The Royal Society of NSW Clarke Memorial Open Lecture on Wednesday 5 April 2023 will be delivered by Dietmar Müller on “Reconstructing ancient oceans, sea-level fluctuations, the deep carbon cycle and biodiversity”. Venue: Gallery Room, State Library of NSW, Shakespeare Place
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 emphasizes that, if current trends continue, projected diversity loss can take millions of years to recover, arguably beyond our own existence as a species.