Smith Lecture: Testing UV-B Radiation as a Proposed Driver of the End-Permian Biotic Crisis
Cindy Looy, Berkeley
The ozone layer plays a vital role in intercepting harmful solar ultraviolet-B radiation (UV-B) from reaching Earth’s surface. However, its effectiveness in doing so has fluctuated in the past and little is known of the impacts of a thinning ozone layer on vegetation. Anticipating potential consequences in the future depends on understanding time intervals with heightened UV stress in the past. The largest mass extinction in history at the end of the Permian Period (~252 million years ago) may have been one of these time intervals. Plant fossil records from this crisis show two odd features worldwide. Many pollen grains produced by vanishing woodland seed plants were malformed, and lycopsids spread their spores frequently as unseparated clusters of four. Heightened UV-B exposure was hypothesized to have caused these abnormalities. Compounds produced by the largest volcanic province in history, the Siberian Traps, likely caused prolonged or frequent deterioration of the ozone shield. Using the results of UV-B radiation experiments I will show that the collapse of the ozone layer could explain the abnormalities and extinction patterns in plants observed during the end-Permian biotic crisis.
Explore Similar Events
Loading Similar Events...