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Aim: Species–area relationships (SAR) are widely utilized for estimating the species richness and its spatial turnover across various scales. Despite the prevalent characterization of SAR using the power law in many microbial community studies, its efficacy remains unvalidated. This study aims to characterize the microbial SAR and its mechanisms in alpine grassland soils on the Qinghai‐Tibet Plateau (QTP). Location: Qinghai‐Tibet Plateau, China. Time Period: August 2014. Major Taxa Studied: Soil bacteria. Methods: Soil samples were collected from five alpine grassland sites on the QTP. Employing a nested sampling strategy at each site, soil samples were collected in plot sizes ranging from 0.5 × 0.5 m2 to 2048 × 2048 m2. Soil bacterial communities were analysed by sequencing 16S ribosomal RNA gene amplicons using an Illumina MiSeq. Results: The bacterial SAR exhibited a logarithmic power law (R2: 0.952–0.999), outperforming the power law (R2: 0.701–0.852). Consequently, the most widely adopted power law led to an overestimation of species richness by up to 15.07% in areas >256 × 256 m2, and the regional maximum theoretical richness based on Chao1 by up to 9.88%. Mechanistically, the passive sampling hypothesis was refuted through the rarefied species richness analysis, and the disproportionate effect hypothesis was rejected based on analyses of the effective numbers of species number conversions for the probability of interspecific encounters (SPIE). Notably, Pearson and multiple linear regression analyses indicated that the spatial turnover of bacterial richness was determined by the environmental heterogeneity (R2: 0.855–0.999), rather or better than environmental variables themselves, supporting the 'environment heterogeneity hypothesis'. Main Conclusions: Soil bacterial SAR in alpine grasslands exhibited a logarithmic power relationship. Spatial turnover was primarily governed by the environmental heterogeneity. In contrast, the traditional power law leads to an overestimation of soil bacterial diversity at the regional scale. [ABSTRACT FROM AUTHOR]

To provide evidence-based medicine references for formulating prevention and control policies in plateau areas, we explore the characteristics of anemia patients in Tibet (the plateau areas of China), especially those located at an altitude above 4500 m. We collected clinical data from 379 Tibetan anemia patients over the age of 18 years. We found those female patients accounted for the majority of Tibetan anemia patients. Almost half of the anemia patients aged from 28 to 47 years. The percentage of severe anemia and extremely severe anemia was 45.4% and 2.4%, respectively. 88.7% of patients are engaged in agriculture and animal husbandry, and 81.5% of patients just graduated from primary school or below. The most common causes of anemia were nutritional anemia, especially iron-deficiency anemia. At high-altitude localities, folic acid-deficiency anemia needs more attention. Overall, this study showed that altitude influences the incidence, severity, and cause of anemia. Peasants and herdsmen, low education levels, young and middle-aged women, and nutrition status should be paid attention to in future anemia control. [ABSTRACT FROM AUTHOR]

Changes in labile carbon (LC) pools and microbial communities are the primary factors controlling soil heterotrophic respiration (Rh) in warming experiments. Warming is expected to initially increase Rh but studies show this increase may not be continuous or sustained. Specifically, LC and soil microbiome have been shown to contribute to the effect of extended warming on Rh. However, their relative contribution is unclear and this gap in knowledge causes considerable uncertainty in the prediction of carbon cycle feedbacks to climate change. In this study, we used a two‐step incubation approach to reveal the relative contribution of LC limitation and soil microbial community responses in attenuating the effect that extended warming has on Rh. Soil samples from three Tibetan ecosystems—an alpine meadow (AM), alpine steppe (AS), and desert steppe (DS)—were exposed to a temperature gradient of 5–25°C. After an initial incubation period, soils were processed in one of two methods: (a) soils were sterilized then inoculated with parent soil microbes to assess the LC limitation effects, while controlling for microbial community responses; or (b) soil microbes from the incubations were used to inoculate sterilized parent soils to assess the microbial community effects, while controlling for LC limitation. We found both LC limitation and microbial community responses led to significant declines in Rh by 37% and 30%, respectively, but their relative contributions were ecosystem specific. LC limitation alone caused a greater Rh decrease for DS soils than AMs or ASs. Our study demonstrates that soil carbon loss due to Rh in Tibetan alpine soils—especially in copiotrophic soils—will be weakened by microbial community responses under short‐term warming. [ABSTRACT FROM AUTHOR]

