Antarctic fossils reveal creatures weren't safer in the south

Antarctic fossils reveal creatures weren’t safer in the south

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 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 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 , 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 as elsewhere in the world.

Previously, scientists had thought that organisms living near the Poles were far enough away from the cause of the extinction to be badly affected – whether this was an asteroid impact in the Gulf of Mexico, where a giant buried impact crater is found today, or extreme volcanism in the Deccan volcanic province in India.

Furthermore, it had been proposed that animals and plants in the polar regions would have been more resilient to global climatic changes associated with an asteroid impact as a result of living in environments that were always strongly seasonal. For example, life near the Poles has to adapt to living in darkness for half of the year and to an irregular food supply.

Professor Jane Francis from the British Antarctic Survey, a co-author of the study, said: "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. 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 at the end of the Cretaceous Period."

While some previous studies have suggested that the demise of the dinosaurs and other groups was gradual, many scientists argue that the dinosaur fossil record in particular is patchy, and cannot compete with marine fossils in terms of quantity and biodiversity.

James Witts said: "Most fossils are formed in marine environments, where it is easy for sediment to accumulate rapidly and bury parts of animals, such as bones, or bodies of creatures with a hard shell. For a dinosaur or other land animal to become fossilised, a series of favourable events are needed, such as for bones to fall into stagnant water and be buried rapidly to prevent decomposition, or be washed out to sea by rivers.

"This means that marine fossils are generally much more abundant. They can give us a much larger data set for studying how ecosystems and biodiversity change over time in the geological past, and enable us to draw robust conclusions about events during periods of rapid environmental change, like mass extinctions."


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More information: James D. Witts et al. Macrofossil evidence for a rapid and severe Cretaceous–Paleogene mass extinction in Antarctica, Nature Communications (2016). DOI: 10.1038/NCOMMS11738
Journal information: Nature Communications

Citation: Antarctic fossils reveal creatures weren't safer in the south (2016, May 26) retrieved 19 October 2019 from https://phys.org/news/2016-05-antarctic-fossils-reveal-creatures-werent.html
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May 26, 2016
Will there be any place to live after we ruin most of the Earth?

The Deniers will blame Hillary.

May 26, 2016
The Pathological Liar, who burned 150 dollars in gasoline every month, will not blame himself.

BTW. When caught in his lies, he blamed his wife for burning all that gas and then boasted that his lies cannot hurt him.

May 26, 2016
Thank you for the demonstration of your character. But our main car is an Electric Vehicle now, and we make our own electricity from the Sun.

Those who drive stinking Diesels will ruin the Earth for the rest of us, and there will be no place to go.

May 27, 2016
I've been wiping my ass with an ancient history book!

I prefer the one by the Brothers Grimm.

May 28, 2016
This seems to clinch it: "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 image containing the age model, which isn't paywalled, indicates the extinction happens within a million year, and looks more like 100 000 yars tops. IIRC the Deccan traps starts 10 Myrs before the K/Pg boundary.

May 28, 2016
@BartV: Historians say it isn't one of their books but a collection of religious myths. The root is the Dead Sea Scrolls, who show that it was pulled together and developed from diverse oral myths, oh, about 66 Myrs after these events.

Besides, if you actually read it as those who leave these superstitions behind, it is painfully obvious it can't be used to tell facts. It starts out with two differing 'histories' describing the same mythical periods. In effect the text collection tells the reader *on the first two pages* "I am lying to you." And most people stop reading there, because what would be the point?

Superstition, magic religious myth, text collection, oral based from many religions at much later times than the periods they fantasize about so non-historical, obvious lie, ... Religion is a lot of things but should never be confused with the real world and its facts.

May 31, 2016
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