Hu Yi-Gang, Feng Yu-Lan, Zhang Zhi-Shan, Huang Lei, Zhang Peng, Xu Bing-Xin
Ying Yong Sheng Tai Xue Bao. 2014 Jan;25(1):61-8.
Uncertainties still existed for evaluating greenhouse gases fluxes (GHGs), including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) at the regional scale for desert ecosystem because available GHGs data about biological soil crusts (BSCs) was very scarce. In 2011 and 2012, soil ecosystem covered by various types of BSCs and BSCs at different succession stages in an artificial sand-fixing vegetation region established in various periods at southeast of the Shapotou area in Tengger Desert was selected to measure fluxes of CO2, CH4 and N2O using static chamber and gas chromatography. The results showed that curst type, recovery time and their interactions with sampling date significantly affected CO2 flux. Recovery time and interaction of crust type and sampling date significantly affected CH4 flux. Sampling date significantly affected the fluxes of CO2, CH4 and N2O. The mean annual flux of CO2 for moss crust (105.1 mg x m(-2) x h(-1)) was significantly higher than that of algae crust (37.7 mg x m(-2) x h(-1)) at the same succession stage. Annual mean CH4 and N2O consumption was 19.9 and 3.4 microg x m(-2) x h(-1), respectively. Mean annual consumption of CH4 and N2O for algae crust was slightly higher than that of moss crust, however, significant difference was not found. Ecosystem respiration (Re) of desert soil covered by BSCs increased with the recovery process of desert ecosystem, in contrast, consumption of CH4 and N2O decreased. Re of moss crust was more sensitive to temperature and moisture variation than algae crust and Re sensitivity of temperature and moisture gradually increased with the development and succession of BSCs. Both soil temperature and moisture were not the main factor to determine CH4 and N2O fluxes of BSCs-soil in desert ecosystem.
在区域尺度上评估沙漠生态系统中包括二氧化碳（CO₂）、甲烷（CH₄）和一氧化二氮（N₂O）在内的温室气体通量仍存在不确定性，因为有关生物土壤结皮（BSCs）的可用温室气体数据非常稀缺。2011年和2012年，在腾格里沙漠沙坡头地区东南部不同时期建立的人工固沙植被区，选择了覆盖各种类型生物土壤结皮以及处于不同演替阶段的生物土壤结皮的土壤生态系统，使用静态箱和气相色谱法测量CO₂、CH₄和N₂O的通量。结果表明，结皮类型、恢复时间及其与采样日期的相互作用显著影响CO₂通量。恢复时间以及结皮类型与采样日期的相互作用显著影响CH₄通量。采样日期显著影响CO₂、CH₄和N₂O的通量。在相同演替阶段，苔藓结皮的年平均CO₂通量（105.1 mg·m⁻²·h⁻¹）显著高于藻类结皮（37.7 mg·m⁻²·h⁻¹）。CH₄和N₂O的年平均消耗量分别为19.9和3.4 μg·m⁻²·h⁻¹。藻类结皮的CH₄和N₂O年平均消耗量略高于苔藓结皮，但未发现显著差异。生物土壤结皮覆盖的沙漠土壤的生态系统呼吸（Re）随着沙漠生态系统的恢复过程而增加，相反，CH₄和N₂O的消耗量减少。苔藓结皮的Re对温度和水分变化比藻类结皮更敏感，并且随着生物土壤结皮的发育和演替，温度和水分的Re敏感性逐渐增加。土壤温度和水分都不是决定沙漠生态系统中生物土壤结皮-土壤CH₄和N₂O通量的主要因素。
