Dinosaur extinction event took out polar creatures, too

LEEDS, England, May 26 (UPI) -- Whether caused by asteroid or volcanism -- or both -- scientists now know few places on Earth offered safety from the extinction event that killed the dinosaurs.

An extensive survey of ancient marine fossils from the Antarctic Peninsula proves the ecosystems to the south suffered considerably during the Cretaceous-Paleogene extinction event.

The survey included 6,000 marine fossils dated to between 69 million and 65 million years old. A wide range of species and sizes were included -- from sea snails to large marine reptiles. The analysis suggests biodiversity and abundance were reduced by 65 to 70 percent.

"Our research essentially shows that one day everything was fine -- the Antarctic had a thriving and diverse marine community -- and the next, it wasn't," James Witts, a PhD student in Earth and environmental sciences at the University of Leeds, said in a news release. "Clearly, a very sudden and catastrophic event had occurred on Earth."

Researchers have previously hypothesized that animals living near the poles were better adapted to the rapid change as a result of their habitat's seasonal variability. Scientists have also argued polar ecosystems were far enough away from the catastrophe to escape serious harm. The latest findings, published in the journal Nature Communications, belie such theories.

"These Antarctic rocks contain a truly exceptional assemblage of fossils that have yielded new and surprising information about the evolution of life 66 million years ago," added study co-author Jane Francis, a researcher with the British Antarctic Survey. "Even the animals that lived at the ends of the Earth close to the South Pole were not safe from the devastating effects of the mass extinction at the end of the Cretaceous Period."

Researchers say marine environments are especially conducive to fossil preservation, and thus can provide a much more accurate representation of environmental and ecological change.