|Scott, Russell - Russ|
Submitted to: Biogeosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2011
Publication Date: 6/6/2011
Citation: Yuan, W., Luo, Y., Liang, S., Yu, G., Niu, S., Stoy, P., Chen, J., Desai, A., Lindroth, A., Gough, C., Ceulemans, R., Arain, A., Bernhofer, C., Cook, B., Cook, D., Dragoni, D., Gielen, B., Janssens, I., Longdoz, B., Liu, H., Lund, M., Matteucci, G., Moors, E., Scott, R.L., Seufert, G., Varner, R. 2011. Thermal adaptation of net ecosystem exchange. Biogeosciences. 8:1453-1463. Interpretive Summary: Ecosystem plant photosynthesis (carbon dioxide uptake) and respiration (carbon dioxide release) have been shown to adapt to environmental temperature levels where they are located, but much less is known about their interactive effects to temperature changes which influences the net exchange of carbon dioxide between the biosphere and atmosphere. To address this we used a dataset of measured carbon dioxide exchange from 72 sites around the world and constructed temperature response curves for each. We identified the temperatures at which the ecosystems transferred from a carbon source to a sink and temperatures at which carbon uptake was maximized. We found that the former was strongly related to the average annual temperature and the latter was related to the average growing season temperature. There results imply that the ecosystem exchange of carbon dioxide adapts to the temperature where it is located. Investigating the thermal adaptation of ecosystems should improve our ability to predict regional and global carbon balances in the future.
Technical Abstract: Thermal adaptation of gross primary production and ecosystem respiration has been well documented over broad thermal gradients. However, no study has examined their interaction as a function of temperature, i.e. the thermal responses of net ecosystem exchange of carbon (NEE). In this study, we constructed temperature response curves of NEE against temperature using 380 site-years of eddy covariance data at 72 forest, grassland and shrubland ecosystems located at latitudes ranging from ~29 degrees N to 64 degrees N. The response curves were used to define two critical temperatures: transition temperature (Tb) at which ecosystem transfer from carbon source to sink and optimal temperature (To) at which carbon uptake is maximized. Tb was strongly correlated with annual mean air temperature. To was strongly correlated with mean temperature during the net carbon uptake period across the study ecosystems. Our results imply that the net ecosystem exchange of carbon adapts to the temperature across the geographical range due to intrinsic connections between vegetation primary production and ecosystem respiration.