Global climate change exerts profound effects on snow cover, with consequential impacts on microbial activities and the stability of soil organic carbon (SOC) within aggregates. Northern peatlands are significant carbon reservoirs, playing a critical role in mitigating climate change. However, the effects of snow variations on microbial-mediated SOC stability within aggregates in peatlands remain inadequately understood. Here, an in-situ field experiment manipulating snow conditions (i.e., snow removal and snow cover) was conducted to investigate how snow variations affect soil microbial community and the associated SOC stability within soil aggregates (> 2, 0.25-2, and < 0.25 mm) in a peatland of Northeast China. The results showed that snow removal significantly increased the SOC content and stability within aggregates. Compared to the soils with snow cover, snow removal resulted in decreased soil average temperatures in the topsoil (0-30 cm depth) and subsoil (30-60 cm depth) (by 1.48 and 1.34 degrees C, respectively) and increased freeze-thaw cycles (by 11 cycles), consequently decreasing the stability of aggregates in the topsoil and subsoil (by 23.68% and 6.85%, respectively). Furthermore, more recalcitrant carbon and enhanced SOC stability were present in microaggregates (< 0.25 mm) at two soil depths. Moreover, reductions in bacterial diversity and network stability were observed in response to snow removal. Structural equation modeling analysis demonstrated that snow removal indirectly promoted (P < 0.01) SOC stability by regulating carbon to nitrogen (C:N) ratio within aggregates. Overall, our study suggested that microaggregate protection and an appropriate C:N ratio enhanced carbon sequestration in response to climate change.

Antimony (Sb) pollution is becoming more prevalent due to human activities. Recently, biochar (BC) and modified biochar have been used to remediate polluted soils. Nevertheless, role of modified BC and microbes to mitigate adversities of Sb is not understood. This study evaluated the effects of iron-modified biochar (FMB) and bacteria (Ochrobactrum oryzae) on rice plant functioning, Sb bio-accessibility, and microbial community structure and diversity. The experiment consisted of different treatments; control, Sb stress (1200 mg kg-1), Sb stress (1200 mg kg-1) + FMB (2.5 %), Sb stress (1200 mg kg-1) + bacterial inoculation and Sb stress (1200 mg kg-1) + FMB (2.5 %) + bacterial inoculation. The combined FMB and bacteria increased photosynthetic pigments, antioxidant activities, osmolyte accumulation and reduced oxidative damage, electrolyte leakage (EL), and malondialdehyde (MDA), thereby leading to better growth and yield. Combined FMB and bacterial inoculation also enhanced soil nutrient availability, soil organic carbon (SOC), and soil enzymatic activities thereby reducing the soil antimony availability (46.12 %) and bio-accessibility of Sb (Sb-bio: 59.25 %). Moreover, co-applying BC and bacteria inoculation reduced Sb accumulation rice roots and grains which was associated with increased soil pH, SOC, and soil enzyme activity. Additionally, FMB and bacteria application increased the abundance of favorable bacteria including Proteobacteria, Gemmatimonadete, Firmicutes, Bacteroidota, Chloroflexi, Myxococcota and Parcubacteria which also helped to counteract the toxic impacts of Sb. Therefore, the combination of FMB and bacteria can increase rice production in Sb-polluted soils. These findings offer a way to develop environmentally friendly technologies to improve safer and sustainable rice production in Sb-contaminated soils.

Nanomaterials play a crucial role in various applications, but their environmental impact necessitates effective recycling strategies. This study investigates the effects of different ZnO nanoparticles (ZnO-NPs) sizes (0, 30, 50, and 90 nm) on Agrostis stolonifera, focusing on physiological and biochemical responses, root exudate, and microbial community structure. The results showed that the most optimal physiological and biochemical responses, including enhanced plant growth and increased activities of superoxide dismutase, peroxidase, and catalase, were observed at 50 nm ZnO-NPs. Agrostis stolonifera accumulated more ZnO-NPs at 30 nm, with Zn content in root and leaf tissues reaching 186 mg/kg and 294 mg/kg, respectively. Meanwhile, SEM-Mapping and TEM analyses confirmed the absorption and transport of ZnO-NPs within Agrostis stolonifera. Furthermore, root exudates analysis revealed an increase in the types of organic matter secreted by roots at 30 nm and 50 nm ZnO-NPs, while 90 nm ZnO-NPs had the opposite effect. 16S rRNA gene sequencing showed that the species diversity and uniformity of root microorganisms exhibited contrasting trends with increasing ZnO-NPs size, with roots exposed to 50 nm ZnO-NPs showed higher species richness than those exposed to 30 nm or 90 nm. However, beneficial microorganisms such as Bryobacter and Methylophilus were inhibited by 90 nm ZnO-NPs. This study provides novel insights into a potential ZnO-NPs recycling strategy in soil using Agrostis stolonifera, offering a means to mitigate nanoparticle-induced damage to soil and crops.

Perennial planting of kiwifruit can easily lead to soil quality deterioration. To mitigate the negative effects of long-term kiwi cultivation on the soil, spring wheat straw is used to return to the field. The results showed that the longer the duration of straw returning to the field, the more pronounced the effect on soil quality improvement. The contents of SOM, AP, TN, and Alkaline-N were significantly higher in the Y10 plot (10-year-old kiwifruit plot) than in the Y1 plot (1-year-old kiwifruit plot) and the Y6 plot (6-year-old kiwifruit plot). The contents of these nutrients are 189.16%, 110.91%, 98.65% and 41.03% higher than Y1, respectively. Straw returning increased soil nutrients and enzyme activities (S-NP, S-SC and S-CL) and reduced soil acidification. Straw-returning treatment also enriched beneficial microbial groups (Ascomycota, Basidiomycota, Streptophyta, Mucoromycota, etc.) and changed functional groups and cellulolysis related to environmental stress. PLS-PM analysis showed that the years of straw returning to the field affected soil microorganisms' composition and functional adaptability by affecting soil nutrients and enzyme activities. These findings provide a feasible way to solve the problem of soil quality damage caused by long-term planting of kiwifruit.

The frequency of forest fires has increased dramatically due to climate change. The occurrence of forest fires affects the carbon and nitrogen cycles and react to climate change to form a positive feedback mechanism. These effects further impact the distribution of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) and the soil microbial community structure. In addition, permafrost degradation can significantly affect the microorganisms in the soil. Based on these findings, this review examines the effects of fire intensity and post-fire recovery time on permafrost, the soil microbial community, MBC, MBN, and their interrelationships. This review demonstrated that (1) fires alter the condition of surface vegetation, reduce the organic layer thickness, redistribute snow, accelerate permafrost degradation, and even lead to permanent changes, where the restoration of the pre-fire state would require several decades or even centuries; (2) soil microbial community structure, soil MBC, and MBN negatively correlate with fire intensity, and the effects become more pronounced with increasing fire intensity; and (3) the structural diversity and stability of the soil microbial community were improved with time, and the amount of MBC and MBN increases as the years after a fire go by; it would still take more than ten years to recover to the pre-fire level. However, the relationship between permafrost degradation and soil microbes after forest fires is still unclear due to a lack of quantitative research on the mechanisms underlying the changes in soil microorganisms resulting from fire-induced permafrost degradation. Therefore, expanding quantitative studies and analyses of the mechanisms of interactions between forest fires, permafrost, and soil microorganisms can provide a scientific basis for understanding ecosystem carbon pools and dual-carbon targets in Arctic-boreal permafrost regions.

The present investigation aimed to analyze the community structure and its relationship with selected soil parameters in the Gangetic plains. In total, 60 soil samples were collected from the fields of vegetable crops at different pH. Thirty-nine soil-inhabited nematodes were isolated and identified to the species level where possible. The most prevalent nematodes encountered were Hoplolaimus indicus followed by Helicotylenchus californicus and Pratylenchus thornei with 66.67, 53.33, and 40.00% frequency, respectively. Prominence Value of H. indicus (271.62), H. californicus (115.87), and P. thornei (31.62) was higher as compared to other PPN species. The result indicated that there is a significant correlation between the plant-parasitic species and pH (e.g., Rotylenchus reniformis; r = 0.991). On the other hand, EC showed a significant negative correlation with R. reniformis (r = -0.965). However, organic carbon and sand percentage significantly correlated with PPN. Organic carbon was highly correlated (r = 1.00) with R. reniformis. In contrast, organic carbon showed a significant positive correlation with Rhabditis and no correlation with Mesodorylaimus. In conclusion, the high-producing regions suggested a considerable range of plant-parasitic and free-living nematodes, with the highest diversity in Baghpat (H' = 0.604 +/- 0.14). Therefore, further studies are required to evaluate the ecological and threshold level of damage by the PPN. Additionally, the current finding suggests that soil fertility in upper 'Gangetic plains' agricultural fields was reduced due to the high load of PPN infection. However, ecological indices could help assess the plant and soil health of all the regions in future investigations.

Under the background of climate change, freeze-thaw patterns tend to be turbulent: ecosystem function processes and their mutual feedback mechanisms with microorganisms in sensitive areas around the world are currently a hot topic of research. We studied changes of soil properties in alpine wetlands located in arid areas of Central Asia during the seasonal freeze-thaw period (which included an initial freezing period, a deep freezing period, and a thawing period), and analyzed changes in soil bacterial community diversity, structure, network in different stages with the help of high-throughput sequencing technology. The results showed that the alpha diversity of the soil bacterial community showed a continuous decreasing trend during the seasonal freeze-thaw period. The relative abundance of dominant bacterial groups (Proteobacteria (39.04%-41.28%) and Bacteroidota (14.61%-20.12%)) did not change significantly during the freeze-thaw period. At the genus level, different genera belonging to the same phylum dominated in different stages, or there were clusters of genera belonging to different phylum. For example, g_Ellin6067, g_unclassified_f_Geobacteraceae, g_unclassified_f_Gemmatimonadaceae coexisted in the same cluster, belonging to Proteobacteria, Desulfobacterota and Gemmatimonadota respectively, and their abundance increased significantly during the freezing period. This adaptive freeze-thaw phylogenetic model suggests a heterogeneous stress resistance of bacteria during the freeze-thaw period. In addition, network analysis showed that, although the bacterial network was affected to some extent by environmental changes during the initial freezing period and its recovery in the thawing period lagged behind, the network complexity and stability did not change much as a whole. Our results prove that soil bacterial communities in alpine wetlands are highly resistant and adaptive to seasonal freeze-thaw conditions. As far as we know, compared with short-term freeze-thaw cycles research, this is the first study examining the influence of seasonal freeze-thaw on soil bacterial communities in alpine wetlands. Overall, our findings provide a solid base for further investigations of biogeochemical cycle processes under future climate change.

High latitude regions are experiencing considerable winter climate change, and reduced snowpack will likely affect soil microbial communities and their function, ultimately altering microbial-mediated biogeochemical cycles. However, the current knowledge on the responses of soil microorganisms to snow cover changes in permafrost ecosystems remains limited. Here, we conducted a 2-year (six periods) snow manipulation experi-ment comprising ambient snow and snow removal treatments with three replications of each treatment to explore the immediate and legacy effects of snow removal on soil bacterial community and enzyme activity in secondary Betala platyphylla forests in the permafrost region of the Daxing'an Mountains. Generally, bacterial community diversity was not particularly sensitive to the snow removal. Seasonal fluctuations in the relative abundance of dominated bacterial taxa were observed, but snow removal merely exerted a significant impact on the bacterial community structure during the snow melting period and early vegetation growing season within two consecutive years, with a reduction in the relative abundance of Chloroflexi and an increase in the relative abundance of Actinobacteria, and no evidence of cross-season legacy effects was found. Moreover, snow removal significantly altered the soil enzyme activities in the snow stabilization period and snow melting period, with an increase in soil acid phosphatase (ACP) activity of snow melting period and a decrease in polyphenol oxidase (PPO) activity of snow stabilization period as well as beta-glucosidase (BG) activity of snow stabilization period and snow melting period, but this effect did not persist into the vegetation growing periods. The seasonal variations in bacterial community and enzyme activity were mostly driven by changes in soil nutrient availability. Overall, our results suggest that soil bacterial communities have rather high resilience and rapid adaptability to snow cover changes in the forest ecosystems in the cold region of the Daxing'an Mountains.

Permafrost degradation by global warming is expected to alter the hydrological processes, which results in changes in vegetation species composition and gives rise to community succession. Ecotones are sensitive transition areas between ecosystem boundaries, attract particular interest due to their ecological importance and prompt responses to the environmental variables. However, the characteristics of soil microbial communities and extracellular enzymes along the forest-wetland ecotone in high-latitude permafrost region remain poorly understood. In this study, we evaluated the variations of soil bacterial and fungal community structures and soil extracellular enzymatic activities of 0-10 cm and 10-20 cm soil layers in five different wetland types along environmental gradients, including Larix gmelinii swamp (LY), Betula platyphylla swamp (BH), Alnus sibirica var. hirsute swamp (MCY), thicket swamp (GC), and tussock swamp (CC). The relative abundances of some dominant bacterial (Actinobacteria and Verrucomicrobia) and fungal (Ascomycota and Basidiomycota) phyla differed significantly among different wetlands, while bacterial and fungal alpha diversity was not strongly affected by soil depth. PCoA results showed that vegetation type, rather than soil depth explained more variation of soil microbial community structure. beta-glucosidase and beta-N-acetylglucosaminidase activities were significantly lower in GC and CC than in LY, BH, and MCY, while acid phosphatase activity was significantly higher in BH and GC than LY and CC. Altogether, the data suggest that soil moisture content (SMC) was the most important environmental factor contributing to the bacterial and fungal communities, while extracellular enzymatic activities were closely related to soil total organic carbon (TOC), nitrate nitrogen (NO3--N) and total phosphorus (TP).

Glaciers retreating due to global warming create important new habitats, particularly suitable for studying ecosystem development where nitrogen is a limiting factor. Nitrogen availability mainly results from microbial decomposition and transformation processes, including nitrification. AOA and AOB perform the first and rate-limiting step of nitrification. Investigating the abundance and diversity of AOA and AOB is essential for understanding early ecosystem development. The dynamics of AOA and AOB community structure along a soil chronosequence in Tianshan No. 1 Glacier foreland were analyzed using qPCR and clone library methods. The results consistently showed low quantities of both AOA and AOB throughout the chronosequence. Initially, the copy numbers of AOB were higher than those of AOA, but they decreased in later stages. The AOB community was dominated by Nitrosospira cluster ME, while the AOA community was dominated by the soil and sediment 1. Both communities were potentially connected to supra- and subglacial microbial communities during early stages. Correlation analysis revealed a significant positive correlation between the ratios of AOA and AOB with soil ammonium and total nitrogen levels. These results suggest that variations in abundance and diversity of AOA and AOB along the chronosequences were influenced by ammonium availability during glacier retreat.