Using Isotope Ratios of Respired CO2 in Small Watersheds as Indicators of Ecosystem Function: a Pilot Study

Oregon State University, Corvallis OR

Investigators

Abstract

Carbon has two stable forms, 12C and 13C. Both forms are used in photosynthesis, but plants have a slight preference for 12C, so plants are ENRICHED in 12C compared with atmospheric CO2. Furthermore, the degree of enrichment indicates variations in plant physiology. This knowledge has long been used to study physiology of individual plants; our study applies these concepts to studies of WHOLE ECOSYSTEMS. By sampling air at night at the mouth of small, well-defined watersheds, and analyzing carbon isotopes in respired CO2, we believe we can monitor the physiological responses of the ecosystems within the watersheds to environmental change. We will test this concept in two small watersheds, and will also design and test equipment to automatically sample air for the isotope analyses. At least two undergraduates will be involved in this study each field season.