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Permafrost ground ice melting could alter hydrological processes in cold regions by releasing water. Currently, there is a lack of gridded data of ground ice from the Qinghai‐Tibet Plateau (QTP). Using 664 borehole sample records, we applied a random forest (RF) method to predict the ground ice content of permafrost between 2 and 10 m depth in three layers (2–3, 3–5, and 5–10 m) at a spatial resolution of 1 km. The RF predictions demonstrated an R2 value exceeding 0.80 for all three layers with a negligible positive overestimation (0.98%–1.85%). The ground ice content of the first layer (2–3 m) can be predicted primarily using climate variables, but the contribution of terrain and soil variables increases as the depth increases. The total water storage of ground ice across the QTP permafrost (2–10 m depth) is approximately 3330.0 km3, with 403.5 km3 in the 2–3 m layer, 857.2 km3 in the 3–5 m layer, and 2069.3 km3 in the 5–10 m layer. This study generated for the first time a gridded dataset of the shallow permafrost ground ice content across the entire QTP which can be used to improve simulations of hydrological processes in the permafrost regions. [ABSTRACT FROM AUTHOR]

Relict permafrost presents an ideal opportunity to understand the impacts of climatic warming on the ground thermal regime since it is characterized by mean annual ground temperature close to 0 °C and relatively thin permafrost. The long-term and continuous observations of permafrost thermal state and climate background are of great importance to reveal the links between the energy balance on hourly to annual timescales, to evaluate the variations of permafrost thermal state over multi-annual periods and to validate the remote sensing dataset. Until now there are few data available in relict permafrost regions although those data are important to understand the impacts of climate changes on permafrost especially in the boundary regions between permafrost and seasonally frozen ground regions. In this study, we present 11 years of meteorological and soil data in a relict permafrost site of the Mahan Mountain on the northeast of the Qinghai-Tibet Plateau. The meteorological data are comprised of air and ground surface temperature, relative humidity, wind speed and direction, shortwave and longwave downward and upward radiation, water vapor pressure, and precipitation on half-an-hour timescale. The active layer data include daily soil temperature and soil moisture at five different depths. The permafrost data consist of ground temperature at twenty different depths up to 28.4 m. The high-quality and long-term datasets are expected to serve as accurate forcing data in land surface models and evaluate remote-sensing products for a broader geoscientific community. The datasets are available from the National Tibetan Plateau/Third Pole Environment Data Center (https://doi.org/10.11888/Cryos.tpdc.271838, Wu and Xie, 2021). [ABSTRACT FROM AUTHOR]

Permafrost has great influences on the climatic, hydrological, and ecological systems on the Qinghai–Tibet Plateau (QTP). The changing permafrost and its impact have been attracting great attention worldwide like never before. More observational and modeling approaches are needed to promote an understanding of permafrost thermal state and climatic conditions on the QTP. However, limited data on the permafrost thermal state and climate background have been sporadically reported in different pieces of literature due to the difficulties of accessing and working in this region where the weather is severe, environmental conditions are harsh, and the topographic and morphological features are complex. From the 1990s, we began to establish a permafrost monitoring network on the QTP. Meteorological variables were measured by automatic meteorological systems. The soil temperature and moisture data were collected from an integrated observation system in the active layer. Deep ground temperature (GT) was observed from boreholes. In this study, a comprehensive dataset consisting of long-term meteorological, GT, soil moisture, and soil temperature data was compiled after quality control from an integrated, distributed, and multiscale observation network in the permafrost regions of QTP. The dataset is helpful for scientists with multiple study fields (i.e., climate, cryospheric, ecology and hydrology, meteorology science), which will significantly promote the verification, development, and improvement of hydrological models, land surface process models, and climate models on the QTP. The datasets are available from the National Tibetan Plateau/Third Pole Environment Data Center (https://data.tpdc.ac.cn/en/disallow/789e838e-16ac-4539-bb7e-906217305a1d/ , last access: 24 August 2021, 10.11888/Geocry.tpdc.271107, Lin et al., 2021). [ABSTRACT FROM AUTHOR]

Permafrost on the Qinghai–Tibet Plateau (QTP) has undergone degradation as a result of recent climate change. This may alter the thermo‐hydrological processes and unlock soil organic carbon, and thereby affect local hydrological, ecological, and climatic systems. The relationships between permafrost and climate change have received extensive attention, and in this paper we review climate change for permafrost regions of the QTP over the past 30 years. We summarize the current state and changes in permafrost distribution and thickness, ground temperature, and ground ice conditions. We focus on changes in permafrost thermal state and in active‐layer thickness (ALT). Possible future changes in ground temperature and ALT are also discussed. Finally, we discuss the changes in hydrological processes and to ecosystems caused by permafrost degradation. Air temperature and ground temperature in the permafrost regions of the QTP have increased from 1980 to 2018, and the active layer has been thickening at a rate of 19.5 cm per decade. The response of permafrost to climate change is not as fast as in some reports, and permafrost degradation is slower than projected by models that do not account for conditions deep in permafrost. [ABSTRACT FROM AUTHOR]

