Soil phosphorus accumulation in mountainous alpine grassland contributes to positive climate change feedback via nitrifier and denitrifier community.

Mountainous alpine ecosystems are sensitive to global change, where soil nutrient content would potentially vary under current climate change background, and thus possibly influence the activity of nitrifiers and denitrifiers, as well as N2O emissions. However, within mountainous alpine ecosystems, the potential variation of soil nutrients under current global change and the consequence to N2O emission from nitrification and denitrification are still unclarified, hampering a comprehensive understanding of the feedback mechanisms between the nitrogen cycle and climate change. In order to fill this knowledge gap, we selected alpine grasslands at three different elevations and investigated the distribution and environmental drivers of nitrifiers and denitrifiers. The results showed that the lowest elevation site tended to have higher total phosphorus (TP) accumulation within the topsoil. The abundance of functional groups, emission of CO2 and N2O, and the N2O/CO2 ratio showed a decreasing trend along elevation. TP was the greatest influence on denitrifier composition (nosZ/narG and nirS/nirK ratios) and considerably influenced nitrifier composition (AOA/AOB ratio), and was significantly correlated to the N2O/CO2 ratio. In microcosms of soils from the highest elevation site, TP addition decreased the ratios of nosZ/narG, nirS/nirK, and AOA/AOB, and increased N2O/CO2 ratio and N2O emission, thus contributing to positive climate change feedback. This study indicates the potential for change within the nitrifier and denitrifier communities under current climate change, and highlights the role TP plays in governing nitrification and denitrification in mountainous alpine ecosystems.

Effect of Perineum Block Anesthesia Combined with Unprotected Perineal Delivery on the Perineal Integrity Rate and Maternal-Infant Outcomes in Primiparas Taking Health Products Containing Traditional Chinese Medicine.

OBJECTIVE: The purpose of the study was to investigate the effect of perineum block anaesthesia combined with unprotected perineal delivery on the perineal integrity rate and maternal-infant outcomes in primiparas taking health products containing traditional Chinese medicine (TCM). METHODS: A total of 120 puerperae admitted to our hospital from July 2019 to July 2020 were selected as study subjects and divided into group A (n = 60) and group B (n = 60), according to the number table method. Both groups took health products containing TCM, and the puerperae in group A received perineum block anaesthesia combined with unprotected perineal delivery, while those in group B were treated with routine delivery combined with routine protected perineal delivery. After that, the effect of different delivery modes on the perineal integrity rate and maternal-infant outcomes in puerperae was analyzed by the comparison of delivery condition, perineal condition, and postpartum quality of life between the two groups. RESULTS: There were no significant differences in average age and other general data between the two groups (P > 0.05); the duration in first, second, and third stages of labor in group A was significantly lower than that in group B (P < 0.001); the Apgar score in group A was significantly higher than that in group B (P < 0.001); the number of puerperae with integrated perineum in group A was significantly higher than that in group B (P < 0.05), while the number of puerperae receiving episiotomy in group A was significantly lower than that in group B (P < 0.05); the quality of life score in group A was significantly higher than that in group B (P < 0.001); the incidence of maternal postpartum complications in group A was significantly lower than that in group B (P < 0.05). CONCLUSION: Perineum block anaesthesia combined with unprotected perineal delivery can effectively shorten maternal labor duration, improve perineal integrity rate, and reduce laceration of perineum, with a significant therapeutic effect, which is worthy of application and promotion.

Microbial Community Structure in the Sediments and Its Relation to Environmental Factors in Eutrophicated Sancha Lake.

To study the microbial community structure in sediments and its relation to eutrophication environment factors, the sediments and the overlying water of Sancha Lake were collected in the four seasons. MiSeq high-throughput sequencing was conducted for the V3-V4 hypervariable regions of the 16S rRNA gene and was used to analyze the microbial community structure in sediments. Pearson correlation and redundancy analysis (RDA) were conducted to determine the relation between microbial populations and eutrophic factors. The results demonstrated four main patterns: (1) in the 36 samples that were collected, the classification annotation suggested 64 phyla, 259 classes, 476 orders, 759 families, and 9325 OTUs; (2) The diversity indices were ordered according to their values as with summer > winter > autumn > spring; (3) The microbial populations in the four seasons belonged to two distinct characteristic groups; (4) pH, dissolved oxygen (DO), total phosphorus (TP), and total nitrogen (TN) had significant effects on the community composition and structure, which further affected the dissolved total phosphorus (DTP) significantly. The present study demonstrates that the microbial communities in Sancha Lake sediments are highly diverse, their compositions and distributions are significantly different between spring and non-spring, and Actinobacteria and Cyanobacteria may be the key populations or indicator organisms for eutrophication.