Key Hurdle To Life Was Lower On Mars

Phosphate is found in DNA, RNA, and the energy-storage molecule ATP, making it crucial for life’s existence on Earth. If life ever occurred on Mars, whatever creatures dwelled there also probably needed phosphate. On both planets, the inorganic anion comes mainly from dissolving phosphate-containing minerals. Christopher T. Adcock and coworkers at the University of Nevada, Las Vegas, have now determined that the phosphate hurdle to forming life was likely lower on Mars, because martian minerals release more phosphate than Earth’s do (Nat. Geosci. 2013, DOI: 10.1038/ngeo1923). The researchers obtained a sample of fluorapatite, the dominant phosphate mineral on Earth, and synthesized two phosphate minerals common on Mars. They then measured the minerals’ phosphate release rates in water of various pH levels. The synthesized martian minerals released two times as much phosphate and did so at up to five times the rate of fluorapatite.