Date: May 26, 2016
Source: University of Leeds
A study of more than 6,000 marine
fossils from the Antarctic shows that the mass extinction event that killed the
dinosaurs was sudden and just as deadly to life in the polar regions.
Previously, scientists had
thought that creatures living in the southernmost regions of the planet would
have been in a less perilous position during the mass extinction event than
those elsewhere on Earth.
The research, published today in
the journal Nature Communications, involved a six-year process of
identifying more than 6,000 marine fossils ranging in age 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.
This is one of the largest
collections of marine fossils of this age anywhere in the world. It includes a
wide range of species, from small snails and clams that lived on the sea floor,
to large and unusual creatures that swam in the surface waters of the ocean.
These include the ammonite Diplomoceras, a distant relative of modern squid and
octopus, with a paperclip-shaped shell that could grow as large as 2 metres,
and giant marine reptiles such as Mosasaurus, as featured in the film Jurassic
World.
With the marine fossils grouped
by age, the collection shows a dramatic 65-70% reduction in the number of
species living in the Antarctic 66 million years ago -- coinciding exactly with
the time when the dinosaurs and many other groups of organisms worldwide became
extinct at the end of the Cretaceous Period.
James Witts, a PhD student in the
University's School of Earth and Environment and lead author of the new
research paper said: "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. Clearly, a very sudden and catastrophic
event had occurred on Earth.
"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."
The study is the first to suggest
that the mass extinction event was just as rapid and severe in the polar
regions as elsewhere in the world.
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