HR: 13:55h
AN: B13B-02    [Abstracts]
TI: Quantification of Isotopic Fractionation of Atmospheric Carbon Dioxide by Terrestrial Photosynthesis Using the Carbon Isotopic Composition of Plant Wax Aerosols
AU: * Conte, M H
B13B-02 AF: Ecosystems Center Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 20543 United States
AU: * Conte, M H
B13B-02 AF: Bermuda Biological Station for Research, Inc., Ferry reach, St. Georges, GE01 Bermuda
AU: Weber, J C
EM: jweber@mbl.edu
AF: Ecosystems Center Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 20543 United States
AB: The concentration and carbon isotopic composition of atmospheric CO₂ can be used to partition terrestrial and ocean carbon sinks because terrestrial photosynthesis strongly discriminates against ¹³C whereas discrimination during ocean uptake is negligible. This approach, though powerful, depends upon the accurate knowledge of the temporal and large spatial scale variation in terrestrial photosynthetic discrimination (Δ), a formidable challenge due to heterogeneity of terrestrial ecosystems. Previous studies have indicated that the isotopic composition of plant leaf wax aerosols record Δ over large regional spatial scales and at ~monthly resolution. Recent studies have focused upon the processes that link carbon isotopic discrimination at the ecosystem scale with the isotopic composition of plant wax aerosols in the atmospheric boundary layer. In this presentation we will synthesize results from "groundtruthing" studies of terrestrial ecosystems [Alaska (tundra), Italy (hardwood beech forest), Florida (slash pine forest), Maine (transitional boreal forest), and Alberta (northern prairie)] and from sampling continental air masses at remote island stations (Bermuda, Barbados). These data provide further evidence that wax isotopic composition faithfully tracks changes in plant discrimination and that ablated waxes in continental air masses reflect the weighted Δ of the source ecosystems.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0420 Biomolecular and chemical tracers
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
SC: Biogeosciences [B]
MN: Fall Meeting 2005