Discharge and source of particulate organic carbon and nitrogen from a small mountainous river in the Oregon Coast Range
Abstract
The discharge of POC from small mountainous rivers (SMR) may contribute nearly half of the world's POC to the ocean. Understanding POC and PON quality will give us clues about the material's stability in the coastal environment and also its source within the watershed. During the 2007-2008, we collected samples from the Alsea River in the Oregon Coast Range that span a broad range of discharges that include base flow and a 5-year flood. Fine (<63 μm) and coarse (>63 μm) particulate material was analyzed for OC, N, stable isotopes (δ13C and δ15N), and cupric oxide (CuO) oxidation products (e.g. lignin). With increasing discharge the source and quality of fine POC and N appears to become more soil-like. The POC and N of the coarse particles appear to be affected by an increase in lithogenic material; however, the stable isotope and biomarker data indicate that the majority of the C and N were derived from a constant source (mainly "fresh" detritus). This study shows that OC and N quality, and source, in small mountainous rivers are controlled by discharge, which must be taken into account when studying the sources, transport and transformation of biogeochemical materials in these and other aquatic systems.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.H21H0939H
- Keywords:
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- 0428 Carbon cycling (4806);
- 0469 Nitrogen cycling;
- 1821 Floods;
- 1862 Sediment transport (4558)