Aqueous Chemistry

Abstract

Many of the important inputs, outputs, and internal transfers of elements in watershed ecosystems occur through the medium of water. As water moves through the drainage gradient in a watershed, solution chemistry evolves and changes in response to the differential influences of biogeochemical processes. By tracking changes in aqueous chemistry, it is possible to infer how ions and solutes are influenced by biogeochemical processes that are otherwise invisible and difficult to detect. The intent of this chapter is to examine patterns of solution chemistry in watershed ecosystems and to discuss the major physical, biological, and chemical factors and processes controlling the chemistry and fluxes of elements in natural waters. We shall explore how and why aqueous chemistry varies in space and over time in a watershed. It will become evident that elements do not simply “flush down the drainage pipe” via mass flow and gravity in a watershed ecosystem. Our ultimate goal is to develop a conceptual framework for understanding the individual behavior of different types of ions and solutes in natural waters.