JP1.6

Effect of elevated CO₂ on net ecosystem carbon production in Florida scrub oak during a nine year study

Thomas L. Powell, Smithsonian Environmental Research Center, Kennedy Space Center, Florida; and D. P. Johnson, T. J. Seiler, C. R. Hinkle, and B. G. Drake

The effect of elevated atmospheric CO₂ on net ecosystem carbon production (NEP) of forests has seldom been determined using gas exchange. We used open top chambers to periodically measure NEP of a Florida scrub oak ecosystem exposed to elevated atmospheric CO₂. At the same time, we continuously measured NEP of the ecosystem using a nearby eddy covariance system. A comparison between simultaneous measurements from the eddy covariance system and chambers at normal ambient CO₂ concentrations confirmed that the chambers produced less than a +/-10% difference on gas exchange. We used the chamber data to scale the eddy covariance measurements and compared the results of NEP with the CO₂ effect to the sum of biomass estimates for shoots, roots, and soil carbon measured in the elevated CO₂ chambers. After nine years of CO₂ fumigation, the estimated stimulation of elevated atmospheric CO₂ on NEP was 10.72 tCha^-1 compared to biomass stimulation of 6.36 tCha^-1.

Joint Poster Session 1, Joint Poster Session
Tuesday, 29 April 2008, 3:15 PM-6:00 PM, Floral Ballroom Magnolia

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