Global climate change has accelerated the reduction of permafrost regions across different altitude gradients, shortening the duration of the freezing period to varying extents. However, the response of the soil microorganisms of frozen soils along altitude gradients remains unclear. In this study, we employed 16S rRNA sequencing and LC-MS metabolomics to investigate the response of soil microbial communities and soil metabolites to vertical stratification in the permafrost soils of the Qinghai Lake region. The results indicated that Proteobacteria, Firmicutes, and Actinobacteria were key soil bacterial phyla in the permafrost soils of Qinghai Lake during the freezing period, with Proteobacteria and Firmicutes showing significant sensitivity to vertical stratification (p < 0.05). The majority of the physicochemical factors exhibited a trend of initially increasing and then decreasing with increasing altitude, whereas pH showed the opposite trend. pH and moisture content were identified as the most important environmental factors influencing soil bacterial community structure. Deterministic processes dominated the assembly of bacterial communities of frozen soils in the Qinghai Lake basin. Co-occurrence network analysis showed that increasing altitude gradients led to a higher average degree of the bacterial network, while reducing network complexity and inter-species connectivity. Soil metabolomics analysis revealed that vertical stratification altered the metabolic profiles of 27 metabolites, with the significantly changed metabolites primarily associated with carbohydrate and amino acid metabolism. In conclusion, the characteristics of the Qinghai Lake permafrost were regulated by regional vertical stratification, which further influenced microbial community structure and soil metabolic characteristics, thereby altering carbon and nitrogen stocks. Specifically, higher altitudes were more favorable for the retention of the carbon and nitrogen stocks of frozen soils in the Qinghai Lake basin.

Medicago sativa is an important forage crop; its value is mainly concentrated in its economic aspects. The growth cycle and growth rate of M. sativa have an important influence on its economic benefits. Alternaria alstroemeriae has often been used as a pathogenic bacterium in previous studies, and studies on the growth-promoting effects of A. alstroemeriae are rare. This study aimed to assess the effects of A. alstroemeriae on the growth parameters of M. sativae and to investigate the molecular and metabolic mechanisms of M. sativa. M. sativa showed significant improvement in plant height, root length, fresh weight, and dry weight compared to uninoculated control plants. By integrating the results of transcriptome and metabolome analysis, A. alstroemeriae may promote plant growth by regulating genes associated with the biosynthetic pathways of flavonoids, anthocyanins, and proanthocyanidins in plants. These research findings provide a theoretical basis for future verification of the molecular response mechanisms and metabolic regulation of A. alstroemeriae-promoted plant growth. This study also provides a theoretical basis for sustainable agricultural development.

As a globally critical carbon reservoir, the response mechanism of wetland ecosystems to climate change on the Qinghai–Tibet Plateau (QTP) has attracted significant scientific scrutiny. This study investigated the temperature sensitivity of cbbL-harboring carbon-sequestering microbial communities and their coupling with carbon–nitrogen cycle dynamics through a simulated field warming experiment conducted in the Wayan Mountains’ river source wetland in the northeastern QTP. Key findings revealed that warming markedly elevated Alpha diversity (ACE and Chao1 indices), whereas Shannon and Simpson indices remained stable, indicating that temperature increases primarily altered community composition by enhancing species richness rather than evenness. Taxonomic analysis demonstrated significant increases in the relative abundances of Cyanobacteria and Actinobacteria, while Proteobacteria retained dominance but exhibited reduced relative abundance. At the genus level, Thioflexothrix, Ferrithrix, and Rhodospirillum dominated the community, with Thioflexothrix and Ferrithrix showing warming-induced abundance increments. Functional predictions indicated that warming preferentially stimulated heterotrophic and photoheterotrophic functional guilds. Soil physicochemical analyses further revealed warming-driven increases in nitrate nitrogen (NN), total carbon (TC), and total nitrogen (TN), concurrent with decreased soil moisture. Redundancy analysis identified TC as the predominant determinant of microbial community structure (followed by TN > NN), while pH and ammonium nitrogen (AN) exerted comparatively limited influence. Strong positive correlations between microbial communities and carbon/nitrogen indicators suggested that enhanced carbon–nitrogen resource availability served as the central driver of community succession. These findings elucidate the temperature-responsive mechanisms of cbbL-type carbon-sequestering microorganisms in alpine wetlands, offering critical insights for the adaptive management of carbon cycling in high-altitude ecosystems and advancing strategies toward achieving carbon neutrality goals.

