1312th OGM and 2019 Clarke Memorial Lecture
“Reconstructing ancient oceans, sea-level fluctuations, the deep carbon cycle and biodiversity ”
Professor Dietmar Müller FAA FAGU
Professor of Geophysics
School of Geosciences
University of Sydney
Date: Wednesday, 5 April 2023, 6.00 pm for 6.30 pm AEDT
Venue: Gallery Room, State Library of NSW, Shakespeare Place, Sydney
Video presentation: YouTube video
All are welcome
Summary: This presentation is a journey through geological time, reconstructing ancient oceans that have little resemblance to the oceans we know today. These reconstructions are enabled by the EarthByte Group’s Virtual Earth Observatory, powered by the GPlates software. They represent decades of software development and geodata synthesis to recreate now vanished ocean basins. These digital maps form the basis for understanding the driving forces of changes in ocean basin volume and long-term sea-level, the deep carbon cycle and biodiversity. Our models track oceanic carbon reservoirs through time and demonstrate that the carbon storage and transport capacity of the oceans, from mid-ocean ridges to subduction zones, has increased 5-fold since the breakup of the Pangea supercontinent 200 million years ago, reflecting the emergence of biogenic deep-sea carbonate sediments as the largest carbon reservoir on Earth. Our maps have also been used to reconstruct marine biodiversity. An ocean evolution model over 550 million years, validated with fossil data, shows that modern ocean biodiversity, which is at its highest level ever, was achieved through long-term stability of the location of so-called biodiversity hotspots. These are regions of especially high numbers of species located in warm, shallow, nutrient-rich waters. This study also emphasises that, if current trends continue, projected diversity loss can take millions of years to recover, arguably beyond our own existence as a species.
Dietmar Müller is Professor of Geophysics at the School of Geosciences, University of Sydney. He received his undergraduate degree from the Univ. of Kiel, Germany, and his PhD in Earth Science from the Scripps Institution of Oceanography, UC San Diego/California in 1993. After joining the University of Sydney he built the EarthByte Research Group, pursuing geodata synthesis through space and time. He is leading the construction of a Virtual Earth Laboratory, assimilating the wealth of disparate geological and geophysical data into an experimental planet. Dietmar’s virtual globe software and data are benefiting universities, government organisations, industry and schools worldwide, with end-users across over 190 countries. Novel applications include the development of combined geodynamic, tectonic and surface evolution models unravelling the origins and history of continental landscapes, coastlines, oceans and their environments. He held an Australian Laureate Fellowship from 2009-2014, and is a Fellow of the American Geophysical Union, and the Australian Academy of Science.
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