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Respiration in Boreal Forest Soil as Determined from Carbon Dioxide Concentration Profile
Author(s) -
Pumpanen Jukka,
Ilvesniemi Hannu,
Kulmala Liisa,
Siivola Erkki,
Laakso Heikki,
Kolari Pasi,
Helenelund Christer,
Laakso Mikko,
Uusimaa Maria,
Hari Pertti
Publication year - 2008
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0199
Subject(s) - soil respiration , respiration , carbon dioxide , soil horizon , ecosystem respiration , carbon cycle , humus , chemistry , taiga , soil carbon , environmental science , ecosystem , environmental chemistry , zoology , soil science , soil water , botany , ecology , biology , primary production , organic chemistry
Soil respiration forms a substantial part of the ecosystem respiration. However, the respiration measurements conducted with chambers on the soil surface do not give information on the vertical distribution of CO 2 sources and its seasonal dynamics. We used permanently installed CO 2 probes to determine the CO 2 profile in a boreal coniferous forest soil and calculated the CO 2 efflux from the concentration profile with a dynamic model. There was an increase in both soil CO 2 efflux and soil air CO 2 concentration over the 2.5‐mo study period between April 15 and June 30. The CO 2 efflux determined from the concentration profile was in relatively good agreement with the CO 2 efflux measured by open dynamic chamber method. We also determined the respiration of different soil horizons and estimated the contribution of recent photosynthate to total respiration. Humus layer and A‐horizon contributed 69.9%, B‐horizon 19.8%, and C‐horizon 10.4% of the total CO 2 efflux. The Q 10 values determined over 7‐d periods were on average 2.54, 3.66, and 13.14 in A‐, B‐, and C‐horizons, respectively. However, when fitted over the whole 2.5‐mo time period, the Q 10 values were 3.56, 5.57, and 17.45 in A‐, B‐, and C‐horizons, respectively. Based on the different temperature responses obtained over 7‐d and 2.5‐mo time periods, we estimated the contribution of recent photosynthate to soil respiration. In April, the respiration originating from recent photosynthate contributed about 2% of the total respiration in the A‐, B‐, and C‐horizons and increased to 32, 35, and 24% by June 30 in the respective soil horizons.