(By Kayleigh Schweiker ’22)
As scientific study regarding the mass extinction of marine life during the Cretaceous era has progressed, theories including extraterrestrial impact and intense volcanism have surfaced. However, a recent study co-authored by Ellen Thomas, Harold T. Stearns Professor of Integrative Sciences, suggests that carbon impact—not volcanism—was key in driving the Cretaceous mass extinction.
In a paper titled “Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact,” which was published in the Oct. 21 issue of the Proceedings of the National Academy of Sciences (PNAS), Thomas and her colleagues discuss how increases in ocean acidity played a driving force in the mass extinction of marine organisms. This mass extinction, labeled the “Crustaceous-Palogene die-off,” or the K-Pg event, led approximately 75% of plant and animal life on Earth to extinction. Though scientists have suggested that the presence of sulphuric acid proceeding the crash may have caused ocean pH levels to drop, Thomas and her team’s research on this topic reveals a different possibility.