PARENT SESSION
Poster Session # 15: Plant Ecology.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Effect of elevated CO2 concentration on soil respiration and above and belowground biomass productivity.
Kudeyarov, V1, 2, Bil, K*,1, 2, Semenov, V1, Blagodatskii, S1, Murthy, R2, Barron-Gafford, G2, Demyanova, E1, Handley, L2, 1 Russian Academy of Science, Puschino, Russia2 Biosphere 2 Center, Oracle, AZ, USA
ABSTRACT- Above and below ground biomass of a coppice cottonwood (Populus deltoides Bartr.) tree system grown under 40, 80, and 120 Pa CO2 was excavated after 3 years of growth in the Intensive Forestry Mesocosm at the Biosphere 2 Center. Soil respiration at natural moisture level was rather low and did not differ significantly between plots with different levels of atmospheric CO2. This may be attributed to the variability of soil moisture content. Soil respiration at the optimal moisture conditions (basal respiration) for the 120 Pa CO2 was significantly higher than for the 80 or 40 Pa CO2. The same relationship was found for substrate-induced respiration (SIR). The greatest increase in respiration induced by moistening was observed for 120 Pa CO2. The 120 Pa mesocosm also had the highest microbial biomass. Results reveal that respiration activity of soil and microbial biomass in the 120 Pa mesocosm were higher than in the other two mesocosms. Total tree biomass (above+belowground) between the 40 and 80 Pa CO2 mesocosms was significantly different.
Key words: Biosphere 2 Center