Letters to Nature

Nature 413, 622-625 (11 October 2001) | doi:10.1038/35098065; Received 30 April 2001; Accepted 16 August 2001

Acclimatization of soil respiration to warming in a tall grass prairie

Yiqi Luo, Shiqiang Wan, Dafeng Hui & Linda L. Wallace

  1. Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma 73019, USA

Correspondence to: Yiqi Luo Correspondence and requests for materials should be addressed to Y.L. (e-mail: Email: yluo@ou.edu).

The latest report by the Intergovernmental Panel on Climate Change (IPCC) predicts a 1.4–5.8 °C average increase in the global surface temperature over the period 1990 to 2100 (ref. 1). These estimates of future warming are greater than earlier projections, which is partly due to incorporation of a positive feedback. This feedback results from further release of greenhouse gases from terrestrial ecosystems in response to climatic warming2, 3, 4. The feedback mechanism is usually based on the assumption that observed sensitivity of soil respiration to temperature under current climate conditions would hold in a warmer climate5. However, this assumption has not been carefully examined. We have therefore conducted an experiment in a tall grass prairie ecosystem in the US Great Plains to study the response of soil respiration (the sum of root and heterotrophic respiration) to artificial warming of about 2 °C. Our observations indicate that the temperature sensitivity of soil respiration decreases—or acclimatizes—under warming and that the acclimatization is greater at high temperatures. This acclimatization of soil respiration to warming may therefore weaken the positive feedback between the terrestrial carbon cycle and climate.