The rise of algae
Green and red algae displace bacteria at the base of the food chain, and the ocean's energy supply transforms.
- When
- Known to
- ± 50 million years
- Era
- Neoproterozoic, Proterozoic
Algal steranes appear and then surge in the biomarker record between about 780 and 650 million years ago, marking the point where eukaryotic algae overtake cyanobacteria as primary producers. Algae are far larger and more nutritious than bacteria, so the food chains they support can be longer and can carry bigger organisms. A shift in the marine phosphorus cycle appears to have driven it, and predatory eukaryotes proliferate in response.