Identifying and comparing organic carbon source areas in an alpine watershed

Spatial patterns and variation in dissolved organic carbon (DOC) concentration and mass flux were identified in a 7.1 km² alpine basin during the 1985 snowmelt season. Two all-basin reconnaissances were conducted, one prior to and one following peak discharge. Chemical data collected at 98 sites included surface water temperature, pH and specific electrical conductance. Laboratory analysis for DOC revealed values ranging from 0.47 = 8.60 mg C/l. DOC concentration differences between north v. south-facing slopes---and---the lower v. upper basin were not as marked as expected. Mass flux levels showed greater contrast with a strong control by discharge. Of environmental influences on DOC, slope angle displayed the strongest control. Tundra grass commuities produced the highest concentrations among vegetation types. Elevation and slope aspect were shown to be poor predictors of DOC concentration.