Biogeochemical cycling of terrestrual organic matter controlled by land use and hydrology

The control of short-lived hydrologic events (e.g. snow melt, storms) and land use (e.g. row crop agriculture) on the nature (source, structure) and reactivity (chemical, biological) of organic matter transferred to streams is poorly understood yet it is of critical importance in understanding a wide range of issues including surface water quality, general aquatic ecosystem function, coastal hypoxia, and even global carbon budgets.

Some of the ambiguity concerning the controls and nature biogeochemical cycling of allochthonous organic matter (AOM) is a function of the inherent chemical complexity of aquatic organic matter pools, poor temporal sampling resolution, and a lack of the application of sophisticated biogeochemical techniques to the study.

The goals of our investigations include detailed assessments of how the nature of soil organic matter and the frequency and intensity of hydrologic pulses control the quantity, source, and size distribution of AOM in mid sized and small agricultural water sheds in Central Indiana that ultimately discharge to the main stem of the Wabash River. Our studies will integrate both laboratory and field components combining detailed molecular, isotopic and physical fractionation of watershed soils and AOM from associated streams and tile drains. We are currently funded by USDA and USGS in this area.