小兴安岭沼泽甲烷通量日变化分析

Diurnal Variation in Methane Fluxes from Wetlands in Xiaoxing'an Mountains,Northeast China

利用静态暗箱—气相色谱法,研究了小兴安岭7种沼泽类型生长季初期、中期、末期甲烷(CH4)通量的日变化规律,结果表明:小兴安岭沼泽甲烷通量无统一的日变化规律,且与温度和水位两个环境因子的相关性较弱。7个沼泽类型中,仅毛赤杨(Alnus sibirica)沼泽和白桦(Betula platyphylla)沼泽甲烷通量峰值在生长季初期、中期、末期出现的时间大致相同,且都为单峰曲线;苔草(Carex schmidtii)沼泽、灌丛沼泽和落叶松(Larix gmelinii)—泥炭藓(Sphagnumspp.)沼泽甲烷通量的峰值在不同时期出现的时间不同,多数为单峰曲线;落叶松—苔草沼泽和落叶松—藓类沼泽甲烷通量速率较小,多数时间吸收甲烷,没有明显的日变化规律。不同类型沼泽和生长期之间甲烷通量没有统一的日变化规律,说明在进行区域甲烷排放总量的估测时,增加每天的观测频率,或者长期、大量的观测数据可能会对提高估测精度有很大帮助。

An experiment was conducted to observe the diurnal methane fluxes from seven types of wetlands in Xiaoxing＇ an Mountains using the static opaque chamber and gas chromatography techniques. Results showed that no common diurnal variations were found in all the wetlands, and the diurnal patterns were weakly correlated to temperature and water table. The same pattern of diurnal fluxes with unique peak for Alnus sibirica swamp and Betula platyphylla swamp was found, and the peak occurred at the same time of day in different seasons. Marsh, thicket swamp and Larix gmelinii-Sphagnum spp. swamp mosdy displayed a pattern of diurnal fluxes with unique peak, and the peak occurred at different time of day in different seasons. No apparent diurnal variations were observed in Larix gmelinii-Carex schmidtii swamp and Larix gmeliniimoss swamp because of the low flux rates. No common diurnal variations in different seasons for all the wetlands indicated that more measurement frequency or long term and larger observational data should be helpful to the estimation of regional methane fluxes.