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Thursday, September 15, 2011

Educational “enrichment” in the Prairie

As you know, the Berry Prairie is more than just a green roof.  It's also a tool for education, and in many ways.  
  • Exhibit A:  Kyle is a graduate student in botany studying the green roof for his master's project (meet Kyle by clicking here).  
  • Exhibit B:  Children visited the Berry Prairie to learn about how pollinators and plants are so closely connected (read more about that by clicking here). 
  • Exhibit C:  The EPA is interested in learning from our green roof model to examine how green roofs can be sustainable and viable options (read up about that here and here).
  • Exhibit D: Yesterday, a freshman Earth Systems Science class came through the green roof to talk about types of research projects they might do for their class project, and also conduct simple measurements of biodiversity.

Exhibit E: Stable Isotope Ecology
And another, really cool way the Berry Prairie is helping students learn is through Dave Williams' (UW Botany and Renewable Resources departments, also the faculty director of the Stable Isotope Facility) Stable Isotope Ecology class.  If you don't know what a stable isotope is, you're not alone - it's a cutting edge scientific method to look at how biological organisms (plants, animals, humans, etc.) lived.  For example, by looking at the stable isotopes of animal fur, one can determine approximately where the animal lived, what kind of diet it had, if it was mobile or stationary, and more.

The post below is written by Dave, explaining the goals and the methods of his Stable Isotope Ecology class and why they used the Berry Prairie for their sample source.  You can contact Dave at with any questions about stable isotopes or ecology.


Here's Dave Williams, UW Professor of Botany and Renewable Resources, and the Faculty Director of the Stable Isotope Facility in the Berry Center.

Educational “enrichment” in The Berry Prairie – students investigate isotopes and plant transpiration

Plant species in the Berry Prairie respond to environmental changes in quite unique ways. Very often, physiological responses of prairie plants to changes in the environment are recorded in the stable isotope ratios of hydrogen, oxygen, carbon and nitrogen of plant tissues. 

Students from the graduate course “Stable Isotope Ecology” (RNEW 5500) trekked out to the Berry Prairie during the second week of classes this fall semester (2011) to collect soil, stem and leaf samples from different prairie species. The students spent several hours in the Stable Isotope Facility afterward extracting water from the samples to then determine the ratio of heavy to light isotopes of hydrogen and oxygen in the water using state-of-the-art analytical instruments. 

Students sample a sagebrush (Artemisia tridentata wyomingesis) to analyze in the Stable Isotope Facility.

Students take samples of a harebell (Campanula rotundifolia) to study its isotopic story.

The goal was to test ideas about how water in foliage becomes enriched in heavy isotopes (2H and 18O) during transpiration. The degree of isotope enrichment of water in foliage is determined by conditions of temperature and humidity, and this isotope ratio value then gets recorded in sugars and other organic compounds, like the cellulose that makes up tree rings. Leaf water also imprints an isotope ratio fingerprint on CO2 in the atmosphere, which has proven to be a useful marker for determining the terrestrial contribution to changes in the global carbon cycle. 

Craig Cook (center, in blue), the Facility Director of the Stable Isotope Facility, instructs students on the processes of stable isotope analysis.

The Stable Isotope Facility is a state-of-the-art facility built entirely for the purpose of analyzing samples like these.

The students’ initial results have revealed very different patterns of water use by plants in the Berry Prairie that might be related to how the different species balance transpiration losses with CO2 uptake during photosynthesis. 

The data processing is just in the initial phases, so there is more to come from this work!

Written by Brenna Wanous, Berry Center, and Dave Williams, UW Botany, Renewable Resources and Stable Isotope Facility

Resident photographer: Dorothy Tuthill, Berry Center Associate Director 

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