Oxygen pulses through the Cambrian ocean
Surges of oxygen coincide, again and again, with surges of animal diversity.
- When
- Known to
- ± 3 million years
- Era
- Cambrian, Paleozoic
Geochemical records show repeated oxygenation episodes through the early Cambrian, notably between 521 and 519 million years ago. Each coincides with expansions in reef size, body size and ecological complexity. Larger, more active animals — especially predators — need far more oxygen than microbial life, so the correlation is probably causal, though whether oxygen enabled the animals or the animals altered the oxygen remains argued.