|Paw U, K.|
|Scott, Russell - Russ|
Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2012
Publication Date: 8/1/2012
Citation: Niu, S., Luo, Y., Fei, S., Yuan, W., Zhang, Z., Schimel, D., Amiro, B., Ammann, C., Arain, M.A., Arneth, A., Aubinet, M., Barr, A., Beringer, J., Bernhofer, C., Black, A.T., Buchmann, N., Cescatti, A., Chen, J., Davis, K.J., Delllwik, E., Desai, A.R., Dolman, H., Drake, B.G., Etzold, S., Francois, L., Gianele, D., Goldstein, A., Gu, L., Hanan, N., Helfer, C., Hirano, T., Hollinger, D.Y., Lindroth, A., Janssens, I., Jones, M., Kiely, G., Kolb, T.E., Kutsch, W.L., Lafleur, P., Law, B.E., Litvak, M., Loustau, D., Lund, M., Marek, M., Matteucci, G., Martin, T.A., Montagnani, L., Moors, E., Munger, J.W., Noormets, A., Oechel, W., Olejnik, J., Paw U, K.T., Pilegaard, K., Rambal, S., Saleska, S., Scott, R.L., Seufert, G., Spano, D., Stoy, P., Sutton, M.A., Varlagin, A., Vesala, T., Wohfahrt, G., Yakir, D., Yang, B. 2012. Thermal optimality of net ecosystem exchange of carbon dioxide and underlying mechanisms. New Phytologist. 194(3):775-783. Interpretive Summary: Ecosystems provide multiple services to humans. Models that represent ecosystem functioning, such as the cycling of carbon, are based on relationships with temperature that have been developed for enzyme- or leaf-level processes. The response of the ecosystem in total to changes in temperature, however, is not known. In this paper, data from a large network of carbon dioxide exchange measurement sites are used to see how this net carbon dioxide exchange varies with temperature. It is found that peak uptake of carbon dioxide by an ecosystem is strongly related to a site’s average growing season temperature, which may indicate an adaptation of plants and organisms within an ecosystem to temperature. This finding is a novel property of ecosystems that was unknown prior to this synthesis effort and can be useful for the testing of ecosystem models used to predict the response to global climate change.
Technical Abstract: It has been well established that individual organisms can acclimate and adapt to temperature change to optimize their performance (i.e., achieve thermal optimality). However, whether ecosystems with an assembly of organisms would also undergo thermal optimization has not been examined on a broader basis. Our synthesis of 638 site-years of eddy covariance data shows that the temperature response curves of net ecosystem exchange of carbon dioxide are parabolic, with their thermal optima being strongly correlated with growing season mean temperature across the globe and with the annual mean temperatures over years at individual sites. Ecosystem-level thermal optimality is a newly discovered emergent property with its mechanisms yet to be further understood but has important implications for modeling analysis of ecosystem-climate feedbacks.