ABSTRACT To determine the relationship between soil organic matter (SOM) decomposition and chemistry in the permafrost region of the Qinghai-Tibet Plateau (QTP), 300-day laboratory incubations at 25°C and chemical fractionation were performed to characterise the mineralisation dynamics of organic carbon from soils under five vegetation conditions. The respiration rates in wet meadows were the highest, followed by the Kobresia pygmaea meadow and K. robusta meadow. After the incubation period, all four fractions of SOM - non-polarity soluble, water soluble, holocellulose and lignin contents - showed some decline, and the SOM decreased by 16-20 per cent in soils of the steppe, meadow and wet meadow. These results suggest that a large proportion of the organic matter in soils of the permafrost region in the QTP is mineralisable. Based on the changes in chemical fractions of organic matter, it could be determined that soils with higher water-soluble fractions had higher rates of carbon mineralisation, while the mechanisms involved in the respiration of different chemical fractions are complicated. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this study, the ground surface temperature (GST) records from 16 meteorological stations, which are located in or adjacent to permafrost regions on the central Qinghai-Tibet Plateau (QTP), are analysed using Mann-Kendal test and Sen's slope estimate methods. We revealed that the GSTs have shown statistically significant warming. On average, mean annual ground surface temperature has increased at a rate of 0.60 °C decade−1 over the period of 1980-2007, which is more pronounced than the increase of mean annual air temperature on the plateau. The winter ground surface warming is especially prominent, which is similar to the seasonal trends in changes of air temperature. As important parameters to assess the changes of ground thermal regime in cold regions, surface freezing and thawing indices were also studied. The nonparametric statistic test and estimate indicate that surface freezing and thawing indices both show significant variations (−111.2 and 125.0 °C d decade−1, respectively) on the central QTP. The intensive ground surface warming is responsible for the concurrent increase in permafrost temperatures at the long-term observation sites on the plateau. The close correlations between ground surface and permafrost temperatures indicate that the dramatic ground surface warming could have significant influence on the change of permafrost thermal regime in the study region. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Kalanchoe pinnata (Lam.) Pers. [syn.: Bryophyllum pinnatum (Lam.) Oken] is an important medicinal agent in southern China. The succulent leaves of this plant are used in the treatment of cholera, bruises, uri-nary diseases and whitlow. In Oct. 2019, leaf spots were detected on K. pinnata plants in Chengmai County, Hainan Province, China. Lesions with brown to black margins were irregularly shaped and associated with leaf margins. Spots coalesced to form larger lesions (Fig. S1-A), with black pycnidia present in more mature lesions. Symptomatic K. pinnata were found with 10-20% incidence during the humid winters of Hainan Province. Leaf tissues of 10 symptomatic plants were collected and surface sterilized in 70% ETOH for 30s, 0.1% HgCl2 for 30 s, rinsed 3x with sterile distilled water for 30s, placed on potato dextrose agar (PDA) amended with 30mg/L of kanamycin sulfate, and incubated at 25°C in the dark for 3-5 days. Four fungal isolates were obtained using a single-spore isolation method. The colonies were floccose, dense, and white with forming on older colonies grown on PDA (Fig. S1-B-1&2). Alpha conidia exuded from ostiole, rostrate, long-beaked pycnidia in creamy-to-yellowish drops. Alpha conidia were hyaline, ellipsoidal, separated and averaged 6.3μm (SD ± 1.13) long × 1.9μm (SD ± 0.33) wide (n=50). Beta conidia were not seen. The morphological characteristics matched the previous description of Diaporthe longicolla (syn. Phomopsis longicolla) (Hobbs et al. 1985). Mycelial genomic DNA of the representative isolate LDSG3-2 was extracted as template. The internal transcribed spacer (ITS) , translation elongation factor 1α gene (TEF) and β-tubulin (TUB2) regions were amplified. These loci were amplified using primer pairs ITS4/ITS5 (White, et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999) and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. A BLAST search of GenBank showed ITS (MN960195), TEF (MN974483) and TUB2 (MN974482) sequences of the isolate were 99%, 100%, and 99% homologous with D. longicolla strains DL11 (MF125048, 557/563 bp), D55 (MN584792, 347/347 bp) and DPC-HOH-32 (MK161506, 502/504 bp). Maximum likelihood trees based on concatenated nucleotide sequences of the three genes were constructed using MEGA 7.0, and bootstrap values indicated the isolate was D. longicolla (Fig. S1-D). Pathogenicity testing was performed using isolate LDSG3-2 by depositing 5µl droplets of a conidial suspension (1 × 106 ml-1) into 5 artificially wounded leaves (using a sterile needle) of 10 healthy 3-month-old K. pinnata plants. An equal number of artificially wounded control leaves were inoculated with sterile water to serve as a negative control. The test was conducted three times. Plants were kept at 25°C in 80% relative humidity and observed for symptoms. Two weeks after inoculation, no symptoms were observed on control plants (Fig. S1-C-1) and all inoculated plants showed symptoms (Fig. S1-C-2) similar to those observed in the field. The fungus was re-isolated from the infected tissues and showed the same cultural and morphological characteristics of the strain inoculated and could not be isolated from the controls fulfilling Koch's postulates. To our knowledge, this is the first report of leaf spot on K. pinnata caused by D. longicolla in China. This disease is of concern since Phomopsis diseases are common in K. pinnata fields and can cause significant reduction in yield. References: White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. DOI: 10.1016/0167-7799(90)90215-J Carbone, I., and Kohn, L. M. 1999. Mycologia. 91:553. DOI: 10.2307/3761358 Glass, N. L., and Donaldson, G. C. 1995. Appl. Environ. Microbiol. 61:1323. DOI: 10.1002/bit.260460112 Hobbs, T. W. et al. 1985. Mycologia. 77: 535. DOI: 10.2307/3793352.