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Soil CO 2 efflux in a tropical forest in the central Amazon
Author(s) -
Doff sotta Eleneide,
Meir Patrick,
Malhi Yadvinder,
Donato nobre Antonio,
Hodnett Martin,
Grace John
Publication year - 2004
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1529-8817.2003.00761.x
Subject(s) - efflux , carbon cycle , water content , environmental science , diel vertical migration , carbon dioxide , soil respiration , soil carbon , environmental chemistry , flux (metallurgy) , chemistry , soil science , hydrology (agriculture) , soil water , ecology , ecosystem , biology , geology , biochemistry , geotechnical engineering , organic chemistry
This study investigated the spatial and temporal variation in soil carbon dioxide (CO 2 ) efflux and its relationship with soil temperature, soil moisture and rainfall in a forest near Manaus, Amazonas, Brazil. The mean rate of efflux was 6.45±0.25 SE μmol CO 2 m −2 s −1 at 25.6±0.22 SE°C (5 cm depth) ranging from 4.35 to 9.76 μmol CO 2 m −2 s −1 ; diel changes in efflux were correlated with soil temperature ( r 2 =0.60). However, the efflux response to the diel cycle in temperature was not always a clear exponential function. During period of low soil water content, temperature in deeper layers had a better relationship with CO 2 efflux than with the temperature nearer the soil surface. Soil water content may limit CO 2 production during the drying‐down period that appeared to be an important factor controlling the efflux rate ( r 2 =0.39). On the other hand, during the rewetting period microbial activity may be the main controlling factor, which may quickly induce very high rates of efflux. The CO 2 flux chamber was adapted to mimic the effects of rainfall on soil CO 2 efflux and the results showed that efflux rates reduced 30% immediately after a rainfall event. Measurements of the CO 2 concentration gradient in the soil profile showed a buildup in the concentration of CO 2 after rain on the top soil. This higher CO 2 concentration developed shortly after rainfall when the soil pores in the upper layers were filled with water, which created a barrier for gas exchange between the soil and the atmosphere.