摘要
选取青藏高原东北部疏勒河上游多年冻土区的高寒草甸样地为研究对象,对2011年植物生长季(6—10月)主要温室气体(CO2、CH4CH4和CO2)的排放进行了观测.结果显示:疏勒河上游多年冻土区高寒草甸地表CO2、CH4和N2O排放速率范围分别为7.58～418.60mg.m-2.h-1,-0.20～0.14mg.m-2.h-1和-27.22～39.98μg.m-2.h-1.0～10cm土壤温度、含水量和盐分与CO2和CH4排放速率显著相关,但与N2O排放速率无显著相关.日均排放速率显示,CO2和N2O在整个观测期均表现为排放;CH4在植物返青期和生长旺盛期表现为排放,在枯黄期伴随表层土壤发生日冻融循环时为吸收.从9月30日12:00—10月6日14:40,表层0～10cm土壤经历了3次日冻融循环,CO2和N2O日均排放速率分别由冻融前的60.73mg.m-2.h-1和9.91μg.m-2.h-1提高到122.33mg.m-2.h-1和11.70μg.m-2.h-1.土壤温度、含水量和盐分是影响CO2和CH4排放的重要因子,表层土壤冻融交替作用可提高地表CO2和N2O的排放速率.
Research on emissions of greenhouse gases from permafrost region has been of importance and concerns recently in the study of global climatic and environmental change.Alpine meadow plot of permafrost zone in the upper reaches of Shule River in the northeast margin of Qinghai-Tibetan Plateau was selected as study area,and emissions of CH4,N2O and CO2 were measured using method of static chamber-gas chromatograph techniques during plant growing season（from June to October of 2011）.Combined with environmental factors（included soil temperature,soil moisture,soil salinity,air temperature and relative humidity）,the emission characteristics of three greenhouse gases and their main influence factors were investigated.The results showed that diurnal flux rates ranged from 7.58 to 418.60 mg·m-2·h-1 for CO2,from-0.20 to 0.14 mg·m-2·h-1 for CH4,from-27.22 to 39.98 μg·m-2·h-1 for N2O.Soil temperature,soil moisture and soil salinity was positively correlated with CO2 and CH4 emission rates on a diurnal scale,respectively,whereas there were not significant correlations between these environmental factors and N2O emission rates.Based on mean diurnal flux rates,CO2 and N2O emissions occurred in surface soil during the whole observation periods,whereas CH4 emission in plant returning green stage and vigorously growing stage and absorption in plant scorching stage with diurnal soil freeze-thawing were observed.There were three diurnal freezing-thawing cycles in surface soil（0-10 cm） from 12：00 30th September to 14：40 6th October in 2011.The effect of diurnal freeze-thawing cycle on the CO2 and N2O emissions were obvious,and their emissions rate increased from 60.73 mg·m-2·h-1 and 9.91 μg·m-2·h-1 before freeze-thawing to 122.33 mg·m-2·h-1 and 11.70 μg·m-2·h-1 in the initial stage of freeze-thawing,respectively.Results indicate that with growing seasons,the daily variation patterns of emission/uptake of greenhouse gases differ greatly.Soil temperature,soil moisture,soil salinity are important influence factors for CO2 and CH4 emissions.Freeze-thawing cycle,directly influenced soil moisture and contents of active substances,facilitated emission rates of CO2 and N2O in initial period of diurnal freeze-thawing on October.
出处
《冰川冻土》
CSCD
北大核心
2012年第5期1149-1156,共8页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(41171054
41201061
40901040)
中国科学院寒区旱区环境与工程研究所人才基金项目
冰冻圈科学国家重点实验室自主课题(SKLCS-ZZ-2012-02-02)
冰冻圈科学国家重点实验室开放基金项目(SKLCS10-08)
中国博士后特别资助项目(201104347)资助
关键词
多年冻土
温室气体
土壤
高寒草甸
冻融循环
permafrost
greenhouse gas
soil
alpine meadow
freeze-thawing cycle
