The abyssal ocean: its dynamics and its role in climate
In this lecture I will review recent advances in our understanding of the role played by turbulence in setting the overall structure of the oceans. I will focus on the deep ocean, where the impact of turbulence is strongly modulated by the presence of topography. The presentation will start with some theoretical arguments followed up by results from a very recent field campaign. I will conclude by discussing the implications of these results for our understanding of the global ocean circulation and its role in the...
The Great Unconformity and flooding of North America
The Great Unconformity is an iconic feature across North America marked by the contact between Archean-Proterozoic igneous and metamorphic rocks and overlying Phanerozoic sedimentary rocks. It has been proposed the Great Unconformity was created by extreme erosion associated with Cryogenian Snowball Earth glaciations, which not only delivered limiting nutrients to the ocean that drove the subsequent emergence of animals, but also sent large amounts of sediment to trenches that lubricated subduction zones and...
River networks as ecological corridors for species, populations, and pathogens
Will future large-scale water resources plans make compelling arguments for including the reduction of the loss of biodiversity across scales in fluvial landscapea? Is the structure of river networks a template for large-scale spread of waterborne disease infections? Are we capable to provide solid economic arguments for preventing water development schemes in the light of the social and economic cost of predicted increased burden of disease they would bring? Do biological invasions, including...
Severe convective storms are a significant source of weather-related losses and injury, worldwide. Yet very little is known about what sets their climatology in the current climate, and why climate models generally indicate increased severe storm activity as the climate warms. In this talk, I will focus on one of the main ingredients in severe convective storms: Convective Available Potential Energy (CAPE). The global climatology of CAPE differs significantly from that of deep convection in general; for example, high CAPE values are quite rare over...
Do stomata respond to variations in atmospheric humidity?
A growing literature argues that ecosystem-scale evapotranspiration is more sensitive to drying of the atmosphere because of stomatal regulation by plants than to reductions in surface soil moisture. Past studies analyzed observations, for which it is difficult to conclusively control for potential relations between plant physiology, measurable state variables like vapor pressure deficit (VPD) or soil moisture, and the ecosystem-scale water flux. Here, we analyze natural mechanism-denial experiments at non-vegetated...
From Early Earth to Acid Rain and Agriculture: A Broad Look at the Changing Global Sulfur Cycle
Sulfur (S) is a key component of life and an element that has been dramatically changed by human industrial activities, including mining and fossil fuel combustion. Today, the nature of how humans alter the global S cycle is changing. As atmospheric S deposition has declined in response to air quality regulations in the United States and Europe, there has been an increase in S fertilizer applications reported in many large-scale regional crop systems. In addition, intensification...
Earthquake Nucleation and Foreshock Mechanisms: cascade triggering, pre-slip, or fluid flows?
Understanding the nucleation process of large earthquakes is crucial for accurate earthquake prediction and seismic hazard mitigation. While earthquake nucleation process has been widely observed in the laboratory and numerical simulation, it is difficult to observe them directly in the field. Some studies have considered foreshocks as the by-product of such nucleation process. Many large earthquakes also have...
‘Picking your path’ towards accessible and inclusive geoscience field education
Fieldwork is a critical aspect of geoscience education and there is now a substantive body of research-informed evidence to support its continued inclusion in the undergraduate geoscience curriculum. However, while the value of fieldwork for understanding the Earth and Earth processes is well established, fieldwork as an activity is not inclusive or accessible for all students. This is particularly true for students with disabilities who can encounter multiple barriers to participating in...
