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Reconstructing the response of C3 and C4 plants to decadal-scale climate change during the late Pleistocene in southern Illinois using isotopic analyses of calcified rootlets

Quaternary Research

By:
and
DOI: 10.1016/j.yqres.2006.10.001

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Abstract

The ??13C and ??18O values of well-preserved carbonate rhizoliths (CRs) provide detailed insights into changes in the abundance of C3 and C4 plants in response to approximately decadal-scale changes in growing-season climate. We performed stable isotope analyses on 35-40 CRs sampled at 1-cm intervals from an 18-cm-thick paleosol formed in southern Illinois during Wisconsin interstadial 2. Minimum ??13C values show little variation with depth, whereas maximum values vary dramatically, and average values show noticeable variability; maximum ??18O values vary less than the minimum ??18O values. These findings indicate that a diverse and stable C3 flora with a limited number of C4 grass species prevailed during this interval, and suggest that the maximum growing-season temperatures were relatively stable, but minimum growing-season temperatures varied considerably. Two general patterns characterize the relationships between the ??13C and ??18O values obtained from the 1-cm samples. In some cases, low ??13C values correspond to low ??18O values and high ??13C values correspond to high ??18O values, suggesting that cooler growing-season temperatures favored C3 and warmer growing-season temperatures favored C4 plants. In other cases, low ??13C values correspond to high ??18O values, likely suggesting that wetter growing-season conditions were favorable to C3 plants. The high density of well-preserved CRs in this paleosol provides a unique opportunity to study detailed ecological responses to high-resolution variability in growing-season climate. ?? 2006 University of Washington.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Reconstructing the response of C3 and C4 plants to decadal-scale climate change during the late Pleistocene in southern Illinois using isotopic analyses of calcified rootlets
Series title:
Quaternary Research
DOI:
10.1016/j.yqres.2006.10.001
Volume
67
Issue:
1
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Research
First page:
136
Last page:
142
Number of Pages:
7