A tectonically driven Ediacaran oxygenation event.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31217418.
- Also identified by DOI 10.1038/s41467-019-10286-x and PMC identifier 6584537.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The diversification of complex animal life during the Cambrian Period (541-485.4 Ma) is thought to have been contingent on an oxygenation event sometime during ~850 to 541 Ma in the Neoproterozoic Era. Whilst abundant geochemical evidence indicates repeated intervals of ocean oxygenation during this time, the timing and magnitude of any changes in atmospheric pO<sub>2</sub> remain uncertain. Recent work indicates a large increase in the tectonic CO<sub>2</sub> degassing rate between the Neoproterozoic and Paleozoic Eras. We use a biogeochemical model to show that this increase in the total carbon and sulphur throughput of the Earth system increased the rate of organic carbon and pyrite sulphur burial and hence atmospheric pO<sub>2</sub>. Modelled atmospheric pO<sub>2</sub> increases by ~50% during the Ediacaran Period (635-541 Ma), reaching ~0.25 of the present atmospheric level (PAL), broadly consistent with the estimated pO<sub>2</sub> > 0.1-0.25 PAL requirement of large, mobile and predatory animals during the Cambrian explosion.