Acclimatization of soil respiration to warming in a tall grass prairie

Abstract

The latest report by the Intergovernmental Panel on Climate Change (IPCC) predicts a 1.4-5.8 degrees 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 warming. 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 climate. 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 degrees 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.

Carbon Inputs from Miscanthus Displace Older Soil Organic Carbon Without Inducing Priming

“…This assumed an exponential relationship and applied the 'nls' function (nonlinear least squares) as a part of the base stats package in R to estimate a Q 10 value according to Raich and Potter [63] and Luo et al [64]. This represented the change in respiration rate given a 10°C rise in temperature.…”

CO2 Deficit in Temperate Forest Soils Receiving High Atmospheric N-Deposition

“…Soil warming experiments in Massachusetts (44) and in northern Sweden (45) did not result in the expected increase in CO 2 release from the soil. Acclimatization of soil respiration was suggested to occur under temperature increase.…”

Terrestrial carbon-cycle feedback to climate warming: experimental evidence on plant regulation and impacts of biofuel feedstock harvest

“…Soil C in the warming plus clipping plots would decrease by 1,316 g C m -2 (6 yr) -1 due to the both warming and clipping effects on soil loss. However, soil respiration at our experimental site did not directly respond to warming in 1999 and 2000 (Luo et al 2001) and was stimulated by warming from 2001 to 2005 without clipping (Fig. 2A).…”

“…Experimental warming at our site did not result in instantaneous increases in soil respiration in 1999 and 2000 without clipping (Luo et al 2001; Fig. 2A Warming stimulated heterotrophic respiration by 11% without clipping (P<0.05) and 9% with clipping (P<0.05) ( Table 3).…”