Elevated CO₂ and O₃ alter soil nitrogen transformations beneath trembling aspen, paper birch, and sugar maple

Abstract

Nitrogen cycling in northern temperate forest ecosystems could change under increasing atmospheric CO₂ and tropospheric O₃ as a result of quantitative and qualitative changes in plant litter production. At the Aspen Free Air CO₂-O₃ Enrichment (FACE) experiment, we previously found that greater substrate inputs to soil under elevated CO2 did not alter gross N transformation rates in the first 3 years of the experiment. We hypothesized that greater litter production under elevated CO₂ would eventually cause greater gross N transformation rates and that CO2 effects would be nullified by elevated O₃. Following our original study, we continued measurement of gross N transformation rates for an additional four years.

Citation

Holmes, William E.; Zak, Donald R.; Pregitzer, Kurt S.; King, John S. 2006. Elevated CO2 and O3 alter soil nitrogen transformations beneath trembling aspen, paper birch, and sugar maple. Ecosystems. 9: 1354-1363.