TY - JOUR
T1 - Leaf cellulose δD and δ18O trends with elevation differ in direction among co-occurring, semiarid plant species
AU - Terwilliger, Valery J.
AU - Betancourt, Julio L.
AU - Leavitt, Steven W.
AU - Van De water, Peter K.
N1 - Funding Information:
We thank F. Stein and C. Dunbar for their help in the field. F. Stein, C. Dunbar, T. Buller, and X. Zhang helped with offline preparations for isotopic analyses, and Dr. D. Le Roux-Swarthout helped with isotopic analyses on the dual inlet. Dr. S. Madhavan provided intellectual input and mass spectrometry guidance. Dr. R. Fagan and E. Negreanu performed the online isotopic analyses. E. Pendall’s thoughtful comments improved an earlier draft of the manuscript. C. Sheltz provided permits to collect plant tissues in Natural Bridges National Monument. This work was funded by the National Science Foundation (SBR-9631420 to VJT and EAR-9418268 to SWL and JLB).
PY - 2002/11/15
Y1 - 2002/11/15
N2 - The potential to reconstruct paleoclimate from analyses of stable isotopes in fossil leaf cellulose could be enhanced by adequate calibration. This potential is likely to be particularly great in mid-latitude deserts, where a rich store of fossil leaves is available from rodent middens. Trends in δD and δ18O of leaf cellulose were examined for three species growing across climatic gradients caused by elevation and slope aspect in southeastern Utah, USA. The species differed in morphology (Pinus edulis vs. Yucca glauca), photosynthetic pathway (C3 Y. glauca vs. CAM Yucca baccata) or both (P. edulis vs. Y. baccata). The δDLCN (leaf cellulose nitrate) and δ18OLC (leaf cellulose) values of P. edulis decreased with elevation. Stem water δD values either increased (in spring) or did not change with elevation (in summer). Needle water δD values usually decreased with elevation and differed greatly with leaf age. These results suggest that δ cellulose values of P. edulis record the effects of climate on the isotopic composition of leaf water but not climate effects on meteoric water. In contrast to P. edulis, δDLCN values of Y. glauca increased with elevation. The δ18O LC values ofc Y. glauca also increased with elevation but less significantly and only on south-facing slopes. The δ cellulose values in both P. edulis and Y. glauca were most significantly related to changes in temperature, although temperature and precipitation were negatively correlated in the study area. Where all three species co-occurred, their δDLCN values differed but their δ18O LC values were the same. The disparity in δDLCN between Y. baccata and the other species corresponds to differences in biochemical fractionations associated with photosynthetic pathway. Biochemical fractionations may also contribute to differences between the two C3 species. Knowledge of factors affecting responses of individual plant species to environment may be required to infer climate from δDLCN and δ18OLC.
AB - The potential to reconstruct paleoclimate from analyses of stable isotopes in fossil leaf cellulose could be enhanced by adequate calibration. This potential is likely to be particularly great in mid-latitude deserts, where a rich store of fossil leaves is available from rodent middens. Trends in δD and δ18O of leaf cellulose were examined for three species growing across climatic gradients caused by elevation and slope aspect in southeastern Utah, USA. The species differed in morphology (Pinus edulis vs. Yucca glauca), photosynthetic pathway (C3 Y. glauca vs. CAM Yucca baccata) or both (P. edulis vs. Y. baccata). The δDLCN (leaf cellulose nitrate) and δ18OLC (leaf cellulose) values of P. edulis decreased with elevation. Stem water δD values either increased (in spring) or did not change with elevation (in summer). Needle water δD values usually decreased with elevation and differed greatly with leaf age. These results suggest that δ cellulose values of P. edulis record the effects of climate on the isotopic composition of leaf water but not climate effects on meteoric water. In contrast to P. edulis, δDLCN values of Y. glauca increased with elevation. The δ18O LC values ofc Y. glauca also increased with elevation but less significantly and only on south-facing slopes. The δ cellulose values in both P. edulis and Y. glauca were most significantly related to changes in temperature, although temperature and precipitation were negatively correlated in the study area. Where all three species co-occurred, their δDLCN values differed but their δ18O LC values were the same. The disparity in δDLCN between Y. baccata and the other species corresponds to differences in biochemical fractionations associated with photosynthetic pathway. Biochemical fractionations may also contribute to differences between the two C3 species. Knowledge of factors affecting responses of individual plant species to environment may be required to infer climate from δDLCN and δ18OLC.
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U2 - 10.1016/S0016-7037(02)00964-X
DO - 10.1016/S0016-7037(02)00964-X
M3 - Article
AN - SCOPUS:0037110721
SN - 0016-7037
VL - 66
SP - 3887
EP - 3900
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 22
ER -