Environmental Biogeochemistry

Element cycles connect the biosphere, atmosphere, lithosphere and hydrosphere on Earth and are central to the evolution of life and the driving forces of our planetary ecosystems. Elements (both “critical” e.g. C, P, S, Fe, Ni, and contaminants e.g. Pb, Cd, Hg, As) move through many chemical states, leaving signatures indicative of the processes which took place over both short and long timescales. These cycles are shaped by soil, microbial and organic matter interactions: erosion of mountains and coastlines exposes new mineral surfaces to weather and contribute to soils and sediments, which, in turn, are impacted through seasonal fluctuations in precipitation, microfauna and nutrient inputs. At SSRL, researchers can take advantage of high-resolution x-ray spectroscopy, EXAFS, x-ray imaging and scattering tools to obtain spatial, temporal and chemical speciation information, yielding insight into how field-relevant factors, like added nutrients, seasonal redox fluctuation, oxygen availability, precipitation and/or microbial activity impact these governing biogeochemical processes. Understanding these processes can play a role in answering important questions related to understanding long timescale geological processes and shaping strategies for soil carbon capture and water quality and contaminant assessment in aquifers.