荒漠化极大地影响着包括毛乌素沙地在内的干旱、半干旱区的土壤呼吸及碳固持潜力,因而,可能对区域或全球的碳循环造成一定影响。为揭示土壤呼吸的时间变化及其影响因子,理解荒漠化对毛乌素沙地土壤呼吸及碳固持的影响,根据毛乌素沙地荒...荒漠化极大地影响着包括毛乌素沙地在内的干旱、半干旱区的土壤呼吸及碳固持潜力,因而,可能对区域或全球的碳循环造成一定影响。为揭示土壤呼吸的时间变化及其影响因子,理解荒漠化对毛乌素沙地土壤呼吸及碳固持的影响,根据毛乌素沙地荒漠化类型的研究结果,以毛乌素沙地固定沙地本氏针茅群落(FS)、固定沙地油蒿群落(FA)、半固定沙地油蒿群落(SFA)、流动沙地一年生植物群落(AL)等4个代表毛乌素沙地荒漠化主要阶段的植物群落为研究对象,采用LI-8100土壤碳通量测量系统测定了其土壤呼吸速率的日动态和月动态,结合植物群落生产力的野外调查,分析了荒漠化对土壤呼吸速率及碳固持的影响。结果表明:FA、FS、SFA、AL不同月份之间土壤呼吸速率日动态变化显著,4个群落5月份土壤呼吸最高、最低值分别出现在9:00-10:00和18:00,但6-9月份土壤呼吸最高、最低值却分别出现在12:00以后和7:00。FA、FS、SFA、AL在主要生长季(5-9月)的平均土壤呼吸速率分别为:99.79、88.13、47.95、13.82 mg.m-.2h-1。FS、FA和SFA土壤呼吸速率月变化显著,5月最低,7月最高,AL土壤呼吸速率月变化相对较小。FS、FA和SFA土壤呼吸速率月变化与土壤温度存在显著的指数相关关系,FS、FA、SFA和AL的Q10值依次为5.87、5.05、4.02、0.64。FS和FA的土壤呼吸速率月变化与土壤湿度显著正相关,而SFA和AL的土壤呼吸速率月变化与土壤湿度不存在显著线性关系。土壤呼吸与10 cm深度的土壤温度和湿度回归模型表明土壤温度和湿度可以解释不同群落土壤呼吸月变化的69%-87%。FS、FA、SF和AL的月土壤呼吸速率与根系生物量存在显著线性关系。在主要生长季(5-9月)平均根系呼吸速率和平均土壤微生物呼吸随荒漠化程度的加重而降低。FS、FA、SFA和AL根系呼吸与土壤呼吸的比率分别为51.40%、59.99%、70.85%、45.86%。在主要生长季(5-9月)净生态系统生产力分别为36.16、18.56、-11.29和-22.49 C g/m2。随荒漠化程度的加重,生态系统碳固持能力逐渐降低。因此,采取合理措施使荒漠化土地向以油蒿或本氏针茅为主的固定沙地演替,有助于毛乌素沙地生态系统碳固持能力的提高和植物群落的生长。展开更多
Carbon cycling in terrestrial ecosystems is an important factor that affects the level and accumulation rate of global atmospheric greenhouse gases and determines the stability of the global climate.From 2010 to 2019,...Carbon cycling in terrestrial ecosystems is an important factor that affects the level and accumulation rate of global atmospheric greenhouse gases and determines the stability of the global climate.From 2010 to 2019,31%of CO_(2) emissions caused by human activities were absorbed by vegetation in terrestrial ecosystems and 23%by the ocean,while the remaining 46%accumulated in the atmosphere.However,as the climate continues to warm。展开更多
Soil heterotrophic respiration(Rh)is the flux of CO2 that microbes and soil fauna release to the atmosphere by extracting the energy of organic molecules that they break down[1].Rh closes the terrestrial carbon cycle ...Soil heterotrophic respiration(Rh)is the flux of CO2 that microbes and soil fauna release to the atmosphere by extracting the energy of organic molecules that they break down[1].Rh closes the terrestrial carbon cycle by recycling more than 70%of the annual total fixed carbon to the atmosphere per year so that it can be reused by plants for photosynthesis[2].Rh plays a key role in regulating the changes in atmospheric CO2 concentrations as well as the consequential climate feedbacks[3,4].However,global Rh estimates suffer from large uncertainty.The simulated global Rh value ranges from 30 to 64 Pg C a-1 by MsTMIP models[5],from 47 to 72 Pg C a-1 by Trendy models[6],and from 42 to 73 Pg C a-1 by CMIP5 models[1].High spatial heterogeneity and the close contingency of soil decomposition on environmental changes,such as temperature and soil moisture,may be a response to such great unpredictability[7].Rh is highly transient and variable at diurnal,seasonal and multiyear scales.Short-term observations and limited in situ measurements,as well as low representativeness in many key regions with high soil carbon stocks and difficult accessibilities,such as the northern circumpolar permafrost region and high-altitude Tibetan region,make Rh the most unpredictable process in land-carbon cycle models[8].Accurate estimates of Rh at regional and global scales are thus imperative to quantify the land carbon sink,to evaluate land-carbon cycle models and to define baselines for climate change mitigation efforts.展开更多
