Landscape Influences on Organic Matter Export From a Midwestern Watershed
Abstract
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.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.B21B0706D
- Keywords:
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- 0400 Biogeosciences;
- 1055 Organic geochemistry;
- 1615 Biogeochemical processes (4805);
- 1806 Chemistry of fresh water;
- 1845 Limnology