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In order to determine the potential of α‐cellulose δ18O (δ18Ocell) data from multiple terrestrial plant species on an ecosystem level to record the δ18O data of precipitation (δ18Op), 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°N in latitude, ~81 to 124°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 δ18Ocell data show a similar spatial pattern to that of δ18Op. The results demonstrate that the measured values of δ18Ocell data have the potential to record variations in δ18Op. Further analysis indicated that the δ18Ocell data from the Tibetan Plateau were primarily controlled by the moisture sources. Interestingly, there are significant negative correlations between δ18Ocell/δ18Op and altitude on the Tibetan Plateau, implying the potential of δ18Ocell for paleoaltimetry in this region. The δ18Ocell 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 δ18Ocell studies aimed to improve our understanding of environmental, hydrological, and climatic changes in inland China and elsewhere. Key Points: The δ18Ocell of plant residues in surface soils from a vast spatial domain can track δ18Op variationsThe δ18Ocell shows an latitude effect in the northern region of China, but an inverse latitudinal pattern on the Tibetan PlateauTemperature/moisture source is the major control factor of δ18Ocell in the northern region of China/on the Tibetan Plateau, respectively [ABSTRACT FROM AUTHOR]

The aeolian loess blanketing the Chinese Loess Plateau (CLP) is sensitive to climate change in monsoonal East Asia. Here, we present a multi-proxy climatic record from a Pleistocene loess-paleosol sequence from the Lantian Basin on the southern margin of the CLP. The measurements include magnetic susceptibility and related magnetic properties, bulk median grain-size, color reflectance, and the color-inferred hematite versus goethite ratio (Hm/Gt). A long-term aridification and cooling trend during the interval from ca 2.22–0.43 Ma is indicated by two magnetic grain-size proxies, corresponding to the global climatic cooling of the late Cenozoic. In addition, at least four intervals of climatic extremes are evident in the record of Hm/Gt ratio: at 1.71–1.65 Ma, 1.26–1.24 Ma, 0.94–0.86 Ma, and 0.62–0.48 Ma. These intervals are characterized by distinct regional climates, which contrast with the global climatic conditions represented in marine sediments. For example, a relatively arid climate is documented from 1.71 to 1.65 Ma, which was rapidly succeeded by a relatively humid climate which is associated with the earliest hominin (with an age of ca 1.63 Ma) in the Lantian Basin. [ABSTRACT FROM AUTHOR]

• Continuous monitoring of water stable isotope in precipitation, soil, and plant. • There is a pronounced seasonal variation of the stable isotopes in twig xylem water. • A higher slope of the soil water line than LMWL is explained. The hydrogen and oxygen stable isotopic (2H and 18O) tracer method has become an important means of studying water transfer between the atmosphere, rivers and lakes, soils, plants, and aquifers. We conducted a study on the variations of the stable isotopes of water, and the seasonal variations in water use of Cinnamomum camphora , in the soil-plant-atmosphere continuum in a C. camphora woodland in Changsha, central-southern China, which lies within the monsoon region of East Asia. Stable isotopes were monitored in precipitation, soil water (0–130-cm depth), groundwater, twig xylem water of C. camphora , and at the same time relevant environmental variables (soil water content, and meteorological variables) were measured, from March 2017 to August 2019. The monitoring data were collated and analyzed to determine the variations of stable isotopes in different water pools and mutual exchanges. The results indicate that daily precipitation (P) greater than 3.7 mm (regarded as effective precipitation) contributed to soil water replenishment. Isotopic composition of soil water and twig xylem water fell below the LMWL P>3.7 (the local meteoric water line eliminated rainfall events with P ≤ 3.7 mm). Isotopic composition of shallow soil water (0–60 cm) and twig xylem water was positively correlated with that of cumulative antecedent precipitation within two months. These patterns of precipitation isotopic signal propagation delineate a clear pathway of water transfer in this soil and plant continuum. The slope of the soil water line in the study area was higher than that of the LMWL P>3.7 because of the situation that precipitation in warm season with a larger evaporative demand is more depleted with heavy isotopes (i.e., more negative delta values) than that in cold season when the evaporative demand is low. Therefore, it was not feasible to determine the strength of isotopic fractionation based on the isotopic water line method. According to the MixSIR model, C. camphora water uptake mainly sourced from shallow soil water during the observation period. However, in July-September when soil was dry, deep soil water (60–130 cm) contributed to C. camphora water uptake for ~50%. These findings improve our understanding of the water cycle of the soil-plant-atmosphere continuum in the East Asian monsoon region. [ABSTRACT FROM AUTHOR]