Rain forest ecosystems play an important role in global functions such as being home to half of the species of plants and animals on the planet, acting as a carbon sink, and moving water from the ground back into the atmosphere. In the Amazon, approximately 50 to 80% of moisture produced remains in the ecosystem’s water cycle. As a result of deforestation and rising global temperatures, less moisture can be moved back into the atmosphere. The objective of this study was to trace how water moves through a rain forest system in order to gain insight on how different species transport water and at what rate. Deuterium (dD of total mixture was 175.58) was added as a tracer to rain in the Biosphere 2 rain forest ecosystem. Samples of soil from various depths, seepage water, and branches from Clitoria racemosa, Hibiscus elatus, Ceiba pentandra and Hura crepitans were collected and their water vapor was analyzed for isotopic levels. Water vapor was analyzed using two methods: IR mass spectrometry and a new method used only before on soil samples. This new sampling method uses inexpensive plastic bags to collect the vapor which is then analyzed on an LGR water isotope analyzer. The results of this study will help to resolve where trees get their water from, how they transport it through their trunks and how this varies by species. This knowledge will also provide information for conservation efforts to maximize tropical forest ecosystem resilience in a dryer world.


Environmental Indicators and Impact Assessment | Hydrology | Soil Science


Joost van Haren

Lab site

Biosphere 2 (B2)

Funding Acknowledgement

This material is based upon work supported by the National Science Foundation through the Robert Noyce Teacher Scholarship Program under grant# 1546150. Any opinions, finding, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The research was made possible by the California State University STEM Teacher Researcher Program in partnership with Biosphere 2 and University of Arizona.



URL: https://digitalcommons.calpoly.edu/star/410


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