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Friday, 15 January 2010

Microfossils of extinct eel-like animals, known as conodonts, and the spores of the earliest plants, similar to mosses and liverworts, will be examined by researchers assessing the effects of sea surface temperature and atmospheric carbon dioxide on the origin, expansion and extinction of species over hundreds of millions of years.

Aiming to provide new insights into how life evolved and survived major environmental upheaval, the researchers, led by Assistant Professor Julie Trotter at The University of Western Australia's School of Earth and Environment, have been funded by an Australian Research Council Discovery grant of more than $350,000.

"Some fossils can be excellent archives of environmental change," Asst/Professor Trotter said.  "We aim to determine the roles that temperature and carbon dioxide played in the evolution of the biosphere and reconstruct the links and feedbacks between climate systems and bio-events."

The first phase of their project will involve estimating seawater temperatures throughout a period of about 300 million years, from the late Cambrian to the Triassic when conodonts lived.  Temperatures can be estimated by measuring the oxygen isotope ratios of conodont phosphatic ‘teeth'.

The second phase will involve modelling atmospheric carbon dioxide levels from the carbon isotope measurements of fossil spores, and assessing the trends in temperature and carbon dioxide through time.  In the third phase, the researchers will conduct higher resolution analyses focused on key periods in Earth history, to identify links between sea surface temperatures, carbon dioxide, and major evolutionary changes in the biosphere.

These study periods will target contrasting environments, from a marine-based world in the late Ordovician (about 450 million years ago) when CO 2 is believed to have been high and glaciations ensued leading to major extinctions (60 per cent of genera); the Carboniferous (about 300 million years ago) when CO 2 was low and colonisation of the land was extensive; and the late Permian-Triassic, a time of intermediate but increasing CO 2 that saw the largest extinction event (80 per cent of genera) in Earth history.

These environmental records will be assessed in the context of important geological processes, such as tectonics, weathering, sea level, and landmass configuration that have changed greatly over time, and play a critical role in ocean circulation hence regional and global climate.  Dr Ian Williams of the Australian National University; Emeritus Professor Chris Barnes of the University of Victoria in Canada; and Professor David Beerling and Dr Charles Wellman, both of the University of Sheffield, are the other members of the team.

Media references

Assistant Professor Julie Trotter (+61 8)  6488 3925  /  (+61 4) 18 232 480
Sally-Ann Jones (UWA Public Affairs)  (+61 8)  6488 7975  /  (+61 4) 20 790 098

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