Simulated rain addition modifies diurnal patterns and temperature sensitivities of autotrophic and heterotrophic soil respiration in an arid desert ecosystem |
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| Institution: | 1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;2. Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China;3. Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China;4. Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084, China;1. School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China;2. School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China;1. Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan;2. Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto 612-0855, Japan;3. Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan;1. College of Environmental Science and Engineering, Taiyuan University of Technology, 79 Yingzexi Street, Taiyuan 030024, China;2. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun Xiangshan, Haidian District, Beijing 100093, China;1. College of Resources and Environmental Science, East China Normal University, Shanghai 200241, China;2. Tiantong National Station of Forest Ecosystem, Chinese National Ecosystem Observation and Research Network, Ningbo 315114, Zhejiang Province, China;3. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden;4. Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708, USA;1. State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, Henan, 475004, China;2. Key Laboratory of Forest Ecology and Environment, China’s State Forestry Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, 100091, China |
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| Abstract: | The timing and magnitude of rainfall events in arid and semiarid regions are expected to change dramatically in future decades, which will likely greatly affect regional carbon cycles. To understand how increases in rainfall affect the diurnal patterns and temperature sensitivities (Q10) of soil respiration (RS) and its key components (i.e. heterotrophic respiration (RH) and autotrophic respiration (RA)), we conducted a manipulative field experiment in a desert ecosystem of Northwest China. We simulated five different scenarios of future rain regimes (0%, 25%, 50%, 75% and 100% increase over local annual mean precipitation) each month from May to September in 2009. We measured RS and RH every three hours on 6 and 16 days after the rain addition, and estimated RA by calculating the difference between RS and RH. We found that rain addition significantly increased the daily mean RS and its components on the two measurement days during the growing season. However, the diurnal pattern was different between the two respiration components. Rain addition significantly increased the daily Q10 value of RH but suppressed that of RA on Day 6. Rain addition had no influence on daily Q10 value of both respiration components on Day 16 when soil moisture was lower. In addition, we observed significantly higher daily Q10 of RH than RA under all five rain addition treatments, indicating that microbial respiration is more temperature sensitive than root respiration in a short-time scale in this desert ecosystem. Thus, partitioning soil respiration into its two components, and analyzing the differential responses of RH and RA to future climate changes should be considered for more accurate predictions of soil respiration and regional carbon cycle in these arid and semiarid regions. |
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| Keywords: | Precipitation change Soil moisture Heterotrophic respiration Autotrophic respiration |
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