Shales, covering 25% of land surface, are an important lithology in linking the CO2 drawdown and continental silicate weathering on the global scale. We are investigating the distribution of total soil carbon, soil CO2 concentrations, dissolved organic carbon (DOC), and soil microorganisms along hillslopes and with soil depth at the Shale Hills Critical Zone Observatory.
Image: Nick Kaiser's summer REU project focused on the measurement of soil respiration in the Shale Hills catchment
Soil Biogeochemistry: We are investigating the distribution of total soil carbon, soil CO2 concentrations, dissolved organic carbon (DOC), and soil microorganisms along hillslopes and with soil depth at the Shale Hills Critical Zone Observatory. These measurements will help us predict how soil microorganisms contribute to the weathering engine, and how soil development affects soil carbon storage and transport in this watershed. Jason Kaye (Department of Crop and Soil Sciences) and Susan Brantley (Geosciences) are interested in soil respiration rates at the Shale Hills Critical Zone Observatory. Soil respiration is the release of CO2 from plant roots and soil heterotrophic organisms to the atmosphere. Kaye’s group is working to quantify how water movement, water storage, and soil texture affect soil-atmosphere exchange rates of CO2. The flux of CO2 from soil is a critical component of the global carbon cycle, yet factors affecting this flux remain unclear.
Figure 1. Concenctrations of dissolved organic carbon (DOC) in a valley floor soil profile consistently show patterns of variation with depth. DOC levels tend to be elevated around 30cm, which likely corresponds to the interface between the Bw and Bt soil horizons.
The ultimate goal of this work is to understand how environmental parameters such as rates of regolith formation can be used to explain the distribution of CO2 and DOC in soils throughout the catchment. By creating this interdisciplinary team consisting of members from Crop and Soil Sciences and Geosciences, we hope to provide a theoretical basis for predicting soil carbon dynamics in shale-derived watersheds around the world.
Contacts: Jason Kaye (PI) and Susan Brantley (PI)
National, Eel, Luquillo, Shale Hills, INVESTIGATOR, COLLABORATOR
Shale Hills, INVESTIGATOR
Cross-CZO GRAD STUDENT
PhD Student (Shale Hills CZO), MS student alumna (Calhoun CZO)
Hot Spots and Hot Moments of Dissolved Organic Carbon Export and Soil Organic Carbon Storage in the Shale Hills Critical Zone Observatory . Andrews, D.M., H. Lin, Q. Zhu, L. Jin, S.L. Brantley. (2011): Vadose Zone Journal 10:943-954
Movement of manganese contamination through the Critical Zone . Herndon, E. M., Brantley S. L. (2011): Applied Geochemistry 26:S40–S43,