Erica Almance /Earth & Environmental Sciences / Faculty Mentor: Ricardo Sanchez-Murillo
The role of plants in controlling the urban water cycle in a changing climate remains poorly understood and enigmatic. Here, we present a novel one-year study of water sourcing in Elderberry, Cherry Laurel, and Boxelder Maple during a La Niña to El Niño transition in the Dallas-Fort Worth Metroplex. Stem, root, and soil water isotopologues extracted via centrifugation and analyzed via laser spectroscopy are compared to endmembers, including rainfall, throughfall, surface water, and soil water. Stem δ18O compositions exhibited a strong temporal trend from high variability at the end of winter (old, stored water) and summer (water stress), with more uniform isotope ratios during spring and fall seasons. Overall, stem δ18O compositions concurred with seasonal soil water isotope ratios. Boxelder Maple displayed a root-to-stem enrichment of 2.62‰, with highly variable δ18O values (-4.62‰ to 0.2‰) across root sections and seasons, suggesting a transition from deep soil water to shallower sources. Similarly, Cherry Laurel roots showed significant variability (-5.61‰ to 4.86‰) within root sections, implying access to different soil depths. Our results contribute to understanding water extraction analytical procedures and demonstrate versatile plant water uptake strategies across a highly altered urban landscape under water stress conditions.
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