title: Abiotic carbonate dissolution traps carbon in a semiarid desert.
abstract: It is generally considered that desert ecosystems release CO2 to the atmosphere, but recent studies in drylands have shown that the soil can absorb CO2 abiotically. However, the mechanisms and exact location of abiotic carbon absorption remain unclear. Here, we used soil sterilization, (13)CO2 addition, and detection methods to trace (13)C in the soil of the Mu Us Desert, northern China. After (13)CO2 addition, a large amount of (13)CO2 was absorbed by the sterilised soil, and (13)C was found enriched both in the soil gaseous phase and dissolved inorganic carbon (DIC). Further analysis indicated that about 79.45% of the total (13)C absorbed by the soil was trapped in DIC, while the amount of (13)C in the soil gaseous phase accounted for only 0.22% of the total absorbed (13)C. However, about 20.33% of the total absorbed (13)C remained undetected. Our results suggest that carbonate dissolution might occur predominately, and the soil liquid phase might trap the majority of abiotically absorbed carbon. It is possible that the trapped carbon in the soil liquid phase leaches into the groundwater; however, further studies are required to support this hypothesis.
authors.affiliation: Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P. R. China.
authors.forename: Keyu
authors.initials: K
authors.lastname: Fa
authors.affiliation: Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P. R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P. R. China.|Key Laboratory of Soil and Water Conservation and Desertification Combating of the Ministry of Education, Beijing Forestry University, Beijing 100083, P. R. China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P. R. China.|Key Laboratory of Soil and Water Conservation and Desertification Combating of the Ministry of Education, Beijing Forestry University, Beijing 100083, P. R. China.
authors.forename: Shugao
authors.initials: S
authors.lastname: Qin
authors.affiliation: Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, P. R. China.|Key Laboratory of Soil and Water Conservation and Desertification Combating of the Ministry of Education, Beijing Forestry University, Beijing 100083, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.affiliation: College of Natural Resources and Environment, Northwest A &F University, Yangling 712100, Shaanxi, P. R. China.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Liu