Life as we know it requires phosphorus. It’s one of the six main chemical elements of life, it forms the backbone of DNA and RNA molecules, acts as the main currency for energy in all cells and anchors the lipids that separate cells from their surrounding environment.
But how did a lifeless environment on the early Earth supply this key ingredient?
“For 50 years, what’s called ‘the phosphate problem,’ has plagued studies on the origin of life,” said first author Jonathan Toner, a University of Washington research assistant professor of Earth and space sciences.
The problem is that chemical reactions that make the building blocks of living things need a lot of phosphorus, but phosphorus is scarce. A new UW study, published Dec. 30 in the Proceedings of the National Academy of Sciences, finds an answer to this problem in certain types of lakes.
The study focuses on carbonate-rich lakes, 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 extremely high phosphate levels in these lakes and ponds would have driven reactions that put phosphorus into the molecular building blocks of RNA, proteins, and fats, all of which were needed to get life going,” said co-author David Catling, a UW professor of Earth & space sciences.
Read more at UW News »