Publication Date:
2018-01-06
Description:
Considerable CO 2 evasion to the atmosphere occurs as DIC is transported from soils to streams. While this physical process has been the focus of multiple studies, less is known about the underlying biogeochemical transformations that accompany this transfer of C from soils to streams. Here, we used patterns in streamwater and groundwater δ 13 C-DIC values within three headwater catchments with contrasting land-cover to identify the sources and processes regulating DIC during its transport. We found that although considerable CO 2 evasion occurs as DIC is transported from soils to streams, there were also other processes affecting the DIC pool. Methane production and mixing of C sources, associated with different types and spatial distribution of peat-rich areas within each catchment, had a considerable influence on the δ 13 C-DIC values in both soils and streams. These processes represent an additional control on δ 13 C-DIC values and the catchment-scale cycling of DIC across different northern landscape types. The results from this study demonstrate that the transport of DIC from soils to streams results in more than just rapid CO 2 evasion to the atmosphere, but also represents a channel of C transformation, which questions some of our current conceptualizations of C cycling at the landscape scale.
Print ISSN:
0148-0227
Topics:
Biology
,
Geosciences
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