摘要
目前,有关增温条件下荒漠生物土壤结皮(BSCs)-土壤系统与大气之间主要温室气体(CO2、CH4和N2O)通量变化的研究十分匮乏,以致很难准确地评估荒漠生态系统温室气体通量对气候变暖的响应与反馈的方向和程度。该文选择腾格里沙漠东南缘天然植被区由藻类、藓类以及二者混生的3种类型的BSCs覆盖土壤为研究对象,以开顶式生长室(OTC)为增温方式模拟全球变暖,采用静态箱-气相色谱法探究了2012年7月至2013年6月增温和不增温处理下CO2、CH4和N2O通量的变化特征。结果表明:增温和结皮类型对CO2、CH4和N2O通量没有显著影响。采样日期、结皮类型与采样日期,以及增温与结皮类型和采样日期的互作显著影响CO2和CH4通量,增温和采样日期互作显著影响CH4通量。BSCs-土壤系统的CO2、CH4和N2O年通量及其增温潜能在增温和不增温处理下的差异均不显著。CO2通量与5 cm深度的土壤温度呈显著的指数正相关关系,与10 cm深度的土壤湿度呈线性正相关关系;藓类、混生结皮的CH4通量与5 cm深度的土壤温度和10 cm深度的土壤湿度均呈显著的线性负相关关系;3种结皮类型的N2O通量与5 cm深度的土壤温度均无相关关系,藓类结皮的N2O通量与10 cm深度的土壤湿度呈显著的线性负相关关系。藓类结皮的CO2和CH4在增温和不增温两种处理下的通量差异与5 cm深度的土壤温度差异呈显著的负线性相关,藻类结皮N2O的通量差异与温度差异呈近似正相关关系(p=0.051)。以上结果说明:在全球变暖的背景下,荒漠BSCs-土壤系统主要温室气体通量不会有明显的变化,意味着荒漠生态系统温室气体的排放可能对气候变暖没有明显的反馈。
Aims The objectives of this study were to investigate the effects of experimental warming on the fluxes of CO2, CH4 and N2O of biological soil crusts （BSCs） and soil system, and to determine the relationships of the greenhouse gas fluxes with soil temperature and soil moisture.
Methods We used open top chamber to imitate climate warming. Intact soil columns covered with three types of biological soil crusts, including moss, algae and mixed crusts of moss and algae, were collected at the southeast fringe of the Tengger Desert. The fluxes of CO2, CH4 and N2O under warming and non-warming treatments were measured using static chamber and gas chromatography method during the period from July 2012 to June 2013.
Important findings Warming and BSCs types had no significant effects on the fluxes of CO2, CH4 and N2O. The CO2 and CH4 fluxes were significantly affected by sampling date as well as interactions between crust type and sampling date and among warming treatment, crust type and sampling date. An interaction between warming treatment and sampling date also significantly affected the CH4 flux. However, no difference was found in the annual CO2, CH4 and N2O fluxes and global warming potentials （GWP） in the three BSC types between the warming and non-warming treatments. CO2 flux had a significant and positive exponential correlation with soil temperature at 5 cm depth and a significant and negative linear correlation with soil moisture at 10 cm depth. The CH4 fluxes of moss and mixed crusts were significantly and negatively correlated with both soil temperature at 5 cm depth and soil moisture at 10 cm depth. No relationship was found between the N2O flux and soil temperature, while the N2O flux of moss crust was significantly and negatively correlated with soil moisture at 10 cm depth. Differences in CO2 and CH4 fluxes of moss crust between the warming and non-warming treatments were significantly and negatively correlated with the difference of soil temperature at 5 cm depth between the two treatments; whe
出处
《植物生态学报》
CAS
CSCD
北大核心
2014年第8期809-820,共12页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(41101081和31170-385)
中国科学院"西部之光"博士项目
关键词
生物土壤结皮
荒漠
模拟增温
温室气体
biological soil crust, desert, experimental warming, greenhouse gases
