Dept. of Geosciences Colloquium: Quantifying Coastal Aquifer Fluxes Through Ocean Chemical Budgets and Groundwater Flow Models

Zoom: https://tau-ac-il.zoom.us/j/87073901428?pwd=Zay3aB8aBEigEH9SC4iEU9pByK9FCN.1

Abstract:

Understanding the ocean's chemical composition is essential for comprehending the carbon cycle and its impact on climate. The direct relation between the ocean's chemical composition and calcium carbonate saturation governs the potential for carbon preservation in sediments. While rivers and hydrothermal circulation have been recognized for their influence, the significance of coastal aquifers has been largely overlooked. Here I show, through an investigation of coastal aquifer groundwater flow mechanisms and chemical composition, that the long-term component of submarine groundwater discharge (SGD) is one of the primary contributors to major element fluxes in the ocean. It predominantly adds calcium alkalinity, on behalf of sodium and potassium. Our analysis of ocean elements and isotopes budgets reveals that the solute fluxes associated with long-term SGD are comparable in magnitude to those of rivers. These fluxes have substantial implications for major element residence time, ultimately impacting the carbon budget and climate. Moreover, these fluxes are closely tied to changes in sea level, whereby decreasing sea levels amplify solute fluxes and increasing sea levels diminish them. Consequently, these fluxes hold the potential to modulate long-term cooling and warming rates on a timescale exceeding 1000 years.

Event Organizer: Dr. Ariel Lellouch