3.1 Allochthonous Sources of DOC

One of the earliest studies demonstrating awareness that plant material derived from land surface could be an important source of DOC to groundwater was that of Cronan and Aiken (1985). They showed that DOC produced at land surface from organic detritus had initially high concentrations and that those concentrations decreased rapidly with depth in the soil zone and shallow groundwater. That result was replicated in numerous later studies (Hornberger et al., 1994; Findlay and Sobczak, 1996; Boyer et al., 1997; and Baker et al., 2000). Those studies also showed that DOC delivered to streams by shallow groundwater was ecologically important, providing a carbon source for bacteria that formed the base of stream ecosystems. A generalized model for the delivery, sequestration, and remobilization of allochthonous DOC originating at land surface to groundwater systems is shown in Figure 8.


Dissolved Organic Carbon in Groundwater Systems Copyright © 2022 by Francis H. Chapelle. All Rights Reserved.