Photosynthesis without oxygen
Microbes learn to run on sunlight — but split hydrogen sulfide rather than water, so nothing is released.
- When
- Known to
- ± 200 million years
- Era
- Paleoarchean, Archean
Long before cyanobacteria, purple and green sulfur bacteria develop photosynthesis that uses sunlight to fix carbon while oxidising hydrogen sulfide or dissolved iron instead of water. No oxygen is produced. It is the more accessible chemistry, needing far less energy than splitting water, and its machinery is the direct ancestor of the system that later oxygenates the planet.