Modelling temperature acclimation effects on the carbon dynamics of forest ecosystems in the conterminous United States

Abstract

A B S T R A C TThe projected rise in temperature in the 21st century will alter forest ecosystem functioning and carbon dynamics. To date, the acclimation of plant photosynthesis to rising temperature has not been adequately considered in earth system models. Here we present a study on regional ecosystem carbon dynamics under future climate scenarios incorporating temperature acclimation effects into a large-scale ecosystem model, the terrestrial ecosystem model (TEM). We first incorporate a general formulation of the temperature acclimation of plant photosynthesis into TEM, and then apply the revised model to the forest ecosystems of the conterminous United States for the 21st century under the future Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) climate scenarios A1FI, A2, B1 and B2. We find that there are significant differences between the estimates of carbon dynamics from the previous and the revised models. The largest differences occur under the A1FI scenario, in which the model that considers acclimation effects predicts that the region will act as a carbon sink, and that cumulative carbon in the 21st century will be 35 Pg C higher than the estimates from the model that does not consider acclimation effects. Our results further indicate that in the region there are spatially different responses to temperature acclimation effects. This study suggests that terrestrial ecosystem models should take temperature acclimation effects into account so as to more accurately quantify ecosystem carbon dynamics at regional scales.

Large sensitivity in land carbon storage due to geographical and temporal variation in the thermal response of photosynthetic capacity

“…Our results are in agreement with the modelling study by Chen & Zhuang () on forest ecosystems in the US. Using an adaptation of the KK07 algorithms in the terrestrial ecosystem model (TEM), which does not incorporate modifications of the J max to V cmax (J : V) ratio with T growth , these authors obtained increased C uptake in the temperate region but a decrease in the boreal region under future climate conditions.…”

Trait‐based scaling of temperature‐dependent foliar respiration in a species‐rich tropical forest canopy

“…Ziehn et al . ; Chen & Zhuang ; Wythers, Reich & Bradford ). While it may be appropriate to expect the Q 10 to decrease in relation to the measurement temperature within a given plant, or plants within a given climatic region (as originally suggested by Tjoelker, Oleksyn & Reich ), using this trend to estimate NPP of tropical vegetation in a global model, would result in considerable underestimation of Q 10 compared to our data.…”

“…Because Q 10 has been observed to decline with rising temperature interval over which R is measured (Tjoelker, Oleksyn & Reich 2001;Atkin & Tjoelker 2003), a negative temperature-dependent Q 10 has been incorporated in some global vegetation and ecosystem models (e.g. Ziehn et al 2011;Chen & Zhuang 2013;Wythers, Reich & Bradford 2013). While it may be appropriate to expect the Q 10 to decrease in relation to the measurement temperature within a given plant, or plants within a given climatic region (as originally suggested by Tjoelker, Oleksyn & Reich 2001), using this trend to estimate NPP of tropical vegetation in a global model, would result in considerable underestimation of Q 10 compared to our data.…”

Evaluating aerosol direct radiative effects on global terrestrial ecosystem carbon dynamics from 2003 to 2010

“…The structure of iTem combines the advantage of the Land Surface Model 1.0 (Bonan, 1996), the Terrestrial Ecosystem Model (TEM) (Raich et al, 1991;McGuire et al, 1992McGuire et al, , 1993Zhuang et al, 2003;Lu and Zhuang, 2010;Chen et al, 2011;Chen and Zhuang, 2012;Lu et al, 2013), and incorporates acclimating temperature response of key biogeochemical processes such as photosynthesis and plant respiration (Kattge and Knorr, 2007;Ziehn et al, 2011;Chen and Zhuang, 2013). In iTem, the canopy is particularly modelled in a one-layer, two-big-leaf approach (Dai et al, 2004), which diagnoses energy budget, leaf temperature and photosynthesis separately for sunlit and shaded leaves.…”