Advance notice of the NASA press conference today about the discovery of a terrestrial bacteria with arsenic in place of phosphorus [right, credit AAAS] set off worldwide speculation, rumors, and wild stories about alien life. The actual results are coming out in tomorrow's online issue of Science Express, in a paper co-authored by ASU researchers Ariel Anbar, Paul Davies, and Gwyneth Gordon. They found a bacterium in Mono Lake that can incorporate arsenic in place of phosphorus into its DNA. As I read this, all known life on Earth depends on 6 key elements - carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus. We've never seen life that is based on something else. The discovery opens the possibility of a much broader range of life forms across the universe.
Read the post at Knight Science Journalism Tracker to get a sense of how the feeding frenzy grew as bloggers, tabloid reporters, and even the mainstream press scrambled to embellish speculation.
Expect to see the late night jokes come pretty quickly: Arsenic life forms are okay but would you want one to marry into the family? Will candidates for president have to offer DNA tests along with birth certificates to prove not only are they American but also human? What happens if the bacteria are declared an endangered species - do we fill lakes with arsenic for them?
Ref: “A bacterium that can grow by using arsenic instead of phosphorus,” Science DOI: 10.1126/science.1197258