生物土壤结壳(生物结壳)被认为是“沙漠生态系统工程师”,因为它们在沙漠的恢复和稳定维护中起着至关重要的作用,包括高纬度的冷沙地生态系统,尤其是研究不足。微生物参与生物锈病的形成和演替,有助于土壤特性的改善和土壤团聚体的稳定性,从而植被发展。因此,了解微生物的组成和演替特征是分析生物锈病的生态功能和相关应用的前提。这里,选择了中国东北的呼伦贝尔沙地地区,该地区位于该国所有沙地中的最高纬度。通过实地调查和下一代测序(IlluminaMiSeqPE300平台),我们的目标是评估该地区生物锈病演替过程中不同阶段土壤细菌和真菌的多样性和群落组成的变化,并揭示影响其土壤微生物群落形成的主要因素。结果表明,生物锈菌对速效氮的养分富集能力,总氮,总磷,水溶性盐的总含量,有效钾,土壤有机质,通过蓝藻结壳到地衣结壳再到苔藓结壳的演替,有效磷逐渐增强。串联,随着生物演替的进行,土壤细菌多样性增加,但真菌多样性下降。共鉴定出32个细菌门和11个真菌门,这些也发生在其他沙漠生态系统中。在那些类群中,变形杆菌和蓝细菌的相对丰度显着增加和减少,分别,沿着蓝藻外壳-地衣-苔藓外壳的演替梯度。然而,对于放线菌,氯氟菌,和酸杆菌它们的相对丰度变化明显呈驼峰形,从蓝藻壳到地衣壳的转变越来越多,然后随着地衣皮转移到苔藓皮而减少。在这个过程中,土壤性质的改善有效地增强了土壤细菌和真菌群落组成。总之,这些发现扩大了我们对高纬度生物锈病演替过程中土壤微生物性质如何变化的理解,寒冷的沙地生态系统。
Biological soil crusts (biocrusts) are considered \"desert ecosystem engineers\" because they play a vital role in the restoration and stability maintenance of deserts, including those cold sandy land ecosystems at high latitudes, which are especially understudied. Microorganisms participate in the formation and succession of biocrusts, contributing to soil properties\' improvement and the stability of soil aggregates, and thus vegetation development. Accordingly, understanding the composition and successional characteristics of microorganisms is a prerequisite for analyzing the ecological functions of biocrusts and related applications. Here, the Hulun Buir Sandy Land region in northeastern China-lying at the highest latitude of any sandy land in the country-was selected for study. Through a field investigation and next-generation sequencing (Illumina MiSeq PE300 Platform), our goal was to assess the shifts in diversity and community composition of soil bacteria and fungi across different stages during the succession of biocrusts in this region, and to uncover the main factors involved in shaping their soil microbial community. The results revealed that the nutrient enrichment capacity of biocrusts for available nitrogen, total nitrogen, total phosphorus, total content of water-soluble salt, available potassium, soil organic matter, and available phosphorus was progressively enhanced by the succession of cyanobacterial crusts to lichen crusts and then to moss crusts. In tandem, soil bacterial diversity increased as biocrust succession proceeded but fungal diversity decreased. A total of 32 bacterial phyla and 11 fungal phyla were identified, these also known to occur in other desert ecosystems. Among those taxa, the relative abundance of Proteobacteria and Cyanobacteria significantly increased and decreased, respectively, along the cyanobacterial crust-lichen-moss crust successional gradient. However, for Actinobacteria, Chloroflexi, and Acidobacteria their changed relative abundance was significantly hump-shaped, increasing in the shift from cyanobacterial crust to lichen crust, and then decreasing as lichen crust shifted to moss crust. In this process, the improved soil properties effectively enhanced soil bacterial and fungal community composition. Altogether, these findings broaden our understanding about how soil microbial properties can change during the succession of biocrusts in high-latitude, cold sandy land ecosystems.