盐生荒漠生态系统二氧化碳通量的年内、年际变异特征

摘要/Abstract

摘要： 采用涡度相关法,并结合小气候观测,对荒漠生态系统净二氧化碳通量进行了连续3个生长季的观测（2004—2006年）,并据此分析了荒漠生态系统净二氧化碳通量及其主要成分GPP和Reco的季节和年际间变化特征。结果表明,在生长季尺度上,各个阶段二氧化碳吸收量的大小分别为:生长旺盛期>生长初期>生长末期,这可能与植物叶面积的大小以及光合有效辐射,大气温度等环境要素有关系。在年际尺度上,3个生长季同阶段的二氧化碳吸收量存在明显差异,生长季初期5月,2004年碳吸收最强,2006年次之,2005年最小。对于生长旺盛期,降水量最大的2004年碳吸收能力最强,正午最大值可以达到-0.12 mg·m-2·s-1,2005年次之,最大值达-0.06 mg·m-2·s-1,仅仅是2004年最大值的1/2,2006年最小,正午吸收的最大值为-0.02 mg·m-2·s-1,生长季末期,3个生长季的月均日变化非常相似,其在正午的最大吸收值也没有显著差异,正午最大吸收量为-0.01 mg·m-2·s-1左右,其他时段均在0值附近。即使在降水量相近的两个年份里（2005—2006年）,其NEE的最大值出现时间也不一致,2005年NEE的最大月累计量出现在8月和9月,而2006年则出现在6月和7月,这可能与年内降水量分布格局有关。3个生长季荒漠生态系统均表现为净二氧化碳吸收,其吸收量分别为:-236.18 g·m-2,-63.07 g·m-2和-91.97 g·m-2。年际差异的形成原因是降水差异造成的一年生草本植物数量变化,不利用降水的建群种应该对此没有贡献。

关键词: 二氧化碳通量, 盐生荒漠生态系统, 涡度相关技术, 生态系统呼吸

Abstract: Using eddy covariance technology, we measured the CO2 flux in a desert ecosystem during growing seasons of 2004—2006. The seasonal and annual variability of the CO2 flux(NEE) and gross primary production (GPP) and ecosystem respiration (Reco) were analyzed based on observation data. NEE, GPP, Reco had a similar seasonal variation trend, and their values follow a sequence of values in growth period>in initial growth period>in terminal growth period. Obvious difference can be seen in annual trends of GPP, NEE, and Reco. The peak NEE value was -4.66 g·m-2·d-1, -1.94 g·m-2·d-1 and -2.02 g·m-2·d-1 in 2004, 2005 and 2006 respectively. Carbon uptake occurred mainly in June, July and August of the growing season. Carbon uptake occurred in the three years, and the value was -236.18 g·m-2, -63.07 g·m-2, and -91.97 g·m-2 in order. The results indicate that, in contrast to previous research, desert ecosystem can be a significant carbon sink and an important component of the global carbon budget.

Key words: CO2 flux, salt desert ecosystem, eddy covariance technology, ecosystem respiration

中图分类号:

Q945.1

刘冉;李彦*;王勤学;许皓;郑新军. 盐生荒漠生态系统二氧化碳通量的年内、年际变异特征[J]. 中国沙漠, 2011, 31(1): 108-114.

LIU Ran;LI Yan;WANG Qin-xue;XU Hao;ZHENG Xin-jun. Seasonal and Annual Variations of Carbon Dioxide Fluxes in Desert Ecosystem[J]. JOURNAL OF DESERT RESEARCH, 2011, 31(1): 108-114.

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