66 million years ago a mass extinction event, believed to be caused by a massive asteroid impact or volcanic explosions, wiped dinosaurs from the face of the planet. For years scientists have believed that as the animals at the poles were far enough from harm and hardy enough to survive changes in their climate. But a study of over 6,000 Antarctic marine fossils from the period shows that as the dinosaurs perished, polar life also took a massive hit.
There's a certain logic to previous assumptions that Antarctica would have fared relatively well during the mass extinction; species that survive in the region are accustomed to a highly seasonal climate, irregular food supply and manage to live in darkness for half the year.
But a massive trove of marine fossils, ranging from 69- to 65-million-years-old that were excavated by scientists from the University of Leeds and the British Antarctic Survey on Seymour Island in the Antarctic Peninsula, show that Antarctic life was the victim of a very sudden, massive, and devastating event.
Researchers have spent six years identifying the fossils, which range from small snails and clams to the 58-foot-long Mosasaurus lizard, and grouped them by age. What they found was that 66-million-years ago there was a 65-70% reduction in the number of species living in the Antarctic, at exactly the same time as the mass extinction event was rocking other regions of the Earth.
As James Witts, a PhD student at the University of Leed's School of Earth and Environment explains:
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.
And the reason for this sudden Antarctic extinction ties into, and may provide clarification, for existing mass extinction theories for the period:
This is the strongest evidence from fossils that the main driver of this extinction event was the after-effects of a huge asteroid impact, rather than a slower decline caused by natural changes to the climate or by severe volcanism stressing global environments
Indeed, these marine fossils may provide some of the most accurate information about the mass extinction event yet, as they are far more abundant and of far better quality than dinosaur fossils.
Lead Image Credit: James McKay