Ecological Research

, Volume 30, Issue 2, pp 311–325

Contribution of soil moisture to seasonal and annual variations of soil CO2 efflux in a humid cool-temperate oak-birch forest in central Japan

  • Ayaka Wenhong Kishimoto-Mo
  • Seiichiro Yonemura
  • Masaki Uchida
  • Miyuki Kondo
  • Shohei Murayama
  • Hiroshi Koizumi
Special Feature Long-term and interdisciplinary research on forest ecosystem functions: Challenges at Takayama site since 1993

DOI: 10.1007/s11284-015-1254-6

Cite this article as:
Kishimoto-Mo, A.W., Yonemura, S., Uchida, M. et al. Ecol Res (2015) 30: 311. doi:10.1007/s11284-015-1254-6

Abstract

To quantify the contribution of soil moisture to seasonal and annual variations in soil CO2 efflux in a cool-humid deciduous broadleaf forest, we measured soil CO2 efflux during the snow-free seasons of 2005–2008 using an automated chamber technique. This worked much better than manual chambers employing the same steady-state through-flow method. Soil CO2 efflux (g C m−2 period−1) during the snow-free season ranged from 979.8 ± 49.0 in 2005 to 1131.2 ± 56.6 in 2008 with a coefficient variation of 6.4 % among the 4 years. We established two-parameter (soil temperature and moisture) empirical models, finding that while soil temperature and moisture explained 69–86 % and 10–13 % of the temporal variability, respectively. Soil moisture had the effect of modifying the temporal variability of soil CO2 efflux, particularly during summer and early fall after episodic rainfall events; greater soil moisture enhanced soil CO2 efflux in the surface soil layers. High soil moisture conditions did not suppress soil CO2 efflux, leading to a positive correlation between normalized soil CO2 efflux (ratio of the measured to predicted efflux using a temperature-dependent Q10 function) and soil moisture. Therefore, enhanced daily soil CO2 efflux following heavy rainfall events could significantly reduce net ecosystem exchange (i.e. daily net ecosystem production) by 32 % on some days. Our results highlight the importance of precisely estimating the response of soil CO2 efflux to changes in soil moisture following rainfall events when modeling seasonal carbon dynamics in response to climate change, even in humid monsoon regions.

Keywords

Automated soil respiration chambers Empirical model Open-flow IRGA method Rainfall Soil respiration 

Supplementary material

11284_2015_1254_MOESM1_ESM.eps (5.3 mb)
Fig. S1 Daily trends in hourly soil CO2 efflux measured with AOCC and manual (Rs_Manual) chambers in different seasons in 2005. (a) 1–10 June, (b) 1–10 August, (c) 21–30 August, and (d) 26 October to 4 November (EPS 5461 kb)
11284_2015_1254_MOESM2_ESM.eps (574 kb)
Fig. S2 Changes in (a) daily mean air (at 27 m) and soil temperature (1 cm), (b) daily rainfall and volume soil water content, and (c) mean daily soil CO2 efflux (Rs) and (net ecosystem CO2 exchange [NEE] based on tower eddy covariance) during the rainy season in 2005 (15 June to 15 July). Error bars of measured soil CO2 efflux represent the standard deviation of four AOCC chambers. We hypothesized that following heavy rainfall events during 27 June to 4 July, the reduction in NEE could be estimated as the changes from the base line (Δ NEE, 40.3 g C m−2). Similarly, the enhancement of soil CO2 efflux (Rs) could be estimated as the changes from the base line (Δ Rs, 12.8 g C m−2). Thus, as a crude estimation, the enhanced Rs may contribute to the 32 % reduction in NEE (Δ Rs/Δ NEE × 100 %) (EPS 573 kb)

Copyright information

© The Ecological Society of Japan 2015

Authors and Affiliations

  • Ayaka Wenhong Kishimoto-Mo
    • 1
  • Seiichiro Yonemura
    • 1
  • Masaki Uchida
    • 2
    • 3
  • Miyuki Kondo
    • 4
  • Shohei Murayama
    • 5
  • Hiroshi Koizumi
    • 6
  1. 1.National Institute for Agro-Environmental Sciences (NIAES)TsukubaJapan
  2. 2.National Institute of Polar Research (NIPR)TachikawaJapan
  3. 3.SOKENDAI (The Graduate University for Advanced Studies)TachikawaJapan
  4. 4.National Institute for Environmental Studies (NIES)TsukubaJapan
  5. 5.National Institute of Advanced Industrial Science and Technology (AIST)TsukubaJapan
  6. 6.Laboratory for Environmental EcologyWaseda UniversityTokyoJapan

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