Isotopic study of sulfate sources and residence times in a subalpine watershed
Stable sulfur and oxygen isotope ratios and naturally occurring 35SSO4 activities were used to examine sulfate sources, address the role of sulfur dynamics, and estimate residence times of atmospherically derived sulfate in Loch Vale Watershed, Colorado. In 1996, surface water samples from small streams flowing through talus, forest, and wetland areas had δ34SSO4 values ranging from 1.8 to 3.7‰. Values of δ18OSO4 at the three sites ranged from –1.3 to 3.7‰. Average δ34SSO4 and δ18OSO4 values in Loch Vale precipitation (1991–1999) are higher (5.2 and 13.6, respectively) than surface water values, indicating that some of the deposited sulfate is transformed and/or mixed with other sulfur sources in the watershed (e.g. mineral and organic sulfur). Sulfate ages determined by 35SSO4 activities support this and show that deposited sulfate may be stored on a timescale of 1 year or more prior to being released to surface waters.
|Publication Subtype||Journal Article|
|Title||Isotopic study of sulfate sources and residence times in a subalpine watershed|
|Series title||Environmental Geology|
|Contributing office(s)||Fort Collins Science Center|
|Google Analytic Metrics||Metrics page|