The Ediacaran-Cambrian transition is one of the most fascinating periods in Earth’s history, as an evolutionary ‘arms race’ led to expanding animal diversity and the appearance of phyla that still exist today.
Chemical conditions in the oceans may have been radically different from those that exist today, and changes in the availability of oxygen, nutrients, and trace elements may all have played a role in pacing the expansion of ecological space and diversification of animal life
Recently, I’ve had the chance to work with colleagues at the Nanjing Institute of Geology and Paleontology, on a core that spans this critical period of change. Our results indicate that oxygenation of the oceans was a slow and stepwise process, and may not have been the key trigger that set the Cambrian Explosion in motion. The availability of trace metals (PDF), and their control of the nitrogen cycle (PDF), may instead have been key elements.