Precipitation δ18O Recorded by the α-Cellulose δ18O of Plant Residues in Surface Soils: Evidence From a Broad Environmental Gradient in Inland China

In order to determine the potential of alpha-cellulose delta O-18 (delta O-18(cell)) data from multiple terrestrial plant species on an ecosystem level to record the delta O-18 data of precipitation (delta O-18(p)), especially in relatively cold and arid environments, we collected samples of terrestrial plant residues from 104 surface soils covering a large environmental gradient (29 to 51 degrees N in latitude, 81 to 124 degrees E in longitude, 200 to 5,100 m in elevation) in inland China. Despite the diverse vegetation types, wide range of climatic conditions and potentially complex biogeochemical processes operating within the vast study region, the delta O-18(cell) data show a similar spatial pattern to that of delta O-18(p). The results demonstrate that the measured values of delta O-18(cell) data have the potential to record variations in delta O-18(p). Further analysis indicated that the delta O-18(cell) data from the Tibetan Plateau were primarily controlled by the moisture sources. Interestingly, there are significant negative correlations between delta O-18(cell)/delta O-18(p) and altitude on the Tibetan Plateau, implying the potential of delta O-18(cell) for paleoaltimetry in this region. The delta O-18(cell) data from the northern region of China (including the East Asian monsoon-margin and arid central Asia) were mainly controlled by temperature, although the influence of relative humidity in the region is not negligible. Our results provide a fundamental reference for related delta O-18(cell) studies aimed to improve our understanding of environmental, hydrological, and climatic changes in inland China and elsewhere.