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Effects of elevated atmospheric CO2 on root decomposition in a scrub oak ecosystem


Frank P. Day, fax +1/757-683-5283, e-mail


The effects of elevated atmospheric CO2 on fine root decomposition over a 828-day period were investigated using open top chambers with both ambient and elevated (700 ppm) CO2 treatments in an oak–palmetto scrub ecosystem at Kennedy Space Center, Florida. Carbon dioxide enrichment of the chambers began 15 May 1996. The experiment included roots grown in ambient and elevated carbon dioxide. Vertical litterbags installed in September 1996 in each elevated and ambient chamber incubated from December 1996 to December 1998 showed no significant treatment effect on fine root or rhizome mass loss. Initial fine root percentage mass loss varied from 10.3% to 13.5% after three months; 55.5% to 38.3% of original mass had been lost after 828 days. A period of nitrogen immobilization occurred in both fine roots and rhizomes in the elevated CO2 incubation, which is a potential mechanism for nitrogen conservation for this system in an elevated CO2 world.