On the variability of respiration in terrestrial ecosystems: moving beyond Q10

Global Change Biology - Tập 12 Số 2 - Trang 154-164 - 2006
Eric A. Davidson1, Ivan A. Janssens2, Yiqi Luo3
1The Woods Hole Research Center, PO Box 296, Woods Hole, MA 02543, USA
2Department of Biology, University Instelling Antwerp, B‐2610 Wilrijk, Belgium,
3Department of Botany and Microbiology, University of Oklahoma, 770 Van Vleet Oval, Norman, OK 73019, USA

Tóm tắt

Abstract

Respiration, which is the second most important carbon flux in ecosystems following gross primary productivity, is typically represented in biogeochemical models by simple temperature dependence equations. These equations were established in the 19th century and have been modified very little since then. Recent applications of these equations to data on soil respiration have produced highly variable apparent temperature sensitivities. This paper searches for reasons for this variability, ranging from biochemical reactions to ecosystem‐scale substrate supply. For a simple membrane‐bound enzymatic system that follows Michaelis–Menten kinetics, the temperature sensitivities of maximum enzyme activity (Vmax) and the half‐saturation constant that reflects the affinity of the enzyme for the substrate (Km) can cancel each other to produce no net temperature dependence of the enzyme. Alternatively, when diffusion of substrates covaries with temperature, then the combined temperature sensitivity can be higher than that of each individual process. We also present examples to show that soluble carbon substrate supply is likely to be important at scales ranging from transport across membranes, diffusion through soil water films, allocation to aboveground and belowground plant tissues, phenological patterns of carbon allocation and growth, and intersite differences in productivity. Robust models of soil respiration will require that the direct effects of substrate supply, temperature, and desiccation stress be separated from the indirect effects of temperature and soil water content on substrate diffusion and availability. We speculate that apparent Q10 values of respiration that are significantly above about 2.5 probably indicate that some unidentified process of substrate supply is confounded with observed temperature variation.

Từ khóa


Tài liệu tham khảo

Aber JD, 1991, Terrestrial Ecosystems

10.1006/anbo.2000.1175

10.1515/zpch-1889-0116

10.1016/S1360-1385(03)00136-5

10.1046/j.1365-2486.2003.00692.x

10.1126/science.1062962

10.1007/978-3-642-68090-8_11

10.1007/BF01343734

10.1038/25119

10.2136/sssaj2003.1888

Borken W, 2005, Effects of experimental drought on soil respiration and radiocarbon efflux from a temperate forest soil, Global Change Biology

10.1046/j.1365-2486.2002.00547.x

10.1016/0038-0717(85)90070-7

10.1038/35041539

10.1023/A:1004417419288

10.1111/j.1529-8817.2003.00727.x

10.1093/treephys/23.18.1263

10.1046/j.1365-2486.1998.00128.x

Davidson EA, 2005, A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce‐dominated forest, Global Change Biology

10.1038/35048672

10.1023/A:1006204113917

10.1051/forest:19990304

10.1051/forest:19990403

10.1038/nature03138

10.1007/BF00386231

10.1038/35009076

10.1126/science.279.5348.214

10.2136/sssaj1994.03615995005800060015x

10.1029/2003GB002119

10.1023/A:1006244819642

10.1007/978-1-4613-0021-2_10

10.1093/treephys/13.1.1

Harris RF, 1981, Water Potential Relations in Soil Microbiology. Soil Science Society of America Special Publications Number 9, 23

10.1007/s10533-004-2946-0

10.1038/35081058

10.1111/j.1365-2486.2004.00847.x

10.1046/j.1365-2486.1999.00281.x

10.1029/97GB02729

10.1093/treephys/23.7.433

10.1007/978-3-662-05171-9_12

10.1046/j.1365-2486.2001.00412.x

Janssens IA, 1999, Forest Ecosystem Modelling, Upscaling and Remote Sensing, 19

10.1046/j.1365-2486.2003.00636.x

10.1016/0038-0717(87)90070-8

10.1016/0038-0717(94)00242-S

10.1023/A:1006238902976

10.1038/nature03226

10.2136/sssaj1984.03615995004800060013x

10.1023/A:1015744126533

10.2307/2389824

Michaelis L, 1913, Die kinetik der invertin wirkung, Biochemisches Zeitschrift, 49, 334

Papendick RI, 1981, Water Potential Relations in Soil Microbiology. Soil Science Society of America Special Publications Number 9, 1

Prentice IC, 2001, Climate Change 2001: The Scientific Basis, 183

10.2136/sssaj2003.4020

10.1029/94GB02723

10.1029/2003GB002035

10.1046/j.1365-2486.2002.00530.x

10.1046/j.1365-2486.2002.00521.x

Rolston DE, 2002, Method of Soil Analysis, Part 4 Physical Methods. Soil Science Society of America Number 5, 1113

10.1126/science.1091165

10.1029/1999GB001248

10.1093/jxb/erg121

10.1139/x85-018

Schleser GH, 1982, The response of CO2 evolution from soils to global temperature changes, Zeitschrift fur Naturforschung, 37, 287, 10.1515/zna-1982-0316

10.2136/sssaj1990.03615995005400060018x

Swift MJ, 1979, Decomposition in terrestrial ecosystems

10.1038/35009084

Hoff JH, 1898, Lectures on Theoretical and Physical Chemistry. Part 1. Chemical Dynamics

10.1111/j.1529-8817.2003.00744.x

10.1029/2002GB001971

10.1016/0038-0717(75)90052-8

10.1046/j.1354-1013.2001.00435.x

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Global Change Biology

Tập 12 Số 2

154-164

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