HR: 0830h
AN: B21B-0706    [PDF]
TI: Landscape Influences on Organic Matter Export From a Midwestern Watershed
AU: * Dalzell, B J
EM: dalzell@purdue.edu
AF: Purdue University, Dept. of Earth and Atmospheric Sciences 550 Stadium Mall Drive, West Lafayette, IN 47907-1397 United States
AU: Harbor, J M
EM: jharbor@purdue.edu
AF: Purdue University, Dept. of Earth and Atmospheric Sciences 550 Stadium Mall Drive, West Lafayette, IN 47907-1397 United States
AU: Filley, T R
EM: filley@purdue.edu
AF: Purdue University, Dept. of Earth and Atmospheric Sciences 550 Stadium Mall Drive, West Lafayette, IN 47907-1397 United States
AB: In an effort to characterize relationships between landscape processes and organic carbon export, molecular and stable isotope approaches have been applied to particulate, colloidal, and dissolved organic matter samples from Big Pine Creek watershed; an agriculturally-dominated watershed located in west-central Indiana, USA. Preliminary results from multiple sites within the watershed show that organic matter from this 850 km2 watershed is qualitatively similar to samples collected from larger rivers in the western hemisphere, suggesting that small to mid-sized watersheds can play a prominent role in terrestrial organic carbon export. Moreover, carbon-normalized yield data and bulk stable isotope data from the study area show that relationships between export and stream discharge can be dependant on the size fraction of the organic matter. Dissolved organic matter tends to behave linearly with discharge while particulate organic matter responds in a logarithmic manner. Finally, bulk stable carbon isotopes of samples taken from Big Pine Creek show dramatic shifts from base flow to storm flow conditions showing a shift in organic matter sources during flood events. Taken together, these results show that upland conditions can play an important role in the quantity, quality, and source of organic matter exported from terrestrial systems.
DE: 0400 Biogeosciences
DE: 1055 Organic geochemistry
DE: 1615 Biogeochemical processes (4805)
DE: 1806 Chemistry of fresh water
DE: 1845 Limnology
SC: Biogeosciences [B]
MN: 2003 Fall Meeting