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Plymouth University researchers shed new light on oceans' survival chances

By Plymouth Herald  |  Posted: February 23, 2014

By CARL EVE, Crime Reporter @CarlEveCrime

Triassic fossils

Triassic fossils

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RESEARCHERS at Plymouth University have shed new light on whether the oceans’ can survive climate change.

The new research published today shows how a key ecological group was not wiped out alongside other animals.

Scientists studying the fossil record from the Permian period, 252 million years ago, have discovered for the first time that the ecosystem carried on functioning with a “skeleton crew” of species despite an overall dramatic loss of life due to cataclysmic climate change and rising sea levels.

The findings are published in Nature Geoscience, and could provide new insight into the future state of the world’s oceans as they undergo a similar change.

Professor Richard Twitchett, of the school of geography, earth and environmental sciences, and project lead, said: “The Late Permian extinction was the single largest loss of life in the history of the Earth, and was likely to have been caused by climate change and other environmental factors linked to volcanic eruption.

“Globally it wiped out 90 percent of marine species – but we’ve found evidence that the survivors fulfilled all of the roles needed in the ecosystem. And crucially, not one of the key ecological groups of animals that lived on or within the seafloor, and which keep ecosystems functioning, were completely eliminated”

Professor Twitchett and PhD student William Foster compiled a detailed list of all fossil marine invertebrates known from rocks of that age, mapping where and when they lived in terms of habitat, region and latitude. They worked out how each of the species moved, what they fed upon, and what role they played in the ecosystem. The final database comprised 22,263 individual fossil occurrences and a total of 1,770 genera.

The results showed that while only 20 percent of marine life survived, benthic (seafloor) life fared better, with around 38 percent surviving. Animals that live on and within the seafloor are particularly important in driving global nutrient cycles.

William Foster said: “The fact that none of the key benthic ecological groups were completely eliminated globally during the biggest known extinction recorded in the fossil record was unexpected and demonstrates a certain level of resilience that had not been appreciated before.

“So we might predict that the present changes will not cause complete elimination of these key functional groups, unless future extinctions turn out to be more severe than that experienced 252 million years ago. However, our results also clearly show that some ecosystems do completely collapse, especially tropical ecosystems, in particular reefs.”

The findings also go some way to explaining why there was no subsequent explosion of new animals in the Triassic period.

Professor Twitchett added: “Present day oceans are under threat from climate change, pollution and overfishing and a key scientific problem is to predict how future marine ecosystems may function in the face of such pressures. Understanding how marine ecosystems have responded to past climate change and global mass extinction events may provide some clues.

“In this case, the global oceans in the extinction aftermath were a bit like a ship manned by a skeleton crew: all stations were operational but manned by relatively few species.”

The full report will be available at http://dx.doi.org/10.1038/ngeo2079

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  • Foldart  |  February 24 2014, 8:32AM

    There's no doubt about climate change. The question is, is it a short change? A blip or long-term effect? Then there's the cause. Is it natural or made made. It'll be a long time before anybody knows for sure and using their advanced computer systems at the moment will get them nowhere. Do they think that using technology somehow gives the subject of climate some credibility? They may as well use them to create horoscopes.

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  • DavidNutzuki  |  February 23 2014, 7:00PM

    Science says; evolution "is" fact and smoking "will" cause cancer and comet hits are "inevitable" unlike climate change that science has never agreed beyond; "could" being a crisis. Now you know. "Find us deniers just one single IPCC warning or scientist or science organization that "believes" beyond; "could be" like they say comet hits "will be" "eventual" and "unavoidable"." Don't tell our children that science "believes" as much as you do that the end is near. Your angry weather gods you bow to are laughing now and yes Al Bore, He!! HATH frozen over.

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