Project ID: 2004IN155B

Title: Hydrologic and land use control on the nature and cycling of allochthonous of organic carbon in mixed land use water sheds within Central Indiana

Project Type: Research

Focus Categories: Ecology, Agriculture, Geochemical Processes

Keywords: dissolved organic matter, soil organic matter, particulate organic matter, agricultural drainage, biogeochemistry, stable isotopes, colloids

Start Date: 03/01/2004

End Date: 02/28/2005

Federal Funds: $27,524

Non-Federal Matching Funds: $59,191

Congressional District: 4th

Principal Investigators:
Timothy R. Filley

Chad Jafvert
Purdue University

Abstract

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 allochthonous organic matter (AOM) 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. The ambiguity concerning the biogeochemical cycling of AOM is a function of many factors including the inherent chemical complexity of aquatic organic matter pools, poor temporal sampling resolution, and a lack of application of sophisticated biogeochemical techniques to the study. It is apparent, however, that the bulk AOM transport from soil and litter reservoirs occurs during short-lived hydrologic pulses. Equally important is the recognition that the magnitude and timing of these events have a substantial control upon the nature (e.g. source, reactivity) and turn over time of the organic matter. Similar controls on quantity, quality and size distributions of AOM have been demonstrated in limited occurrences by land use and soils properties (bulk C/N) within drainage basins. The goal of this investigation is to perform a detailed assessment 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. This study will integrate both laboratory and field components combining a detailed molecular, isotopic and physical fractionation of soils and AOM from streams and tile drains.

Progress/Completion Report PDF