Denitrification in alpine wetlands critically regulates regional nitrogen budgets and N ₂ O emissions, and nirK -harboring denitrifiers represent an important functional group involved in nitrite reduction during denitrification. Spatial heterogeneity across distinct plant communities can modulate soil microenvironments, thereby shaping N ₂ O production, consumption, and emission dynamics. Here, using a space-for-time substitution approach, we investigated four successional stages—early (BS), transitional (CR), middle (EN), and mature (LS)—in the alpine wetlands of Qinghai Lake. High-throughput sequencing combined with a null model framework was applied to characterize the coupling between microbial community patterns and their functional potential. Vegetation succession stimulated microhabitat divergence characterized by shifts in total nitrogen (TN), total carbon (TC), and the carbon-to-nitrogen ratio (CNR). This environmental filtering induced a directional microbial succession, culminating in the highest diversity at the LS stage. The CNR emerged as the primary driver accounting for community variance, mediating a microhabitat niche separation that selectively enriched key heterotrophic denitrifiers (such as Sinorhizobium and Paracoccus ). The βNTI null model revealed that deterministic processes governed community assembly; notably, the underlying assembly rules underwent a fundamental shift as succession advanced, becoming dominated by heterogeneous selection at the LS stage. Co-occurrence networks peaked in complexity at the EN stage but reorganized into a more consolidated, modular, and highly competitive topology at the LS stage. Furthermore, functional profiling indicated that while the BS stage was functionally oriented toward nitrate respiration and nitrogen fixation, the LS stage exhibited a distinct advantage in possessing predicted denitrification-related functional profiles. In summary, vegetation succession reshaped nirK -type denitrifier communities via environmental filtering, steering the assembly mechanisms from stochasticity toward determinism; meanwhile, the “insurance effect” of the diverse community structure sustained stable functional output amid nutrient fluctuations. This study clarifies that vegetation succession is a core driving force of the nitrite-reducing potential of nirK -type denitrifiers, providing micro-scale mechanistic insights for the restoration of degraded alpine wetlands, vegetation reconstruction, and the maintenance of regional nitrogen homeostasis under changing climates.

As a vital ecological security barrier and climate regulator in northwestern China, the spatial patterns and evolving formation mechanisms of ecosystem services within the Qinghai Lake basin hold significant strategic value for ecological conservation and national park development in the region. This study selected land use data during 2000–2020, integrating the equivalent factor method, spatial correlation analysis, and the geodetector approach to systematically investigate the spatial heterogeneity characteristics of ESV in the Qinghai Lake basin and its corresponding driving mechanisms. The results indicate the following: (1) During the period 2000–2020, grassland consistently constituted the primary land cover category within the Qinghai Lake Basin, accounting for over 60% of the total area; water bodies (16.67%) and unused land (16.56%) represented the secondary land use categories. Over this twenty-year period, the total ESV exhibited a slight increasing trend, rising from USD 30.30 × 10⁸ to USD 30.75 × 10⁸, representing a growth of 0.31%. Regulating services constituted the primary component of ESV. The highest contribution to ESV originated from water bodies, with grassland ranking second. (2) ESV displayed a spatial arrangement marked by “high values in the lake center and low values in the surrounding areas” and “higher values in the southeast and lower values in the northwest.” Its spatial correlation exhibits a pronounced positive relationship. The number of units classified as high-high clusters (primarily water bodies at low elevations) and low-low clusters (mainly grasslands and unused land at high elevations) both increased over the study period, indicating a continuous intensification of ESV spatial agglomeration. (3) Results from the geographical detector reveal that both natural and anthropogenic factors collectively drive the spatial variation in ESV, with natural factors exhibiting stronger explanatory capacity. Among these, elevation and temperature are identified as the dominant drivers of ESV spatiotemporal differentiation. The combined effect of two interacting factors surpasses the influence exerted by any single factor in isolation. This research clarifies that the spatial distribution of ESV in the Qinghai Lake Basin, which features “high values in the lake center and low values in the surrounding areas” as well as “higher values in the southeast and lower values in the northwest,” is jointly shaped by the combined control of vertical zonality governed by topographic and climatic factors and the spatial differentiation of human activities. In low-altitude lakeshore zones, ESV rose as a consequence of water body expansion and the enforcement of ecological conservation measures, leading to the emergence of high-value clusters. In contrast, ESV improvement in high-elevation regions remained limited, constrained by fragile natural conditions and minimal human intervention. The insights derived from this research offer a scientific foundation for refining the “one core, four zones, one ring, multiple points” functional zoning framework of the Qinghai Lake National Park, as well as for developing tailored management approaches suited to distinct elevation-based regions.

Precipitation change strongly influences soil microbial communities, and precipitation patterns have become a key factor affecting carbon and nitrogen cycling processes in wetland ecosystems. The cbbL gene is a key gene in the fixation of carbon dioxide during the Calvin cycle. However, the response of cbbL-carrier carbon-fixing microorganisms in the lakeshore wetland to precipitation change remains unclear. To this end, we established 25% and 50% increased and decreased precipitation treatments, along with a natural control, and used high-throughput sequencing to investigate the response of the cbbL-carrier carbon-fixing microbial community in a lakeshore wetland of Qinghai Lake in response to precipitation change. The results showed that a 25% reduced precipitation treatment significantly increased the relative abundance of Chlorophyta and Bradyrhizobium. pH was found to be the most important factor influencing the carbon-fixing microbial community, with a significant positive correlation with Ferrithrix. A 25% increased precipitation treatment significantly increased the relative abundance of aerobic chemoheterotrophy and chemoheterotrophy, while a 25% reduced precipitation treatment significantly increased the relative abundance of nitrogen fixation. The increased precipitation and 50% reduced precipitation treatments shift the community assembly process of cbbL-carrier carbon-fixing microorganisms from randomness to determinism. Co-occurrence network analysis showed that the network complexity and connectivity between species of cbbL-carrier carbon-fixing microorganisms initially decreased and then increased with increasing precipitation. In summary, precipitation change tended to reduce the carbon sequestration potential of the lakeshore wetland, while a 25% reduced precipitation treatment favored the nitrogen fixation process in these wetlands.