我国亚热带毛竹林CO_2通量的变异特征

Variation characteristics of CO_2 flux in Phyllostachys edulis forest ecosystem in subtropical region of China

2010年12月至2011年11月,利用涡度相关技术研究了我国亚热带(浙江)毛竹林生态系统的CO2通量,分析了毛竹林净生态系统交换量(NEE)、生态系统呼吸量(RE)和生态系统总交换量(GEE)的变化.结果表明:研究期间,毛竹林各月的NEE均为负值,7月最大,为-99.33 g C·m-2,11月最小,仅-23.49 g C·m-2,其变化曲线呈双峰型.各月CO2通量平均日变化差异明显,9月最大,为-0.60 g CO2·m-2·s-1,1月最小,为-0.30 g CO2·m-2·s-1,且在NEE正负转换的时间点上呈明显的季节变化特征;全年RE呈单峰型变化,夏季最高、冬季最低,夜间RE与土壤温度呈极显著正相关.全年NEE、RE和GEE分别为-668.40、932.55和-1600.95 g C·m-2·a-1,NEE占GEE的41.8%.与其他生态系统相比,毛竹林的固碳能力极强.

By using eddy covariance technique, this paper studied the CO2 flux in a Phyllostachys edulis forest ecosystem with high-efficiency management in Zhejiang Province of China from Decem- ber, 2010 to November, 2011, and analyzed the variations of net ecosystem exchange （NEE）, ecosystem respiration （RE） , and gross ecosystem exchange （GEE）. During the study period, the monthly NEE was always negative, with the maximum （ -99.33 g C ~ m-2） in July and the mini- mum （-23.49 g C ~ m-2） in November, and the seasonal change showed a bimodal shape. The average diurnal change of the monthly CO2 flux varied greatly from -0.30 g CO2 ~ m-2 ~ s-~ （Janu- ary） to -0.60 g CO2 ~ m-2 ~ s-1 （September）. The NEE at the time point of positive and negative conversion had obvious seasonal characteristics. The yearly RE changed in unimodal shape, with the maximum in summer and the minimum in winter. The RE at nighttime had significant negative correlation with soil temperature. The yearly NEE, RE, and GEE were -668.40, 932.55, and -1600.95 g C m-2 a-1, respectively, among which, the NEE occupied 41.8% of the GEE. As compared with other ecosystems, P. edulis forest ecosystem had a strong capability in carbon se- questration.