Treatment effects on ecosystem CO2 fluxes.

Ecosystem photosynthesis (Peco) and respiration (Reco) were measured at the Prairie Heating and CO2 Enrichment Experiment during 2006–2010, and are presented as response ratios. Data reflect ratios of a given treatment relative to ambient conditions and are based on cumulative growing season fluxes. Irrigation effects are shown in italics. Statistically significant differences (P2], and Elevated [CO2]×Warming) and the ambient treatment within a given year are indicated by an asterisk (*). Significant differences (P2] effects are indicated by (§).