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Carbon dynamics in the hyporheic zone of a headwater mountain stream in the C ascade M ountains, O regon
Author(s) -
CorsonRikert Hayley A.,
Wondzell Steven M.,
Haggerty Roy,
Santelmann Mary V.
Publication year - 2016
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2016wr019303
Subject(s) - hyporheic zone , dissolved organic carbon , riparian zone , hydrology (agriculture) , groundwater , vadose zone , environmental science , subsurface flow , surface water , soil water , total organic carbon , streams , geology , soil science , environmental chemistry , oceanography , ecology , chemistry , environmental engineering , geotechnical engineering , computer network , computer science , habitat , biology
We investigated carbon dynamics in the hyporheic zone of a steep, forested, headwater catchment western Oregon, USA. Water samples were collected monthly from the stream and a well network during base flow periods. We examined the potential for mixing of different source waters to explain concentrations of DOC and DIC. We did not find convincing evidence that either inputs of deep groundwater or lateral inputs of shallow soil water influenced carbon dynamics. Rather, carbon dynamics appeared to be controlled by local processes in the hyporheic zone and overlying riparian soils. DOC concentrations were low in stream water (0.04–0.09 m M ), and decreased with nominal travel time through the hyporheic zone (0.02–0.04 m M lost over 100 h). Conversely, stream water DIC concentrations were much greater than DOC (0.35–0.7 m M ) and increased with nominal travel time through the hyporheic zone (0.2–0.4 m M gained over 100 h). DOC in stream water could only account for 10% of the observed increase in DIC. In situ metabolic processing of buried particulate organic matter as well as advection of CO 2 from the vadose zone likely accounted for the remaining 90% of the increase in DIC. Overall, the hyporheic zone was a source of DIC to the stream. We suggest that, in mountain stream networks, hyporheic exchange facilitates the transformation of particulate organic carbon buried in floodplains and transports the DIC that is produced back to the stream where it can be evaded to the atmosphere.