Seminar Nicole Fernandez

Abstract

Silicate weathering serve a fundamental role in terrestrial water and biogeochemical cycles. Solute generation and mobilization arising from fluid contact with subsurface minerals constituents creates the quality of our surface and groundwaters, sustains ecosystems, shapes the evolution of landscapes, and regulates atmospheric CO₂. Application of mid-mass stable isotopes and trace elements offers a promising approach to characterizing these water-rock interactions and unraveling their controls on observed silicate weathering rates. In this talk, I will build upon our current knowledge of stable isotope and trace element fractionation during water-rock interactions and how they manifest from the laboratory to catchment scale. Focus will center on silicon (Si) stable isotopes and the trace element, germanium (Ge/Si), two complementary tracers that together can offer unique insight into silicate weathering dynamics. I will discuss findings from amorphous silica precipitation experiments, recent efforts involving reactive transport modeling at the pedon-scale, and field observations from a cross-CZO (Critical Zone Observatory) study.

Bio

Dr. Nicole Fernandez is an Assistant Professor at Cornell University. As a low temperature geochemist, A primary focus in Fernandez’s work is the study of fluid-rock interactions at near-surface conditions and how they manifest across various spatiotemporal scales from the mineral-water interface to regional scale river basins. Fernandez relies upon a variety of geochemical tools including stable isotope and trace element environmental tracers to fully characterize the diversity of biogeochemical and hydrologic processes that shape the dynamic landscapes and ecosystems characterizing Earth’s surface.  Her research combines experimental and numerical modeling methods to constrain global water and elemental cycles, their relative feedback, and responses to unprecedented land use changes and a rapidly changing global climate.