Archaeal communities change responding to anthropogenic and natural treatments of freeze-thawed soils.

The coverage of accumulated snow plays a significant role in inducing changes in both microbial activity and environmental factors within freeze-thaw soil systems. This study aimed to analyze the impact of snow cover on the dynamics of archeal communities in freeze-thaw soil. Furthermore, it seeks to investigate the role of fertilization in freeze-thaw soil. Four treatments were established based on snow cover and fertilization:No snow and no fertilizer (CK-N), snow cover without fertilizer (X-N), fertilizer without snow cover (T-N), and both fertilizer and snow cover (T-X). The research findings indicated that after snow cover treatment, the carbon, nitrogen, and phosphorus content in freeze-thaw soil exhibit periodic fluctuations. Snow covered effectively altered the community composition of bacteria and archaea in the soil, with a greater impact on archaeal communities than on bacterial communities. Snow covered improves the stability of archaeal communities in freeze-thaw soil. Additionally, the arrival of snow also enhanced the correlation between archaea and environmental factors, with the key archaeal phyla involved being Nanoarchaeota and Crenarchaeota. Further research showed that the application of organic fertilizers also had some impact on freeze-thaw soil, but this impact was smaller compared to snow cover. In summary, the arrival of snow could alter the archaeal community and protect nutrient elements in freeze-thaw soil, reducing their loss, and its effect is more pronounced compared to the application of organic fertilizers.

Biotic pathways of reciprocal responses between antibiotic resistance genes and inorganic nitrogen cycling genes in amoxicillin-stressed compost ecosystems.

This study explored the transformation of inorganic nitrogen, the expression levels of antibiotic resistance genes (ARGs), and the regulatory mechanisms of key species on ARGs and inorganic nitrogen cycling genes (INCGs) under different levels of amoxicillin (AMX) stress. High level of AMX inhibited the accumulation of NH4+-N, which increased by 531 % relative to the initial. Moreover, AMX to some extent increased the levels of nirS and nirK, which could potentially result in nitrogen loss and the accumulation of NO2-. Actinobacteria might serve as potential hosts for ARGs during sludge composting. This stress induced a complex response between INCGs and ARGs more complex due to key species. Under high-level AMX pressure, most species associated with ARGs likely derived from nitrogen cycling functional species. To conclude, high levels of AMX stress might lead to nitrogen cycling imbalance and the dissemination of antibiotic resistance genes in composting systems.

Fate of dissolved organic matter affected by oxytetracycline tolerant microorganisms during chicken manure composting.

This study explored the interaction among the components of dissolved organic matter (DOM), environmental factors and oxytetracycline (OTC) tolerant bacteria during chicken manure composting using Parallel Factor Analysis (PARAFAC) and 16S rRNA sequencing analysis. The results revealed that the OTC residues in chicken manure may affect the transformation between the protein-like component (C1) and humus-like component (C2 and C3) during composting. The transformation of DOM components under the OTC stress was indirect by affecting the microbial community activity. The OTC tolerant bacteria that still exist after the high temperature period of composting had a significant positive correlation between the humification process. The correlations of the dissolved organic carbon (DOC), total nitrogen (TN), and core OTC tolerant bacteria with DOM components, which enhanced the cooperative function of DOM component transformation. To clarify the influence of OTC residue on the humification process can promote the composting carbon fixation and improve composting quality.

Deciphering the turnover of bacterial groups in winter agricultural soils.

In winter, snowpack is an important driver of soil bacterial processes. Amending soil through the addition of organic compost has also been reported to affect soil properties and bacterial communities. However, the effects of snow and organic compost on soils have not been systematically researched and compared. To investigate the effects of these two activities on the succession of bacterial communities in the soil and on important soil nutrients, four treatment groups were established in this study: no snow without compost (CK-N), no snow with compost (T1-N), snow without compost (CK-X) and snow with compost (T1-X). Four representative time periods were also selected according to the extent of snow accumulation, including the first snow and melt. In addition, the compost pile was treated with fertilizer made from decomposing food waste. The results indicate that Proteobacteria was more affected by temperature and that fertilization increased its proportional abundance. The abundance of Acidobacteriota was increased by snow. Ralstonia could depend on nutrients provided by organic fertilizers, which prevented them from ceasing to breed at low temperatures, while snow cover was still able to reduce their survival. However, snowpack increased the abundance of RB41. Snow reduced the point and connectivity of the bacterial community and increased the association with environmental factors, especially the negative correlation with total nitrogen (TN); the prefertilizer application made the community network larger while maintaining association with environmental factors. Specifically, more key nodes in sparse communities after snow cover were identified by Zi-Pi analysis. The present study systematically assessed soil bacterial community succession in the context of snow cover and fertilizer application and interpreted the farm environment from a microscopic perspective through the winter. We found that snowpack affects TN through bacterial community succession. This study offers new insight into soil management.