Analysis of Dissolved Organic Matter in Agricultural Runoff

Dissolved organic matter (DOM) is the variety of molecules composed primarily of carbon, hydrogen in surface waters and groundwater that are typically leached from plants and soils. This mobile group of molecules plays a key role in biogeochemical processes, ecological processes, and the global carbon cycle. The composition of this organic matter can vary greatly depending on its original source and the degree to which it is broken down by microbial activity.

It is well known that the runoff from agricultural fields is often high in nutrients such as nitrogen, phosphorus, and potassium, which are common constituents in fertilizer. In addition, agricultural runoff can contain high levels of dissolved organic matter. Previous research has suggested that DOM in agricultural runoff differs in character from DOM in natural stream systems, and may be more available to microbes as a nutrient source. Additionally, there is concern that the total mass of DOM exiting agricultural fields is higher than that exiting naturally vegetated land. The goal of this project is to quantify the fluxes and character of DOM exiting an agricultural field and compare these data to a naturally vegetated stream.

Water samples will be taken when flow is generated in an intermittent channel that drains an agricultural field, as well as from a control stream. Samples will be filtered in the laboratory and analyzed to understand the character of the compounds they contain. I will be using several different methods in the lab to do this.