Zoe’s weekly roundup of news, trends and issues affecting our environment and our planet’s future
By Geoff Grant – Zoe Environmental Editor
Zoe is the Greek word for “life,” and to that we dedicate this installment of This Week in Green. As in NASA researchers discover a new life form on Earth; an Italian lingerie maker gives a second life to old bras; the Pope may bring renewed life to solar-powered cars.
Not Men from Mars, but New Life Form on Earth
Mono Lake in California
In a landmark finding that may redefine “life” as we know it, NASA announced the discovery of a new life form on Earth: a microbe that lives and reproduces on arsenic.
“It’s terrestrial life – but not life as we know it,” said Mary Voytek, director of NASA’s astrobiology program.
The micro-organism, or bacterium, is from the bottom of Mono Lake in California, and was essentially created in laboratory testing by astrobiology researchers funded by NASA. The discovery disproves the long-held premise that all life on Earth is based on six building blocks: carbon, hydrogen, nitrogen, oxygen, phosphorous and sulfur. This bacterium exists on arsenic instead of phosphorus.
“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.”
“We cracked open the door for what’s possible for life elsewhere in the universe. That’s profound for understanding how life is formed, and where life is found,” said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team’s lead scientist. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?”
The researchers discovered through laboratory testing that the micro-organism uses arsenic instead of phosphorus in its cell components. Phosphorus composes the core of DNA and RNA that give us genetics and is considered essential to all living cells.
“Every living thing uses phosphorous to build its DNA,” said James Elser, a professor at Arizona State University, during a NASA press conference. “The idea that I’m sitting here today discussing the possibility that it’s not true, it’s shocking.”
The ramifications of NASA’s announcement will cut across a broad range of disciplines, including biology, microbiology, organic chemistry, the Earth’s evolution, the study of diseases, and the search for life on other planets.
“The idea of alternative biochemistries for life is common in science fiction,” said Carl Pilcher, director of the NASA Astrobiology Institute. “Until now a life form using arsenic as a building block was only theoretical, but now we know such life exists in Mono Lake.”