关键词: 克隆文库, 空气细菌, 空气真菌, 群落结构, 微生物多样性

Abstract: The CO₂ concentration of Phyllostachys edulis forest ecosystem during the growing season (from May to October) was continuously measured using a 7layer profile system in Anji, Zhejiang Province in 2011. The synchronized CO₂ flux and meteorological data were applied to explore the temporal and spatial variations in the CO₂ concentration and CO₂ storage flux. The results showed that the CO₂ concentration of P. edulis forest during the growing season exhibited obvious diurnal and seasonal variations, as well as vertical variations. In a single day, the CO₂ concentration reached the maximum value at  the daybreak, and decreased to the minimum value in the afternoon after a rapid emission process. In the entire growing season, the minimum CO₂ concentration of the forest appeared in July (368.1 μmol·mol^-1), and the maximum one emerged in October (402.6 μmol·mol^-1). What’s more, the CO₂ vertical gradients above the canopy were lower than those in and below the canopy. The vertical gradients in and above the canopy showed a consistent variation trend: positive in the daytime (carbon sink) and negative at night (carbon source). However, the CO₂ vertical gradients below the canopy were negative throughout the day. We found the proportion of the CO₂ storage flux obtained from the profile system to net-ecosystem CO₂ exchange (NEE) was 25.5% and 8.9% at a halfhour and daily scale, respectively, but was only 0.22% at a monthly scale. The results suggested that CO₂ storage flux could not be neglected when NEE was estimated at a halfhour or daily scale, but could be ignored at a monthly or longer time scale.

Key words: clone library, airborne bacteria, airborne fungi, community structure, microbial diversity.