Soil Biogeochemistry in the Critical Zone

The critical zone (CZ) is the interface of geologic, atmospheric, biologic, and hydrologic processes at the Earth’s surface that are critical for life. This zone extends from shallow groundwater to the top of the vegetative canopy. Biogeochemical cycling in the CZ largely determines the terrestrial feedbacks to climate change as well as the influence of terrestrial processes on the atmosphere and hydrosphere.

The focus of this project is to quantify biogeochemical processes in the CZ with an emphasis on the interactions among soil, water, and plants. We explore the role of atmospheric CO₂ and climate variability on mineral weathering and soil chemistry, to understand the influence of these factors on water chemistry.

Why is this research important?

The dynamic interactions of biogeochemical cycling and climate in the CZ are of great concern to society as they exert direct and indirect influences on water quality, soil productivity & health and human health. Despite the importance of the CZ, our understanding of the interconnectedness and resiliency of CZ processes remains limited. For instance, differences in soil mineralogy, hydrology, and/or biologic communities has a large influence on the amount of carbon that is stored in the soil. In order to better understand what soils are most susceptible to climate and landuse change as well as what soils may have the greatest potential for future carbon storage, we use a systematic framework to quantify soil development and to link it to soil biogeochemical cycling. Quantifying these relationships is essential for predicting the response of terrestrial ecosystems to climatic change and is vital to framing environmental management strategies.

Principal Investigator: Marjorie S Schulz, Menlo Park Science Center

Project Team: Corey Lawrence, Dave Stonestom