Paleozoic Paleobotanical Atmospheric CO2 Reconstruction ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Paleozoic Paleobotanical Atmospheric CO2 Reconstruction LAST UPDATE: 5/2006 (Original receipt by WDC Paleo) CONTRIBUTOR: Jennifer McElwain, Field Museum of Natural History, Chicago. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2006-046 SUGGESTED DATA CITATION: McElwain, J.C. and W.G. Chaloner. 2006. Paleozoic Paleobotanical Atmospheric CO2 Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2006-046. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: McElwain, J.C. and W.G. Chaloner. 1995. Stomatal Density and Index of Fossil Plants Track Atmospheric Carbon Dioxide in the Palaeozoic. Annals of Botany, Vol. 76, pp. 389-395. ABSTRACT: It has been demonstrated that the leaves of a range of forest tree species have responded to the rising concentration of atmospheric CO2 over the last 200 years by a decrease in both stomatal density and stomatal index. This response has also been demonstrated experimentally by growing plants under elevated CO2 concentrations. Investigation of Quaternary fossil leaves has shown a corresponding stomatal response to changing CO2 concentrations through a glacial-interglacial cycle, as revealed by ice core data. Tertiary leaves show a similar pattern of stomatal density change, using palynological evidence of palaeo-temperature as a proxy measure of CO2 concentration. The present work extends this approach into the Palaeozoic fossil plant record. The stomatal density and index of Early Devonian, Carboniferous and Early Permian plants has been investigated, to test for any relationship that they may show with the changes in CO2 concentration, derived from physical evidence, over that period. Observed changes in the stomatal data give support to the suggestion from physical evidence, that atmospheric CO2 concentrations fell form an Early Devonian high of 10-12 times its present value, to one comparable to the present day by the end of the Carboniferous. These results suggest that stomatal density of fossil leaves has potential value for assessing changes in atmospheric CO2 concentration through geological time. GEOGRAPHIC REGION: Global PERIOD OF RECORD: Lower Devonian to early Permian, ~400 - 280 MMYrBP, plus modern NLE's FUNDING SOURCE: NERC studentship. DESCRIPTION: Paleobotanical (stomatal density and stomatal index) data and reconstruction of atmospheric CO2 concentration for parts of the Paleozoic, and stomatal data for nearest living equivalent (NLE) species. DATA: Table 3. Stomatal density per area, density per volume and index data. Column 1: Species Column 2: Age Column 3: Stomatal density (mm2) mean Column 4: Stomatal density standard deviation Column 5: Number of samples Column 6: Stomatal density standard error Column 7: Stomatal density per volume (mm3) Column 8: Stomatal index mean Column 9: Stomatal index standard deviation Column 10: Number of samples Column 11: Stomatal index standard error Column 12: RCO2 Stomatal Density (mm2) Stomatal Dens. Stomatal Index Species Age Mean s.d. n s.e. (by vol., mm3) Mean s.d. n s.e. RCO2 Aglaophyton major (Kid. and Lang) Lower Devonian 4.5 3.9 n=23 0.82 3.0 2.26 1.1 n=19 0.25 12 Sawdonia ornata (Daws.) Hueber Lower Devonian 4.3 1.9 n=38 0.32 3.6 3.05 1.0 n=13 0.28 12 Juncus effusus L. Recent 309.1 72.8 n=50 10.3 416.2 12.4 2.3 n=50 0.4 1 Psilotum nudum (L.) Beauv. Recent 40.1 16.8 n=145 1.4 89.7 15.5 5.6 n=92 0.6 1 Swillingtonia denticulata Scott and Chal. Carboniferous 787.8 158.9 n=18 37.5 n/a 19.7 4.3 n=14 1.16 1.5 Lebachia frondosa (Renault) Florin Early Permian 309.0 56.5 n=20 12.64 n/a 14.6 2.0 n=20 0.45 1.5 Araucaria heterophylla (Salis.) Franco. Recent 140.7 26.7 n=50 3.78 n/a 11.5 4.2 n=20 0.93 1