Science Atlantic Speaker Tour

The Science Atlantic Geology Speaker Tour is co-sponsored by the Atlantic Geoscience Society. In this annual speaker tour, prominent scientists visit several post-secondary institutions in Atlantic Canada. The lectures are free and open to anyone interested in attending. More details can be found on the Science Atlantic website.

2023-2024 Speaker Tour

The Sedimentary Record of Oxygen and the Evolution of Animals: Revising the Phanerozoic Paradigm using Ironstones and More!

Dr. Ted Matheson, Assistant Professor, Cape Breton University

January 16, 2024: University of New Brunswick
January 17, 2024: Acadia University
January 18, 2024: Dalhousie University

Abstract: Earth’s oceans and atmosphere have not always been as rich in oxygen as they are today. At the broadest scale, Earth has undergone a series of steps and progressive increases from a completely anoxic planet to a well-oxygenated one capable of supporting a diverse biosphere. Understanding this oxygenation history is integral to deciphering the importance of oxygen in the evolution of complex multicellular life such as animals. Sedimentary rocks, both the facies and attributes of the rocks themselves, as well as geochemical proxies preserved within them, serve as the archive for this ancient Earth system evolution.

One temporal interval of particular importance is the early Paleozoic (ca. 539 to 419 million years ago), a time of two of Earth’s largest biodiversification events. It was long believed that a major step towards full oceanic oxygenation occurred during the Neoproterozoic Oxygenation Event, prior to the Paleozoic, leading to a traditional interpretation of early Paleozoic oceans that were well oxygenated, as was thought necessary to support metazoan biodiversification. However, it is increasingly apparent that earth scientists’ knowledge of the oxygenation of our oceans during this period is incomplete. Over the last decade, new data has argued the traditionally held narrative. We now believe that the early Paleozoic was a time of heterogenous and relatively low marine oxygen concentrations, with present-day levels not reached until the late Paleozoic. The record, details, and significance of this drawn-out oxygenation are not fully understood. One of the newest redox proxies shedding light on this topic lies in understanding the genesis of Paleozoic metalliferous sedimentary rocks. In this talk, I’ll combine a holistic overview of this enigmatic interval with a focus on the unique interpretations that have come out of the recent sedimentologic, stratigraphic, and geochemical study of ironstones, marine red beds, and manganiferous carbonate in Canada and globally.

Bio: Ted Matheson is an Assistant Professor of Geology at Cape Breton University in Sydney and an Adjunct Professor at Queen’s University in Kingston, Ontario. Ted joined the faculty at CBU after a PhD at the University of Nebraska-Lincoln and postdoctoral fellowships at Queen’s University and with Nutrien Potash in Saskatchewan. His research interests lie in using sedimentary rocks to reconstruct ancient Earth environments with a focus on the evolution of the oceans and climate.

Fuelling Forests: Nitrogen Cycling and Projecting Climate Change

Dr. Sian Kou-Giesbrecht, Assistant Professor, Dalhousie University

January 22, 2024, Memorial University of Newfoundland and Labrador
January 30, 2024: Saint Francis Xavier University
February 16, 2024: Saint Mary’s University

Abstract: The terrestrial biosphere currently sequesters a third of human CO2 emissions in plant and soil biomass, and is known as the “terrestrial carbon sink”. However, the terrestrial carbon sink needs nutrients such as nitrogen to fuel plant growth. A major challenge for future climate change projections is resolving how much nitrogen will constrain plant growth and carbon sequestration in the future under global change. In this talk, I will explore how nitrogen cycling is represented within terrestrial biosphere models, which are used within the framework of Earth System Models to project climate change. I will also explore aspects of nitrogen cycling in forests, how it is influenced by global change, and how our empirical understanding can help improve terrestrial biosphere models and their projections of the terrestrial carbon sink and climate change.

Bio: Sian is a new professor at Dalhousie University in the Department of Earth and Environmental Sciences. Her research interests are broadly in terrestrial ecosystem ecology, carbon and nitrogen cycling, global change, and terrestrial biosphere modelling and Earth system modelling.