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

The effects of elevated atmospheric CO2 on fine root decomposition over a 8 28-day period were investigated using open top chambers with both ambient a nd elevated (700 ppm) CO2 treatments in an oak-palmetto scrub ecosystem at Kennedy Space Center, Florida. Carbon dioxide enrichment of the chambers be gan 15 May 1996. The experiment included roots grown in ambient and elevate d carbon dioxide. Vertical litterbags installed in September 1996 in each e levated and ambient chamber incubated from December 1996 to December 1998 s howed no significant treatment effect on fine root or rhizome mass loss. In itial 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 pe riod of nitrogen immobilization occurred in both fine roots and rhizomes' i n the elevated CO2 incubation, which is a potential mechanism for nitrogen conservation for this system in an elevated CO2 world.