Abstract Detail

Paleobotanical Section

Stults, Debra [1], Axsmith, Brian [2], Wagner-Cremer, Friederike [3].

Atmospheric paleo-CO₂ estimates based on Taxodium distichum (Cupressaceae) fossils from the Miocene and Pliocene of Eastern North America.

The extant cupressaceous conifer species, Taxodium distichum, has a record from the Late Miocene Brandywine Formation of Maryland and the Late Pliocene Citronelle Formation of southern Alabama based on the gross morphology of fossil leafy shoots, isolated leaves, pollen cones,isolated seed cone scales, and seeds. This determination is now corroborated by the presence of a species-specific arrangement of stomatal bands (narrow adaxial and wide abaxial bands) on preserved leaf cuticles from both formations. A calibration curve constructed from stomatal densities of modern leaves of T. distichum that were collected over the last century of anthropogenic CO₂ increase has been produced. The stomatal density of fossil leaf cuticles from the Brandywine Formation and Citronelle Formation have been directly compared to this curve and produced paleo-CO₂ mean estimates of 360 and 351 ppmv, respectively. Although the temporal resolution of the fossil sites is somewhat low, these results are in general agreement with multiple independent proxies, and demonstrate the utility of T. distichum leaves as instruments for stomatal frequency analysis. It also shows the reliability of stomatal frequency as an important terrestrial proxy for Neogene paleo-CO₂ estimates.

Broader Impacts:

1 - University of South Alabama, Marine Sciences, Life Sciences Building 124, Mobile, AL, 36688, United States
2 - University Of South Alabama, Department Of Biological Sciences, LSCB 124, MOBILE, AL, 36688-0002, USA
3 - Utrecht University, Department of Palaeoecology, Utrecht, the Netherlands

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Sections
Session: 47
Location: Forsyth Room/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 1:30 PM
Number: 47001
Abstract ID:234