Article

Abstract

-The CO 2 fluxes from the forest floor were measured using a closed chamber method at 26 sites from 26 • N Lat. to 44 • N Lat. in Japan. Seasonal fluctuation in CO 2 flux was found to correlate exponentially with seasonal fluctuation in soil temperature at each site. Estimate of annual carbon emission from the forest floor ranged from 3.1 to 10.6 Mg C ha −1 . The emission rate of soil-organic-carbon-derived CO 2 , obtained by incubation of intact soil samples, correlated closely with the carboxymethylcellulase (CMCase) activity in the soil. The sum of cool-water soluble polysaccharides, hot-water soluble polysaccharides, hemicellulose, and cellulose content in the soil was greater at the sites with low CMCase activity than that at the sites with high CMCase activity. Because the sites in cooler-climate sites had a high content of easily decomposable soil organic carbon and organic litter, the potential increase in CO 2 efflux from forest floor with increasing soil temperature would be greater in cooler-climate sites.cellulose / Japanese forest / soil organic carbon / soil respiration Résumé -Fort potentiel d'accroissement de flux de CO 2 issu de la surface du sol forestier en relation avec le réchauffement global dans les régions fraîches du Japon. Le flux de CO 2 issu du sol forestier a été mesuré dans 26 sites, allant du 26 • au 44 • de latitude Nord dans l'archipel japonais, en utilisant la méthode des chambres fermées. Il a pu être mis en évidence que la fluctuation saisonnière du flux de CO 2 était corrélée de façon exponentielle avec celle de la température du sol de chacun des sites étudiés. L'estimation annelle de l'émission de carbone venant du sol variait de 3,1 à 10,6 Mg C ha −1 . Le taux d'émission de CO 2 obtenu par incubation d'échantillons intacts de sol est corrélé positivement avec l'activité de la carboxyméthacellulase (CMCase), dans le sol. La somme totale des polysaccharides solubles dans l'eau froide, des polysaccharides solubles dans l'eau chaude, des hémicelluloses et de la cellulose contenus dans le sol était plus grande dans les sites caractérisés par une faible activité CMCase que dans les sites avec une forte activité CMCase. Du fait que les sites en climat frais ont un contenu élevé en carbone organique du sol facilement décomposable et une litière organique, le potentiel d'accroissement du flux de CO 2 avec l'accroissement de la température du sol devrait être plus grand dans les sites à climat frais.cellulose / forêt japonaise / carbone organique du sol / respiration du sol

Methane uptake rates in Japanese forest soils depend on the oxidation ability of topsoil, with a new estimate for global methane uptake in temperate forest

“…The range of Q 10 value of the CH 4 uptake rate (1.14-2.57) was comparable with the range in previous reports [e.g., 1.3 (Priemé and Christensen 1997), 1.2-2.0 (Crill 1991) and 1.5 (Born et al 1990)]. The average Q 10 value (1.51) was about a half of the Q 10 value of (Ishizuka et al 2006). In the ambient air, the CH 4 concentration was too low to become saturated in CH 4 consumption rate and the CH 4 uptake rate was limited by the rate of CH 4 diffusion in the soil rather than enzymatic activity (King and Adamsen 1992).…”

“…The general soil properties are shown in Table 2. Further information, such as soil texture and microbial biomass C in each site, can be found elsewhere (Ishizuka et al 2006). …”

Continuous estimation of winter carbon dioxide efflux from the snow surface in a deciduous broadleaf forest

“…The soil pH was 6.2. Ishizuka et al provided detailed information on the soil [Ishizuka et al, 2006]. It has a cool temperate climate with an annual mean temperature of 7.1°C and an annual precipitation of 957 mm.…”

Impact of plant species, N fertilization and ecosystem engineers on the structure and function of soil microbial communities

“…Furthermore, with approximately 3-5.7 Tg CH 4 yr -1 temperate forest soils represent one of the most important terrestrial sinks for atmospheric CH 4 , (Dutaur and Verchot 2007;Curry 2009;Ishizuka et al 2009). The atmospheric concentration of CH 4 increased over the last 150 years by 248%, from 715 ppb in pre-industrial times to 1774 ppb nowadays (Forster 2007).…”

“…Due to the strong impact of N addition on CH 4 uptake, intensive research in the laboratory and the field has addressed this topic (Goldman et al 1995;Bradford et al 2001bBradford et al , 2001aJang et al 2006;Borken and Brumme 2009;Bodelier 2011b) ) during NH 4 + oxidation (King and Schnell 1994b) and osmotic effects resulting from the formation of salts in the course of fertilisation (Dunfield and Knowles 1995;Gulledge and Schimel 1998). Furthermore, several studies reported a negative effect of oxidised N (NO 3 − ) on the CH 4 oxidation in soil (Priemé and Christensen 1997; Wang and Ineson 2003;Reay and Nedwell 2004;Xu and Inubushi 2004;Ishizuka et al 2009). This inhibiting effect has been explained by (a) the production of toxic concentrations of NO 2 in anaerobic microsites (Adamsen and King 1993;Whalen 2000;Wang and Ineson 2003) or (b) the osmotic effect of salts (Dunfield and Knowles 1995;Gulledge and Schimel 1998).…”