Effects of elevated atmospheric CO2 on fungal competition and decomposition of Fraxinus excelsior litter in laboratory microcosms

Evidence that chemical changes in litter exposed to elevated CO2 might alte r the composition and function of fungal communities in soil is presented. Some potential effects of elevated atmospheric CO2 on the decomposition of Fraxinus excelsior leaf litter and the interactions of the colonizing fungi , growing singly or in simple associations in microcosms, were investigated . Fungal colonization was monitored by analysis of the ergosterol content o f litter and specific PCR-amplified ribosomal DNA spacer products. After < 42 d, fungal colonization was less on litter with a higher C:N ratio when o btained from seedlings grown in elevated CO2 (600 ppm). After triple-specie s inoculation percentage a-cellulose and, in some combinations, nitrogen co ntent was reduced on litter from seedlings grown in elevated CO2.