Landscape dynamics over geological timescale

Tristan Salles, The University of Sydney

Video Recording

Slides

Abstract:
The long-term diversification of the biosphere responds to changes in the physical environment, whether geological or climatic. Yet, over the continents, the nearly monotonic expansion of life started later in the early Phanerozoic (540 million years ago) than in the marine realm, where instead the number of genera waxed and waned over time. A comprehensive evaluation of the changes of the geodynamic and climatic forcing misses to provide a unified theory for the long-term pattern of evolution of life on Earth. In this presentation, I will discuss recent work coupling climate and plate tectonics models to numerically reconstruct the evolution of the Earth’s physiography over the past 540 million years (Phanerozoic eon). These models are then compared to paleo-diversity datasets from marine animal and land plant genera. Our results suggest that biodiversity is strongly reliant on landscape dynamics, which at all times determine the carrying biodiversity capacity of both the continental and oceanic domains. In the oceans, diversity closely adjusted to the riverine sedimentary fluxes that provide nutrients for primary production. On land, plant expansion was hampered by poor edaphic conditions until widespread endorheic basins resurfaced continents with a sedimentary cover that facilitated the development of soil-dependent rooted flora, while the increasing variety of the physiography additionally promoted their development.

Bio:
Tristan’s research areas revolve around sediment transport, landscape evolution, coral reefs and ocean dynamics. He leads the EarthCoLab research group and his main activities consist in the design and implementation of open-source numerical codes that improve our understanding of the complex interactions between Earth’s surface, climate, tectonic, and its relationships to biodiversity. He moved to the University of Sydney in 2015 after working for 8 years at the Commonwealth Science & Industry Research Organisation (CSIRO). He did his degree in France in marine engineering and physical oceanography with a PhD in marine geoscience. Over the past 3 years, he has been designing holistic approaches enabling cross-disciplinary research by linking data to whole Earth models across temporal and spatial scales.

Summary: