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Biological soil crusts (BSCs) play a fundamental role in desert ecosystems by stabilizing soil, cycling nutrients, and retaining moisture. However, the assembly processes governing bacterial communities within BSCs remain largely unknown. This study aimed to reveal the spatiotemporal variations in the bacterial community diversity, co-occurrence patterns, and ecological assembly processes of BSCs and their underlying soils across different desert and seasonal conditions. We systematically analyzed the spatial differences in the bacterial diversity, co-occurrence networks, and community assembly processes of BSCs and their underlying soils using samples collected at various soil depths from different BSC types in different deserts. We discovered that BSC type and soil depth were the primary factors driving bacterial community assembly, while seasonal effects were weaker and more indirect, and mainly regulated community dynamics through changes in resource availability and environmental conditions. The underlying soils of moss- and lichen-BSCs exhibited higher bacterial diversity and richness than those of algae BSCs. In contrast, cyano-BSCs exhibited a lower diversity, but Cyanobacteria demonstrated the highest photosynthetic function. Among the different deserts, the community assembly of samples from the eastern Inner Mongolia deserts was largely influenced by environmental selection, whereas stochastic processes were more prominent in the central and western desert regions. A beta-nearest taxon index (beta NTI) analysis indicated that stochastic processes were dominant in surface BSC samples, while environmental selection played a stronger role in deeper layers. A co-occurrence network analysis revealed that surface BSC samples had a high degree of network connectivity, with those from moss- and lichen-BSCs being particularly high, and they also exhibited high modularity and local clustering that promoted the functional stability of the microbial communities. This study revealed the integrated effects of soil depth, BSC type, desert type, and resource availability on microbial community assembly in desert ecosystems. These findings provide a theoretical basis for the microbial management of BSCs and scientific insights to support restoration strategies in desert ecosystems.

期刊论文 2025-02-01 DOI: 10.3390/microorganisms13020446

Subsidence from coal mining is a major environmental issue, causing significant damage to soil structure. Soil microorganisms, highly sensitive to environmental changes, adapt accordingly. This study focused on four areas of the Burdai coal mine: a non-subsidence area (CK), half-yearly (HY), 1-year (OY), and 2-year (TY) subsidence areas. Using high-throughput sequencing and molecular ecological network analysis, we examined soil microbial community diversity and structure across these zones, exploring microbial community assembly and functional predictions. Results showed that compared to the control, subsidence areas experienced reduced soil water content, organic matter, available phosphorus, and alkaline nitrogen, with the lowest levels observed at 1 year. These values began to rise after 1 year, suggesting natural recovery after subsidence stabilized. Microbial communities were closely related to soil organic matter, water content, and alkaline nitrogen. At the 1-year mark, soil property changes significantly reduced microbial diversity, which then began to recover after 2 years. The microbial network during 1-year subsidence was simpler, with 102 nodes, 179 edges, and an average degree of 3.51, indicating that early subsidence was unstable, and the microbial community was still adapting. By 1 year, community structure and interactions had begun to stabilize. Stochastic processes played a key role in microbial variability during short-term subsidence.

期刊论文 2025-01-31 DOI: 10.1002/jobm.70002 ISSN: 0233-111X

Deinococcus species, noted for their exceptional resistance to DNA-damaging environmental stresses, have piqued scientists' interest for decades. This study dives into the complex mechanisms underpinning radiation resistance in the Deinococcus genus. We have examined the genomes of 82 Deinococcus species and classified radiation-resistance proteins manually into five unique curated categories: DNA repair, oxidative stress defense, Ddr and Ppr proteins, regulatory proteins, and miscellaneous resistance components. This classification reveals important information about the various molecular mechanisms used by these extremophiles which have been less explored so far. We also investigated the presence or lack of these proteins in the context of phylogenetic relationships, core, and pan-genomes, which offered light on the evolutionary dynamics of radiation resistance. This comprehensive study provides a deeper understanding of the genetic underpinnings of radiation resistance in the Deinococcus genus, with potential implications for understanding similar mechanisms in other organisms using an interactomics approach. Finally, this study reveals the complexities of radiation resistance mechanisms, providing a comprehensive understanding of the genetic components that allow Deinococcus species to flourish under harsh environments. The findings add to our understanding of the larger spectrum of stress adaption techniques in bacteria and may have applications in sectors ranging from biotechnology to environmental research.

期刊论文 2024-10-01 DOI: 10.1016/j.compbiolchem.2024.108161 ISSN: 1476-9271

Characterizing the effects of particle interaction and the influence of the fabric of granular materials is one of the primary challenges in studying the constitutive behavior of granular materials. The evolution of the fabric of granular materials and their response to applied stresses have been investigated extensively in the literature. Contact number is one of the most common metrics used to assess the evolution of the fabric of granular materials subjected to external loading. However, contact number is a limited metric as it incorporates only the effect of the particles in contact with a specific particle; it cannot be used to characterize the evolution of the fabric of granular materials at a mesoscale. A new metric that can incorporate the effect of particles in direct contact with a specific particle (as well as other particles within its vicinity) is much more powerful in characterizing the evolution of granular material fabric. Subgraph centrality (SC) is a complex network property that describes the change in the number of closed cycles in a network and represents a new metric for characterizing the contact network of the particles at the particle scale and mesoscale. 3D Synchrotron micro-computed tomography images (SMT) and SC were used to characterize the evolution of the fabric in five specimens, which were composed of two different types of silica sand particles subjected to axisymmetric triaxial loading. The effects of the specimens' initial density, confining pressure, kinematics of the particles, and particle morphology on the evolution of the contact network of the particles were investigated. The evolution of four node structures as one of the underlying fabric structures within the specimen was investigated to illustrate how the structure of the specimens was evolving and causing the change in the SC of the particles. Variation in the average SC of the specimens was correlated with their volumetric strain to demonstrate the relationship between the change in the contact structure of the particles and the constitutive behavior of sheared sand.

期刊论文 2024-05-01 DOI: 10.1016/j.compgeo.2024.106211 ISSN: 0266-352X

The cryosphere in the Himalaya-Karakoram (H-K) is widespread, and its services significantly affect the SDGs implementation in the region, in particular related to the 'No poverty' (SDG 1), 'zero hunger' (SDG 2), 'good health and well-being' (SDG 3), 'work and economic' (SDG 8) and 'partnership for the goals' (SDG 17). We here established the networks to illustrate the complex relationship of cryosphere services with national SDG priorities in the countries of H-K, including Afghanistan, Pakistan, India, China, Nepal and Bhutan. The cryosphere services contributing to the national SDG priorities and the key targets were elucidated in line with the centralities of the network. It was found that 'freshwater', 'clean energy', 'runoff regulation', 'climate regulation', 'research and education' and 'infrastructure and engineering' are the services that play critical roles in H-K, and they were then applied to assess the impact of cryosphere services on the national SDG priorities. We subsequently identified a set of principal indicators in relation to the key targets of national SDG priorities, which has the explanation up to 85% of six entry points (SEPs) to advance SDGs of each country in H-K. In conjunction with the centrality of the key targets to be contributed by the overall cryosphere services in the network for each country, the dependency of SEPs on the cryosphere services can be established through principal indicators in association with the national SDG priorities in H-K countries.

期刊论文 2022-03-01 DOI: http://dx.doi.org/10.3390/su14052532
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