MINIATURIZED METHOD TO MEASURE CARBON-DIOXIDE PRODUCTION AND BIOMASS OF SOIL-MICROORGANISMS

Microbial activities and biomasses in soils exhibit steep gradients across short distances, forming microhabitats with different qualities. A methodological study was carried out to determine CO2 production of soil microorganisms in miniature. Soil samples (2-4 g) from 28 different soil types of southern Germany were incubated directly in a small glass ampoule within a 20-mL gas-tight syringe. A high correlation (r = 0.96) between CO2 production and heat output suggests that this micromethod is useful for the determination of CO2 respiration and the estimation of microbial biomass of small soil samples.