Open AccessAn experimental evaluation of the use of C 3 δ 13 C plant tissue as a proxy for the paleoatmospheric δ 13 CO 2 signature of air
Author(s) -
Lomax B. H.,
Knight C. A.,
Lake J. A.
Publication year - 2012
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2012gc004174
Subject(s) - isotopes of carbon , isotope , stable isotope ratio , analytical chemistry (journal) , carbon fibers , chemistry , atmospheric sciences , geology , mineralogy , physics , environmental chemistry , materials science , nuclear physics , composite number , composite material
Previous work suggests that the relationship between the carbon isotope composition of air ( δ 13 C a ) and plant leaf tissue ( δ 13 C p ) can be used to track changes in the carbon isotope composition of paleo‐atmospheric CO 2 . Here we test this assertion in a series of experiments using the model plant Arabidopsis thaliana grown under a range of atmospheric CO 2 concentrations relevant to geologic time (380, 760, 1000, 1500, 2000 and 3000 ppm). Nested within these CO 2 experiments water availability was controlled (giving two sets of experimental plants; low and high water treatment at each CO 2 concentration) to manipulate stomatal opening, a key process governing carbon fixation and isotope discrimination. Results show a highly significant relationship between δ 13 C a and δ 13 C p under both experimental water treatments. To test the utility of δ 13 C p to predict δ 13 C a we compare calculated δ 13 C a to measured values of δ 13 C a . These data show that although there is a significant relationship between calculated and measured δ 13 C a , there is disparity between the two values of δ 13 C a and a large difference between calculated values under different water treatments even when grown in a common CO 2 concentration. These results demonstrate that environmental factors that alter stomatal opening can severely impact on the use and reliability of δ 13 C p to predict δ 13 C a and as such, results should be interpreted with caution.