NASA has discovered a new life form that can grow by substituting arsenic for phosphorus, redefining the agency's search for different life forms other than the ones known on earth.
The discovery was made by astrobiologists who performed tests by taking mud from Mono Lake -- a body of water in Northern California three times as salty as the ocean -- which has high arsenic content, said Felisa Wolfe-Simon, a NASA astrobiology research fellow with the U.S. Geological Survey, during a press conference Thursday.
Researchers created an environment that had everything else a typical life form that exists on earth would need to survive, except for phosphorus - which is one of the building blocks of all existing life forms. Instead, they used arsenic -- normally a toxic element to existing life forms -- to replace phosphorus, she said.
To their surprise, a microbe not only was able to tolerate the toxicity, "but it grew and thrived," Wolfe-Simon said. "Nothing should have grown."
The experiment has widespread ramifications for how NASA will search for other signs of life, she said.
"We've cracked open the door for what's possible with life elsewhere in the universe," Wolfe-Simon said. "What else might we find? What else might we want to look for?"
The discovery also could have an effect on other kinds of more practical research here on earth, said James Elser, a professor at Arizona State University.
Showing great enthusiasm for the discovery, Elser said the finding completely upends one of the fundamental principles he teaches his students -- that "every living thing uses phosphorus to build its DNA."
Calling the finding "unbelievable," he said that it has many applications for researchers working with processes that use phosphorus today, such as wastewater treatment and bio-energy production.
Not every researcher during the press conference was so enthusiastic about the finding, however.
Steven Benner, distinguished fellow for the Foundation for Applied Molecular Evolution -- who admittedly said he was on hand to dampen the fervor over the discovery -- called it "an exceptional result" that needs "exceptional evidence to support it. We nonetheless find it interesting," he said.
Nevertheless, the finding does pave the way for new areas of exploration for NASA, and could win the agency more funding for new missions to Mars and other planets in search of life forms, observers said.