文摘荒漠化极大地影响着包括毛乌素沙地在内的干旱、半干旱区的土壤呼吸及碳固持潜力,因而,可能对区域或全球的碳循环造成一定影响。为揭示土壤呼吸的时间变化及其影响因子,理解荒漠化对毛乌素沙地土壤呼吸及碳固持的影响,根据毛乌素沙地荒漠化类型的研究结果,以毛乌素沙地固定沙地本氏针茅群落(FS)、固定沙地油蒿群落(FA)、半固定沙地油蒿群落(SFA)、流动沙地一年生植物群落(AL)等4个代表毛乌素沙地荒漠化主要阶段的植物群落为研究对象,采用LI-8100土壤碳通量测量系统测定了其土壤呼吸速率的日动态和月动态,结合植物群落生产力的野外调查,分析了荒漠化对土壤呼吸速率及碳固持的影响。结果表明:FA、FS、SFA、AL不同月份之间土壤呼吸速率日动态变化显著,4个群落5月份土壤呼吸最高、最低值分别出现在9:00-10:00和18:00,但6-9月份土壤呼吸最高、最低值却分别出现在12:00以后和7:00。FA、FS、SFA、AL在主要生长季(5-9月)的平均土壤呼吸速率分别为:99.79、88.13、47.95、13.82 mg.m-.2h-1。FS、FA和SFA土壤呼吸速率月变化显著,5月最低,7月最高,AL土壤呼吸速率月变化相对较小。FS、FA和SFA土壤呼吸速率月变化与土壤温度存在显著的指数相关关系,FS、FA、SFA和AL的Q10值依次为5.87、5.05、4.02、0.64。FS和FA的土壤呼吸速率月变化与土壤湿度显著正相关,而SFA和AL的土壤呼吸速率月变化与土壤湿度不存在显著线性关系。土壤呼吸与10 cm深度的土壤温度和湿度回归模型表明土壤温度和湿度可以解释不同群落土壤呼吸月变化的69%-87%。FS、FA、SF和AL的月土壤呼吸速率与根系生物量存在显著线性关系。在主要生长季(5-9月)平均根系呼吸速率和平均土壤微生物呼吸随荒漠化程度的加重而降低。FS、FA、SFA和AL根系呼吸与土壤呼吸的比率分别为51.40%、59.99%、70.85%、45.86%。在主要生长季(5-9月)净生态系统生产力分别为36.16、18.56、-11.29和-22.49 C g/m2。随荒漠化程度的加重,生态系统碳固持能力逐渐降低。因此,采取合理措施使荒漠化土地向以油蒿或本氏针茅为主的固定沙地演替,有助于毛乌素沙地生态系统碳固持能力的提高和植物群落的生长。
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2022QZKK0101)the National Natural Science Foundation of China(41988101,42001104,and 41975140)+1 种基金the National Key Scientific and Technological Infrastructure Project“Earth System Science Numerical Simulator Facility”(Earth Lab,201715003471104355)the Innovation Program for Young Scholars of TPESER(TPESER-QNCX2022ZD-01)。
基金supported by the National Natural Science Foundation of China(42022004,41901085,and 41988101)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)。
文摘Carbon cycling in terrestrial ecosystems is an important factor that affects the level and accumulation rate of global atmospheric greenhouse gases and determines the stability of the global climate.From 2010 to 2019,31%of CO_(2) emissions caused by human activities were absorbed by vegetation in terrestrial ecosystems and 23%by the ocean,while the remaining 46%accumulated in the atmosphere.However,as the climate continues to warm。
基金This work was supported by Preliminary Research on Three Poles Environment and Climate Change(2019YFC1509103)the National Natural Science Foundation of China(41861134036 and 41922004)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA19070303 and XDA20050101).
基金the National Natural Science Foun-dation of China(42022004 and 41901085)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0606)。
文摘Soil heterotrophic respiration(Rh)is the flux of CO2 that microbes and soil fauna release to the atmosphere by extracting the energy of organic molecules that they break down[1].Rh closes the terrestrial carbon cycle by recycling more than 70%of the annual total fixed carbon to the atmosphere per year so that it can be reused by plants for photosynthesis[2].Rh plays a key role in regulating the changes in atmospheric CO2 concentrations as well as the consequential climate feedbacks[3,4].However,global Rh estimates suffer from large uncertainty.The simulated global Rh value ranges from 30 to 64 Pg C a-1 by MsTMIP models[5],from 47 to 72 Pg C a-1 by Trendy models[6],and from 42 to 73 Pg C a-1 by CMIP5 models[1].High spatial heterogeneity and the close contingency of soil decomposition on environmental changes,such as temperature and soil moisture,may be a response to such great unpredictability[7].Rh is highly transient and variable at diurnal,seasonal and multiyear scales.Short-term observations and limited in situ measurements,as well as low representativeness in many key regions with high soil carbon stocks and difficult accessibilities,such as the northern circumpolar permafrost region and high-altitude Tibetan region,make Rh the most unpredictable process in land-carbon cycle models[8].Accurate estimates of Rh at regional and global scales are thus imperative to quantify the land carbon sink,to evaluate land-carbon cycle models and to define baselines for climate change mitigation efforts.
