Graduation Semester and Year

Spring 2024

Language

English

Document Type

Thesis

Degree Name

Master of Science in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

Ricardo Sanchez-Murillo

Second Advisor

Maije Fan

Third Advisor

Cornelia Winguth

Abstract

Urban green landscapes have been widely recognized for potentially reducing surface water pollution and flood impacts. However, the understanding of the role that plants play in partitioning the urban water cycle is still limited. We present a study in the Fort Worth Botanic Garden to understand water uptake strategies from three common urban tree species (Elderberry, Sambucus canadensis; Cherry laurel, Prunus caroliniana; and Boxelder maple, Acer negundo) from February 2023 through January 2024. Stem (N=110) isotope ratios (δ18O and δ2H) are compared to multiple endmembers, including precipitation (N=509), throughfall (N=37), and soil water (N=135) at different depths (0- 38 cm). Water from discrete xylem and soil samples was extracted via high-speed vi centrifugation. In addition, soil water samples were obtained from suction lysimeters (N=45) (0-38 cm). Soil and plant water extraction volumes ranged from ~100 µL to 7.5 mL in stem samples and from ~100 µL to 10.5 mL in soil samples. Stem mean narrowband and broadband (proxy for organic contamination) were 0.23±0.40 [-] and 1.00±0.01 [-], respectively. These values agree with mean narrowband and broadband metrics from throughfall and soils. Mean soil δ18O compositions (-3.55±1.72‰) correspond with the throughfall input (-3.60±2.40‰). Stem δ18O compositions exhibited a strong temporal trend from high isotope variability at the end of the winter and summer seasons with more uniform isotope ratios during the growing season (spring). Bayesian mixing analysis showed source water contributions were shallow soil (0cm and 12.7cm) for Boxelder Maple, shallow to deep soil (12.7cm and 25.4cm) for Cherry Laurel, and, remarkably, deep soil (25.4cm and 38.1cm) for Elderberry. Our results contribute to the understanding of water extraction analytical procedures and plant water uptake strategies in a highly altered urban landscape.

Keywords

Ecohydrology, Plant water sources, Centrifugation, Stable isotopes, Water extraction, Water source uptake, Urban water cycle, Urban green infrastructure, Green space, Flood mitigation, Source water partitioning

Disciplines

Hydrology | Water Resource Management

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Available for download on Thursday, November 07, 2024

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