Johns Hopkins University Scientists Uncover Surprising Key Player in Evolutionary History

Recent research conducted by Johns Hopkins University has shed light on the significant role prehistoric worms played in increasing oxygen levels through their burrowing activities. This discovery has been linked to the Great Ordovician Biodiversification Event, a period around 480 million years ago when a vast array of new species emerged.

According to the study published in the journal Geochimica et Cosmochimica Acta, the digging and burrowing of these ancient worms and other invertebrates on ocean floors led to the release of oxygen into the atmosphere and oceans. This process kick-started the Great Ordovician Biodiversification Event, marking a crucial stage in the evolutionary history of life on Earth.

Senior author Maya Gomes, an assistant professor in the Department of Earth and Planetary Sciences, expressed astonishment at how such small creatures could have such a profound impact on the course of evolution. The research team updated models to better understand the relationship between sediment mixing, pyrite formation, and oxygen levels over millions of years.

By studying pyrite levels in sediment samples from various sites along the Chesapeake Bay shoreline in Maryland, the researchers found that even minimal sediment mixing led to a significant increase in pyrite formation. This challenges previous beliefs that sediment mixing could hinder oxygen buildup and suggests a delicate balance is needed for oxygen levels to rise.

The new findings indicate that the rise in oxygen levels during the Paleozoic era, particularly the Ordovician period, likely facilitated the rapid diversification of species during the Great Ordovician Biodiversification Event. This research provides valuable insights into the interplay between oxygen levels and evolutionary events in Earth’s history.

The study, titled “Trends in estuarine pyrite formation point to an alternative model for Paleozoic pyrite burial,” was authored by Kalev Hantsoo, Maya Gomes, Dana Brenner, Jeffrey Cornwell, Cindy M. Palinkas, and Sairah Malkin, and was published on April 16, 2024, in Geochimica et Cosmochimica Acta. The research was supported by the American Chemical Society Petroleum Research Fund.