|| 要旨トップ | 目次 |||日本生態学会第59回全国大会 (2012年3月，大津) 講演要旨
一般講演（ポスター発表） P3-278A (Poster presentation)
Fluxes and concentrations of CO2 isotope compositions provide information about not only carbon balance but also ecosystem physiological processes and their response to environmental variation. Continuous measurement of 13CO2 over various time-scales (diurnal, daily, seasonal..) using a tunable diode laser spectrometer (TDLS) help us to assess the impact of environmental variability on plant metabolism and water relations.
For testing the performance of a TDLS (G2101-i, Picarro Inc.), we measured the air from two different CO2 concentration cylinders and then analyze Allan's variance. The Allan standard deviations of δ13C for integration time of 500 seconds were 0.22‰ (389ppm CO2) and 0.09‰ (715ppm CO2). Using this TDLS, we continuously measured the concentrations of 12CO2 and 13CO2 inside the automated closed dynamic soil chambers and the surrounding atmosphere of a cool-temperate coniferous forest on the northern slope of Mount Fuji in Japan (AsiaFlux site code:FJY). The δ13C values of the atmospheric CO2 were fluctuated according to the changes of CO2 concentration. Fluctuations of the carbon isotope signal from soil respired CO2(δ13CRs) was not detected, although Keeling plots to estimate δ13CRs were very sensitive and the results were scattered.