EPSS Colloquium fall-2023

What makes and keeps planets habitable? Taking an Earth-centric view, it is clear that an equitable climate is required, which implicates the carbon and related biogeochemical cycles in regulating habitability. With the ultimate goal of understanding the factors that modulate the carbon cycle, my research group studies the chemistry of modern river systems. The premise behind this work is that rivers integrate over land surface heterogeneity and thus provide a means to relate land surface properties (e.g., climate, rock type, etc.) to the rates of different carbon cycle processes. Our prior work on global river systems revealed an intriguing effect of glacial cover wherein glaciated catchments appear to release carbon dioxide to the atmosphere while non-glaciated catchments consume carbon dioxide. To explore this finding further, we have turned to river systems in Iceland where geologic factors simplify the inverse analysis of river chemistry and climate factors juxtapose catchments with different glacial histories. So far, we have found evidence for an important role of isostatic rebound in modifying carbon fluxes, direct evidence that glaciers enhance weathering over millenial timescales, and more complex water-rock interactions than had previously been assumed.