Linkages between soil potentials and microbial functional genes are central in microbial ecology, though conflicting results have been obtained. Here, we investigated such linkages for log-transformed abundances of nitrogen (N) genes from grassland soils. The soil nitrification potential increased with rising A- amoA abundance only after it reaching 8.49 × e10 copy numbers g−1 soil, while the denitrification potential was positively correlated with narG and nirS after 8.44 × e10 and 8.12 × e10 copy numbers g−1 soil, respectively. Moreover, nitrification potential increased with rising ratio of A- amoA /B- amoA more strongly with a higher R2 after a threshold of 5.94, indicating that A- amoA controlled corresponding potential when it was abundant enough to overwhelm B- amoA. Our evaluation revealed the complexity between specific N genes and soil potentials, which were far from single linear relationships and abundant enough genes are necessary to correlate positively with corresponding functional potentials. • Complexities between specific nitrogen genes and soil potentials, which were far from single linear relationships. • A- amoA was positively correlated with NEA only when it became abundant enough after threshold. • narG and nirS were positively correlated with DEA and DN 2 when they became abundant enough. • A- amoA controlled NEA when it became abundant enough and overwhelmed B- amoA. [ABSTRACT FROM AUTHOR]

The polar regions, comprising the Antarctic, Arctic and Tibetan Plateau, represent the most extreme environments on Earth. Soils across the polar regions harbor diverse microorganisms, which dominate the biogeochemical cycling. However, polar soil microbial diversity is largely underrepresented, and has not been directly compared with the non-polar regions at a global scale, which hinders our understanding of the potential importance of polar microbial diversity. In this study, we investigated the global microbial diversity and taxonomy by comparing 1114 soils, derived from the Antarctic (203), Arctic (432), Tibetan Plateau (104) and non-polar regions (375) across all continents. Soil microbial diversity was found to increase gradually from the Antarctic < Arctic < Tibetan Plateau and < non-polar regions. Soil microbial diversity dominantly corresponded to mean summer temperature in the polar regions and to soil pH in non-polar regions, respectively. Soil microbial community structure significantly differed across the different biogeographical regions, while the Antarctic exhibited the highest habitat-specificity. Over 26,000 phylotypes were observed across global soils, of which 21.8% were unique to the three poles, and 21.2% were apparently ubiquitous globally. Polar soils were dominated by fewer phylotypes, but individual phylotype showed greater dominance than that in non-polar regions. Our study reveals unique patterns of soil microbial diversity and taxonomic compositions in polar regions, and highlights the importance of environmental stresses in controlling soil microbial community. [Display omitted] • Polar soil microbial diversity (SMD) was compared with global non-polar regions. • 21% of the phylotypes were globally ubiquitous, 22% were three-poles specific. • Actinobacteria was the most ubiquitous, Firmicutes was predominately endemic. • SMD corresponded to summer temperature in poles and to soil pH in non-poles. • Polar soils were dominated by fewer microbial phylotypes with greater dominance. [ABSTRACT FROM AUTHOR]

• More susceptible topsoil temperature to warming in alpine steppe than swamp meadow. • Greater thermal changes in alpine steppe than swamp meadow, linked to soil moisture. • Warming postponed frozen onset and reduced frozen days in alpine steppe. • Active layer in alpine steppe distinctly thickened by warming compared to control. Soil thermal regime in permafrost regions is sensitive to climate change and may cause vast ecological consequences under future warming scenarios. However, there still lacks a systematic evaluation on the effect of warming on soil thermodynamics in the different ecosystems of permafrost regions. This study investigated the alterations of soil thermodynamics in alpine swamp meadow and alpine steppe under experimental warming by open-top chambers in permafrost regions of the central Tibetan Plateau. The results showed that air temperature increased significantly with an annual mean increase of 1.4 °C under warming. Compared to alpine swamp meadow, soil thermodynamics represented by soil temperature, soil thermal parameters, soil freeze-thaw process and active layer thickness in alpine steppe was more susceptible to warming. Specifically, soil temperature at 5–40 cm depths increased more in alpine steppe than alpine swamp meadow under warming, especially at topsoil (5–20 cm). Moreover, the increase in soil temperature at topsoil was greater during cold season than warm season. Greater alterations of soil thermal parameters were likely because soil moisture content reduced more in alpine steppe. Regarding soil freeze-thaw process, warming significantly postponed the onset of completely frozen stage and reduced the completely frozen days in alpine steppe. Active layer thickness in alpine steppe distinctly increased by 46 cm on average and showed an increasing trend under warming from 2009 to 2011. Overall, vegetation coverage and soil moisture content were responsible for the different responses of soil thermodynamics to experimental warming. The study has important implications for future scenarios as permafrost and grassland degradation may intensify under climate warming. [ABSTRACT FROM AUTHOR]