Yi, C., R. Li, P.S. Bakwin, A.R. Desai, D.M. Ricciuto, S. Burns, A. Turnipseed, S.C. Wofsy, J.W. Munger, K. Wilson, and R.K. Monson, 2004. A nonparametric method for separating photosynthesis and respiration components in CO2 flux measurements, Geophysical Research Letters, 31 (L17107), (doi:10.1029/2004GL020490).

Future climate change is expected to affect ecosystem-atmosphere CO2 exchange, particularly through the influence of temperature on photosynthesis and respiratory processes. To date, however, few studies have shown that differences in the response of NEE to temperature among ecosystems can be explained by differences in photosynthetic and respiratory processes. Using a new nonparametric statistical model, we analyzed the net ecosystem CO2 exchange (NEE) data from four forest ecosystems. We observed that differences among forests in their ability to assimilate CO2 as a function of temperature were attributable to consistent differences in the temperature dependence of the photosynthetic and respiratory components of NEE. This observation provides empirical validation of efforts to develop models of NEE from the first-principle relationships between photosynthetic and respiratory processes and climate. Our results also showed that models of seasonal dynamics in NEE that lack specific consideration of the temperature dependence of respiration and photosynthesis are likely to carry significant uncertainties.