SOILS AS BIOGEOCHEMICAL LANDSCAPES

Many environmental issues involve near-surface earth systems, such as soils, that often exhibit complex spatial characteristics and dynamics. Understanding the dynamics and function of soils as biogeochemical systems requires characterizing these systems at both the microscopic and landscape scale. Use of pedologic concepts, as pioneered by Birkeland, has led to new understandings of soils as part of a geochemical landscape.

Soils are spatially heterogenous and dynamic earth systems that contain complex mixtures of mineral phases, organic matter and living organisms, and as such can be considered geochemical landscapes. Soils exhibit a central influence on the fate, transport and bioavailability of contaminants released to the terrestrial environment as well as control on many important biogeochemical cycles. The fate of contaminants in these systems is a function of a diverse number of biogeochemical and hydrologic processes, that depend themselves on the composition and structure of the terrestrial system. Our ability to predict both ecological and human health impacts of human activities and evaluate their potential risk is based upon the quality of our understanding of the composition and function of soils biogeochemistry at the landscape scale.

This talk will examine soils as biogeochemical landscapes through a pedogenic lens as pioneered by Birkeland. I will use examples of our research on uranium and arsenic fate, as well as the historic development of our understanding of the geochemical mechanisms that control sorption, to highlight biogeochemistry at the landscape scale. I will use show how the concepts of Birkeland, Jenny, and the Russian soil scientist Dokuchaev, can be used to understand soils landscape geochemistry and further our understanding of many environmental issues.