Introduction
Carbon, like most biologically significant elements is found in several different isotopic forms. An isotope is an element which varies in the number of neutrons in the nucleus. Carbon with 12 neutrons (12C) is the dominant isotope found in 99.89% abundance compared with the other stable carbon isotope, 13C which is found in 1.11% according to the Pee Dee Belemnite (PDB) standards.
   
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These stable isotopes are important in the study of ecological systems over
time because the different isotopes of carbon (or nitrogen, oxygen, and
hydrogen) are used in different abundances in living things. The ratios
of 12C/13C absorbed and released both into the atmosphere and in various
tissues by plants, animals, and microorganisms are different from the standard
abundances. For example most plants do not fix 13C as readily as they do
12C. Thus the 13C signature of the air changes as plants fix more 12C
then 13C. By measuring changes in the 12C/13C signiture of various plant
and animal tissues, the atmosphere, and at different places in the canopy
much can be learned about biological/physical properties of life.
This website looks into the physiological ecology
of plant's carbon dioxide use by tracing the tool of 13C stable isotope
analysis through the current available literature. Included are
13C analysis of various ecologically pertinent scale levels namely soil,
leaves, canopies, and the atmosphere. Some topics touched upon are are:
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This page was put together as a class project for Phisiological Plant Ecolgy taught by Rob Jackson at Duke University for more pages on various topics in physiological plant ecology go to: bio265.
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