PARENT SESSION
Poster Session #11: Elevated CO₂.
Monday, August 6, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Respiratory carbon loss will increase at elevated atmospheric CO₂: A meta-analysis.

Wang, Xianzhong¹, Curtis, Peter², Griffin, Kevin¹, ^{1 2}

ABSTRACT- Terrestrial plants respire as much as 60 gigatons of carbon annually, or nearly 50% of global photosynthetic fixation. Most studies of plant respiration have found a reduction of instantaneous respiration at elevated atmospheric CO2, although enhancement of respiration has also been observed. To construct the global carbon budget in a higher CO₂ environment, the total amount of carbon lost through plant respiration is more important than the more commonly reported instantaneous respiratory rate, typically expressed on a per unit biomass basis. We conducted a meta-analysis to estimate the amount of carbon loss through plant respiration from terrestrial ecosystems as affected by atmospheric CO₂. We found that despite decreases in the instantaneous rate of respiration, elevated CO₂ significantly increased the amount of respiratory carbon loss at the whole plant level. The magnitude of increase was larger in herbaceous than in woody species. Additionally, when plants were environmentally stressed, which is common in natural ecosystems, respiratory carbon loss tended to increase compared with non-stressed plants. An analysis of ecosystem-level studies also showed a positive effect of elevated CO₂ on respiratory carbon loss.

KEY WORDS: elevated CO₂, meta-analysis, plant respiration