The first life on Earth evolved in an atmosphere containing very little oxygen. Only later did oxygen become an essential element to many forms of life on Earth. Friedemann Freund’s work studies two closely related questions: how was the oxygen produced, and how actively did early life forms participate in the Earth’s “oxygen transition”? Traditionally, scientists have argued that oxygen became prevalent largely as the byproduct of photosynthesis. But Freund and microbiologist Lynn Rothschild of NASA suggest the mechanism may be much simpler: the weathering of rocks.
As collaborators in the SETI Institute’s NAI program, Freund investigates how oxygen may have been released through weathering, while Rothschild examines how microbes may have adapted to this oxygen. If their hypothesis is correct, we might expect oxygen to be prevalent in the atmospheres of many Earth-like planets, and not only those already bearing certain forms of life. The implications would be profound. If these scientists are right, we might expect complex life—perhaps even intelligence—to be much more prevalent in the universe than we would otherwise anticipate.
- SETI Institute Explorer, Special Edition 2005
Watch or listen to Dr. Freund's lecture on earthquake prediction, given at PARC on August 10, 2006