New Study Reveals What Really Caused Dinosaurs to Go Extinct
A new study has finally revealed what caused dinosaurs to go extinct. While scientists long ago established that the species was eradicated some 66 million years ago by a city-sized asteroid, the exact details of how 75 percent of Earth's species died off was still unknown. However, the assumption was that it might have been due to the extreme cold caused by the event.
The report, published Monday in the journal Nature Geoscience, posits that a fine dust made from pulverized rock, launched into Earth's atmosphere in the wake of the asteroid's impact, may have actually played a greater part in the extinction than the asteroid itself. The dust blocked out the sun so severely it left plants unable to photosynthesize for nearly 2 years. Photosynthesis, in which plants use sunlight, water and carbon dioxide to produce energy and oxygen, is critical to life on Earth.
“Photosynthesis shutting down for almost two years after impact caused severe challenges (for life),” lead study author and planetary scientist Cem Berk Senel told CNN. “It collapsed the food web, creating a chain reaction of extinctions.”
“Within a few weeks, months (of the impact), the planet underwent a global shutdown in photosynthesis, which continued for almost two years during which photosynthesis is completely gone,” Senel explained. “Then it starts getting back to recovery after these two years. Within three to four years, it reaches a complete recovery.”
In order to obtain their results, Senel and their team created a new computer model which simulated the global climate in the aftermath of the impact. They based this off of available information regarding the climate at that time, as well as new data taken from settlement samples at North Dakota’s Tanis fossil sight.
The new samples taken for the current study showed that the presence of silicate dust particles remained in the atmosphere for up to 15 years after the asteroid hit, and that the impact may have cooled the global climate by as much as 59°F.
Paleontologist Alfio Alessandro Chiarenza, a postdoctoral researcher who was not involved with the study, told CNN that the findings shed light on the previously mysterious mass extinction. “It provides more precise constraints on the composition, properties, and duration of the fine dust component ejected from the impact site, which contributed to the global darkness during the impact winter,” he said.
“This new information enables us to investigate the processes and duration more rigorously, shedding light on the mechanisms behind the blockage of solar radiation, resulting in photosynthesis shutdown and a significant drop in temperatures below the habitable conditions for example for non-avian dinosaurs,” Chiarenza concluded.