title: Contrasting diel hysteresis between soil autotrophic and heterotrophic respiration in a desert ecosystem under different rainfall scenarios.
abstract: Diel hysteresis occurs often between soil CO2 efflux (R(S)) and temperature, yet, little is known if diel hysteresis occurs in the two components of R(S), i.e., autotrophic respiration (R(A)) and heterotrophic respiration (R(H)), and how diel hysteresis will respond to future rainfall change. We conducted a field experiment in a desert ecosystem in northern China simulating five different scenarios of future rain regimes. Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season. We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A). Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower. These findings underline the different roles of biological (i.e. plant and microbial activities) and physical-chemical (e.g. heat transport and inorganic CO2 exchange) processes in regulating the diel hysteresis of R(A) and R(H), which should be considered when estimating soil CO2 efflux in desert regions under future rainfall regime.
authors.affiliation: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084, China.|State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Song
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Shiping
authors.initials: S
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Yadan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084, China.
authors.forename: Guanghui
authors.initials: G
authors.lastname: Lin
mesh_terms: D052818:Autotrophic Processes; D002245:Carbon Dioxide; D002681:China; D003889:Desert Climate; D017753:Ecosystem; D052836:Heterotrophic Processes; D011891:Rain; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D012987:Soil; D002245:Carbon Dioxide