NREL Seminar: David Williams, Univ. of Wyoming
Friday, November 20, 2009, 11:00 AM
B215, Francis Clark Conference Room, Natural and Environmental Sciences Building

NREL Fall 2009 Seminar Series

Using Stable Isotopes to Understand

Ecological Processes & Global Change

This Friday's seminar will be presented by David Williams, Ph.D., University of Wyoming.

Title: "Plant water use and response to climate change is recorded in the isotopic composition of saguaro cactus spines"

When: Friday, Nov. 20, 11 a.m. to noon

Where: B215, Francis Clark Conference Room, Natural and Environmental Sciences Building

(At right: Dave Williams, Ph.D.)

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Abstract

The long-lived (125-175 yrs) saguaro cactus (Carnegiea gigantea) is a defining element of Sonoran Desert ecosystems in the American Southwest. Saguaro, like other columnar cacti in the New World, provides significant amounts of water, nutrients and energy to consumers during dry periods when other resources are scarce.

Although saguaro plays a central role in the ecology of these fragile ecosystems, its ecophysiological responses to climate variability is still somewhat of a mystery. We have recently discovered that spines grown and retained on saguaro plants throughout their lifetime record information on climate variation and plant physiological response.

Precisely dated, high-resolution measurements of oxygen and carbon stable isotope ratios in spines reveal past patterns of saguaro water supply, microclimate, CAM photosynthetic efficiency and water stress. This talk will describe our initial findings linking saguaro resource use and physiology with the isotope chemistry of spines, and the prospects for resolving long-term records of climate variation and cactus response.

We propose that the spine isotope record documents variation in resource capture and response to climate over the lifetime of individual saguaro plants and provides insight into how decadal climate anomalies (i.e., ENSO and multi-year drought) influence saguaro-based ecosystems in the Sonoran Desert.

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Event Contact: Laurie Richards can be reached at (970) 491-1991

Sponsored by the Natural Resource and Ecology Laboratory.