Lidya Tarhan, a post-doc in the Briggs lab at Yale, is first author of a new paper published in Nature Geoscience – Protracted Development of bioturbation through the early Plaeozoic Era. This work from Lidya, members of the Briggs Lab, and collaborators, indicates that marine animals took significantly longer than previously thought to commence major bioturbation (burrowing and mixing) of marine surface sediments. Rather than the Cambrian (541 Ma) as previously thought, they propose that this happened much later during the Silurian (~420 Ma). This has potentially broad implications sulfate and oxygen levels in the oceans during this time, for the our understanding of Earth’s ancient ecosystems.
Here is a link to a news story titled ‘Ancient dirt churners took their time stirring up the ocean floor’