2012


Breanna Skeets

Breanna Skeets


Years participated in RESESS:
2011
2012


An Overview

Major: B.A., Geology
Academic Affiliation: Lawrence University
Research Mentor: Holly Barnard, CU
Computer Mentor: Chris Crosby, UNAVCO
Writing Mentor: Lon Abbott, CU


Biography

Breanna was born on the Navajo Reservation in Gallup, New Mexico and moved with her family to Salt Lake City, Utah at age 7. From the mesas and canyons of New Mexico to the Wasatch Mountains in Utah, her surroundings sparked an interest in geology at a young age. She is passionate about helping underrepresented communities obtain the education they need to better their community. She loves listening to music-- from country to alternative, pop, rock, hip-hop, and even some musicals!


Abstract

Water sources for trees growing on bedrock outcrops

Determining the water source for vegetation is complex due to the poorly understood interactions between soil and surrounding vegetation. Analyzing the relationship between vegetation and subsurface hydrology through stable isotopes furthers understanding of the source water. We compare stable isotope (18O and 2H) values from soil and from xylem samples of trees growing on bedrock outcrops in the Gordon Gulch catchment of the Boulder Creek Critical Zone Observatory, a montane climate ecosystem. We also characterize the study site with respect to vegetation, slope, and topographic wetness index. Aerial LiDAR data provided information pertaining to these spatial characteristics. Initial isotope results indicate that trees are using groundwater sources, transient soil water, or more likely a mixture between the two. A mixture infers that water is coming from a deeper source such as water within fractures, or a less evaporated water source that does not have exposure to the surface. Trees growing on five different rock outcrops all exhibit the same behavior. Our mixing model indicates that all tested trees obtain over 85% of their moisture from groundwater, even in varying moisture conditions. Our spatial analysis indicates the trees growing on outcrops are mostly between 4 to 5 meters tall and that the slopes surrounding the outcrops are between 6 and 20 degrees. The topographic wetness index demonstrates less moisture in close proximity of the rock outcrop.