摘要
工业革命以来 ,人类活动所导致的 CO2 等温室气体的浓度在大气中持续上升 ,全球表面温度因此不断升高。在全球温暖化的背景下 ,土壤呼吸与温室效应之间正反馈关系势必影响到未来陆地生态系统功能与全球变化的趋势 ,所以 ,关于土壤呼吸对温度变化响应的研究备受瞩目。土壤呼吸对温度依赖性的研究已经有许多报道 ,其关系可以用简单的指数方程表示。但是 ,土壤水分条件对于土壤呼吸温度敏感性 (用 Q1 0 表示 )的影响却研究得较少。采用碱液吸收法对内蒙古典型温带草原 11个不同水分状况群落的土壤呼吸进行了测定 ,并分析了土壤呼吸的温度敏感性。结果显示土壤呼吸的温度敏感性存在一定程度的空间变异 ,各群落 Q1 0 值平均为 1.6 5 ,变异系数为 6 .94 %。其中 ,春小麦群落的 Q1 0 值最高 (1.84 ) ,其次是湿生杂类草群落 (Q1 0 =1.78) ,而 Q1 0 最低的是冷蒿 (Armesia frigida) -星毛萎陵菜 (Potentilla acaulis)群落 (1.4 7)。用 Spearm an秩相关分析法对表层土壤(0～ 2 0 cm )水分与 Q1 0 值之间的关系进行了分析 ,结果表明各群落 Q1 0 值与生长季土壤平均水分含量呈显著的正相关关系 (R=0 .6 4 5 4 5 ,p=0 .0 32 ) ,说明水分状况对土壤呼吸的温度敏感性有一定程度的影响。由此推断 ,在中国温带草原地区 ,?
Atmospheric concentrations of greenhouse gases have increased dramatically since the beginning of industrial revolution due to human activities such as fossil fuel combustion and land-use change. Because of the increasing atmospheric concentrations of greenhouse gases and their greenhouse effect, a recent IPCC report has predicted that a much warmer climate is coming. Carbon dioxide is one of the most concerned greenhouse gases in the study of global climate change. Because soil respiration is a major process that controls and influences atmospheric CO_2 concentration, response of soil respiration to temperature changes has become a focal point in studies of the global carbon cycle. In addition to temperature soil moisture is another important factor that affects soil respiration. While many studies have shown that temperature exerts a major control on soil respiration, the relationship between temperature sensitivity of soil respiration (often expressed as Q _(10)) and soil moisture conditions is rarely investigated. Using the alkali absorption technique, we measured soil CO_2 efflux in 11 temperate steppe communities in Xilin River basin, Inner Mongolia. We calculated the Q _(10) values of soil respiration in the 11 communities, and then analyzed the sensitivity of Q _(10) to soil moisture content (0~20cm). Among the 11 communities, Q _(10) values varied from 1.47 to 1.84, with a mean value of 1.65 and a coefficient of variation of 6.94%. Using the Spearman's Rank-Order correlation method, we also analyze the relationship between Q _(10) values and soil moisture content, and found that Q _(10) values were positively correlated to average surface soil moisture ( R =0.64545, p =0.032), indicating that soil moisture significantly affected soil respiration. Our results showed that the spring wheat field had the greatest Q _(10) value (1.84), followed by the wet mixed grasses ( Q _(10)=1.78). Whereas, the Artemisia frigida -Potentilla acaulis community, had the lowest Q _(10) value (1.47). In the typical temperate steppe, soil temperature tends to have greater impact on soil respiration in wetter habitats than in drier habitats. This also implies that any significant change in the spatio-temporal pattern of soil moisture can have significant effects on soil respiration in the temperate steppe of China, and, therefore, the effect of soil moisture should be taken into account when soil CO_2 efflux is to be modeled on a larger spatial and temporal scale.
出处
《生态学报》
CAS
CSCD
北大核心
2004年第4期831-836,共6页
Acta Ecologica Sinica
基金
中国科学院知识创新工程重大项目(KZCX1-SW-0 1-0 4
KSCX1-0 8-0 3 )
国家重点基础研究发展规划项目 (G2 0 0 0 0 1860 3
G19990 43 40 7)~~
