摘要
Methane (CH4) and carbon dioxide (CO2) emission was measured from mires in the Sanjiang Plain, Northeast China, by using a static chamber technique during free snow-covered periods. The seasonal mean emission of CH4 was 12.4mg/(m2·h) and the emission range of CO2 was 8.7-16.6g/(m2·d) (gross CO2 flux) during plant growth period. CO2 emission rate in the day was stronger than that at night, and the daily peak appears at 19:00. The mire plants in the Sanjiang Plain begin to sprout at the end of April. The aboveground biomass of the mire plants increased from zero to the peak from July to September and showed single peak form. The aboveground biomass of Carex lasiocarpa (464.8g/m2) was lower than that of Deyeuxia platyphylla (530.8g/m2), but the underground biomass was higher than that of Deyeuxia platyphylla. Gross CO2 flux showed the significance positive correlation relationship with plant biomass. Gross CO2 flux and CH4 emission were also correlated with soil temperature (0-5cm) and water temperature. However, the highest CH4 emission rate lagged behind the highest soil temperature in the root area during plant growth period. The data also indicated that wet and warm conditions during the early spring led to greater value of CH4 emission flux. Inundation is the necessary condition for the existence of methane bacteria, but there is no significant positive correlation between the inundation depth and CH4 emission rate in this region. Within the same growing season and under the same inundation condition, the variations of CH4 emission rate could be markedly different.
Methane (CH_4) and carbon dioxide (CO_2) emission was measured from mires inthe Sanjiang Plain, Northeast China, by using a static chamber technique during free snow-coveredperiods. The seasonal mean emission of CH_4 was 12.4mg/(m^2·h) and the emission range of CO_2 was8.7-16.6g/(m^2·d) (gross CO^2 flux) during plant growth period. CO_2 emission rate in the day wasstronger than that at night, and the daily peak appears at 19:00. The mire plants in the SanjiangPlain begin to sprout at the end of April. The aboveground biomass of the mire plants increased fromzero to the peak from July to September and showed single peak form. The aboveground biomass ofCarex lasiocarpa (464.8g/m^2) was lower than that of Deyeuxia platyphylla (530.8g/m^2), but theunderground biomass was higher than that of Deyeuxia platyphylla. Gross CO_2 flux showed thesignificance positive correlation relationship with plant biomass. Gross CO_2 flux and CH_4 emissionwere also correlated with soil temperature (0-5cm) and water temperature. However, the highest CH_4emission rate lagged behind the highest soil temperature in the root area during plant growthperiod. The data also indicated that wet and warm conditions during the early spring led to greatervalue of CH_4 emission flux. Inundation is the necessary condition for the existence of methanebacteria, but there is no significant positive correlation between the inundation depth and CH_4emission rate in this region. Within the same growing season and under the same inundationcondition, the variations of CH_4 emission rate could be markedly different.
基金
Foundationitem:UndertheauspicesoftheKnowledgeInnovationProjectofChineseAcademyofSciences(No.KZCX1-SW-01
KZCX13-SW-262)
