Department of Earth and Environmental Sciences News
Winguths publish paper examining timing of events during largest extinction in geological record
Two geoscientists at The University of Texas at Arlington are co-authors of a study which used multiple forms of analysis to provide new insights into the largest mass extinction in the geological record, the end-Permian extinction (EPE).
The EPE, also called “The Great Dying”, occurred near the Permian-Triassic boundary about 252 million years ago when the supercontinent Pangea existed, and encompassed an extinction of up to 96 percent of marine species and up to 70 percent of land vertebrate species. The new study revealed that land-based ecosystems underwent a massive collapse centuries before the event’s effects were felt in the oceans.
Arne Winguth, associate professor and chair of the UTA Department of Earth and Environmental Sciences, and Cornelia Winguth, EES assistant professor of instruction, contributed to the paper, which appeared in the January 23 edition of the scientific journal Nature Communications. The study, titled “Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis,” included researchers from the University of Nebraska-Lincoln and Monash University in Melbourne, Australia.
Mitali Gautam, a UTA graduate student, assisted in the analysis of climate modeling and in preparation of graphics for the paper. The scientists carried out climate simulations with the community climate system model from the U.S. National Center for Atmospheric Research (NCAR) in Boulder, Colorado, using one of the world’s fastest supercomputers, located in Cheyenne, Wyoming.
The terrestrial extinction event at the Permian-Triassic boundary is associated with an expansion of subtropical arid belts. A “perfect storm” of natural catastrophes combined to wipe out nearly all life on Earth.
“Our research shows a link between the terrestrial mass extinction and the massive release of carbon dioxide from volcanism in the Siberian Traps, a large region of volcanic deposits in the area now known as Siberia,” Winguth said. “This release of greenhouse gases led to a transition into an extreme hothouse climate, causing a decline in terrestrial ecosystems, as well as deoxynation and rapid acidification of the oceans. Depletion of the ozone layer may have followed by the release of hydrogen sulfide from the ocean into the atmosphere which in turn could have affected the terrestrial extinction.”
The Siberian Traps eruptions – one of the largest volcanic events in Earth’s history – continued for nearly 2 million years and spanned the Permian-Triassic boundary. Acidification is an ongoing decrease in the pH of the Earth's oceans, caused by the increase of carbon dioxide (CO2) from the atmosphere.
“Our role at UTA in this study was to look at different climate information and assess how seasonality changed,” Arne Winguth said. “We assessed the climate-sensitivity to different CO2levels, and compared the modeling data with the fossil record. What is unique about this study is that we utilized a wide range of methods including high-precision radiometric dating, stratigraphic analysis, selected macro fossils, and modeling together and combined the results into a single, cohesive timeline.”
For this study, well core stratigraphic sections and fossils were taken from the Sydney Basin, New South Wales, indicating that the collapse of land-based life forms happened roughly 370 years before the main marine extinction event.
Samples from the Sydney Basin were used because geochronological constraints there are of much better quality and are much more stratigraphically complete than those found in other continental basins, the authors explain in the paper. The Sydney Basin preserves a thick sedimentary succession exposed in coastal cliffs around Sydney. There is broad consensus that a major crisis in terrestrial ecosystems happened around the end of the Permian.
The oceans initially would have been safe from the cataclysmic events taking place on land, but eventually the massive increase in CO2 would have led to rising marine temperatures and a stagnation of oceanic circulation.
“This cascading extinction event, initiating on land and eventually killing off the majority of life in the oceans, makes a sorry tale,” said Chris Fielding, professor of earth and atmospheric sciences at the University of Nebraska-Lincoln and a co-author of the study.
Added Winguth, “I think we can learn lessons regarding future climate change by examining events from the past such as this one.”
The project involves global environmental impact and data driven discovery, two of the main pillars of UTA’s Strategic Plan 2020: Bold Solutions | Global Impact.