentrate into salty and alkaline, or high-pH, solutions. Such lakes, also known as alkaline or soda lakes, are found on all seven continents, the researchers said.
They first looked at phosphorus measurements in existing carbonate-rich lakes, including Mono Lake in California, US, Lake Magadi in Kenya and Lonar Lake in India.
While the exact concentration depends on where the samples were taken and during what season, the researchers found that carbonate-rich lakes have up to 50,000 times phosphorus levels found in seawater, rivers and other types of lakes.
Such high concentrations point to the existence of some common, natural mechanism that accumulates phosphorus in these lakes, the researchers said.
Today these carbonate-rich lakes are biologically rich and support life ranging from microbes to Lake Magadi's famous flocks of flamingoes, they said.
The researchers carried lab experiments with bottles of carbonate-rich water at different chemical compositions to understand how the lakes accumulate phosphorus, and how high phosphorus concentrations could get in a lifeless environment.
- PTI
