A global relationship between the heterotrophic and autotrophic components of soil respiration?

Authors

  • Ben Bond-Lamberty,

    1. Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
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  • Chuankuan Wang,

    1. Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
    2. Ecology Program, Northeast Forestry University, Harbin 150040, China
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  • Stith T. Gower

    1. Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
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Ben Bond-Lamberty, tel. +1 608 262 6369, fax +1 608 262 9922, e-mail: bpbond@wisc.edu

Abstract

Soil surface CO2 flux (RS) is overwhelmingly the product of respiration by roots (autotrophic respiration, RA) and soil organisms (heterotrophic respiration, RH). Many studies have attempted to partition RS into these two components, with highly variable results. This study analyzes published data encompassing 54 forest sites and shows that RA and RH are each strongly (R2>0.8) correlated to annual RS across a wide range of forest ecosystems. Monte Carlo simulation showed that these correlations were significantly stronger than any correlation introduced as an artefact of measurement method. Biome type, measurement method, mean annual temperature, soil drainage, and leaf habit were not significant. For sites with available data, there was a significant (R2=0.56) correlation between total detritus input and RH, while RA was unrelated to net primary production. We discuss why RA and RH might be related to each other on large scales, as both ultimately depend on forest carbon balance and photosynthate supply. Limited data suggest that these or similar relationships have broad applicability in other ecosystem types. Site-specific measurements are always more desirable than the application of inferred broad relationships, but belowground measurements are difficult and expensive, while measuring RS is straightforward and commonly done. Thus the relationships presented here provide a useful method that can help constrain estimates of terrestrial carbon budgets.

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