Sagehen Creek Field Station

01 Jun, 02 AM - 30 Jun, 10 AM

The potential transport of nutrients (in particular N and P) from the terrestrial to the aquatic system can play a major role in the continued deterioration of water quality in the eastern Sierras and Lake Tahoe. Prior research has identified the presence of nutrient laden overland/litter interflow as a previously undocumented hydrologic process common to Sierran ecosystems. This overland flow may preferentially infiltrate over spatially distributed forested areas creating biogeochemical ?hot spots? or ?hot moments? relative to the surrounding soil matrix, or move via surface runoff onto downgradient transition ecotones and lowland areas of tributary discharge. Our primary objective is to determine the effects of seasonal preferential infiltration of nutrient rich overland flow on the presence and spatial distribution of nutrient hot spots in mixed conifer Sierran watershed soils and how they are affected by geographic location. This study is important because focusing on nutrient delivery via specific hydrologic flow paths (e.g., preferential infiltration of nutrient laden overland flow)will facilitate development of a better spatio-temporal characterization of nutrient transport within and from Sierran watersheds. The proposed project of determining seasonal spatial and temporal distribution of hot spots and/or hot moments by creating a transect along the Sierra Nevada Mountain Range has been implemented at 5 study locations: Kings River, Little Valley, Sagehen, Truckee, and Castle Lake. Two study types are currently being implemented: a controlled grid analysis and full removal of the O horizon as a .4m? unit for a green house experiment. Strictly in the Sagehen study location the first study type (controlled grid analysis) will be installed at 2 settings: upland and transition ecotone, where one replicate set of 9m? controlled grid analysis plots were generated on the ground in each setting with strategically placed capsules in one grid (half of which will be removed after first precipitation event for comparative analysis) and resin lysimeters in the second. Outside each individual grid two runoff collectors have been placed down slope to intercept any leachate moving overland in the interflow region. Additionally, two snowmelt collectors have been stationed around each set of grids; one in a closed canopy area while the other is in an open setting. Samples from the runoff and snowmelt collectors are being collected periodically after rain or snow events to determine nutrient/ion concentrations (mostly Ortho-p,N,Ca,Mg,& Na). Also, at each study location a rain gauge has been installed. Full removal for lab analysis and cleaning of all sampling material in the field will occur in the spring after the snowmelt cycle followed by an identical reinstallation in the following summer 2010 / fall 2010 months. The second study type consisting of two replicate .4m2 fully intact O horizons which have been removed from each setting and study location have been place in the greenhouse for leaching experiments. The O horizons will be placed onto plexiglass sheets covered with litmus paper. Then a series of misting treatments will be applied for determination of preferential flow paths, spatial heterogeneity and charge detection. This will correlate the spatial and temporal flow patterns between on the ground natural detection of hot spots to those in greenhouse simulation.

Visit #21650 @Sagehen Creek Field Station

Approved

Under Project # 21849 | Research

Analysis of Nutrient Rich "Hot Spots" Across the Sierra Nevada Mountain Range

graduate_student - University of Nevada

Reservation Members(s)

Group of 2 Graduate Student Jun 1 - 30, 2010 (30 days)
Group of 2 Research Assistant (non-student/faculty/postdoc) Jun 1 - 30, 2010 (30 days)

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Day Use 4 Jun 1 - 30, 2010