Effects of Carbon Dioxide (CO2) on Mineral Weathering in Soil- Open System Column Experiments

Geologic carbon sequestration has the potential to reduce carbon dioxide (CO₂) emissions to the atmosphere. However, the potential risks are imperative to know since CO₂ leakage can perturb the geochemistry of the soil. Horseshoe Lake in Mammoth Lakes, CA has a natural occurring CO₂ reservoir which can serve as a parallel to the geologic storage sites. It is CO₂ that reacts with water creating carbonic acid, HCO₃, and the dissociation of this acid promotes weathering of the soil accumulating such minerals as Al, Si, etc. Open-system column experiments are to be performed to mimic the conditions in Mammoth Mountain in order to provide insight on the potential long-term indirect and direct effects of CO₂ seepage on the biogeochemistry of the soil environment. This system is chosen because by imitating a small control volume of the dead tree soil environment in the field site, it can examine mineral weathering and dissolution rates of certain minerals closely. It will also show how the exit mass rate of the minerals could reach a maximum and arrive at an equilibrium. This study will also give a better understanding on the role of CO₂  in leakage circumstances and whether its effects are either more direct or indirect than would be a change in pH in the soil.