Integrated assessment of the water environment has become widespread in many rivers, lakes, and reservoirs; however, aquatic organisms in freshwater are often overlooked in this process. Zooplankton, as primary consumers, are sensitive and responsive to changes in the water environment. Water and zooplankton samples were collected on-site at Shanxi Reservoir quarterly to determine 12 water environmental indicators and to quantify the abundance of zooplankton of Cladocera, Copepoda and Rotifera by using the ZooScan zooplankton image-scanning analysis system, combined with OLYMPUS BX51 using machine learning recognition classification. The aim was to explore the relationship between water environmental factors and zooplankton through their spatial and temporal heterogeneity. Through principal component analysis, redundancy analysis and cluster analysis, variations in the factors driving zooplankton population growth in different seasons could be identified. At the same time, different taxa of zooplankton can form clusters with related water environmental factors during the abundant water period in summer and the dry water period in winter. Based on long-term monitoring, zooplankton can be used as a comprehensive indicator for water environment and water ecological health evaluation, as well as providing scientific support for regional water resources deployment and management.

Weirs are often constructed on mountainous rivers because of their low construction costs and their ability to provide irrigation and facilitate landscaping, yet there is little research on how fish habitat quality in mountainous rivers responds to weir distribution. This study categorized the distribution characteristics of weirs on typical reaches according to their sinuosity and calculated the corresponding habitat suitability index (HSI) and weighted usable area (WUA) under various discharge conditions using a coupled MIKE21 and habitat suitability model. Then, the relationship between the distribution characteristics of weirs and the quality of fish habitats under different discharge conditions was analyzed. The results show that weirs in mountainous rivers can affect the habitat suitability of the rivers, but this effect is closely related to discharge conditions and layout mainly because the key hydraulic factors that determine habitat quality for different sinuous reaches vary under different discharge conditions. This study found that in high-sinuosity rivers with high discharge conditions, water depth is the key factor determining the quality of fish habitats, so weirs can improve habitat quality by improving the suitability of downstream water depth. However, in other conditions, velocity is the key factor determining habitat quality, in which case weirs cannot improve habitat quality and can even degrade it. Therefore, other methods of improving velocity are needed to enhance habitat quality. The results of this study provide a reference for the protection of fish habitats in mountainous river channels and the determination of suitable locations for weir construction.

Thermophilic cyanobacteria are key models for thermotolerance and a promising source of thermophilic bioresources. Yet the subcellular basis of their stress resilience remains poorly resolved. Here, we focus on intracellular polyphosphate (polyP)-rich granules, termed “stabilisomes,” which have been implicated in stress adaptation. The lack of a high-purity, structure-preserving isolation method has been a major technical bottleneck hindering the elucidation of this resilience mechanism. This study describes a robust, structure-preserving purification strategy, boosting the granule-to-protein yield by over 10,000-fold compared with conventional methods. The specificity and structural integrity of this method are supported by the specific enrichment of complex proteomic (937 proteins) and metabolomic (1076 metabolites) signatures. Building on this, subsequent quantitative analysis across cyanobacteria at 7 hot spring sampling sites revealed a conserved core chemical composition dominated by polyphosphate (~21–36%), proteins (~10–20%), amino acids (~7–18%), and lipid components (~12–21%). The variability in abundance across species suggests a dynamic adjustment of these stabilizing components consistent with specific micro-environmental conditions. This work provides a robust bioseparation platform for prokaryotic organelles, offering a critical tool for investigating cyanobacterial resilience and developing novel biomaterials.

Riparian zones of reservoirs are dynamic hotspots for carbon cycling, yet the response mechanisms of soil organic carbon (SOC) fractions to varying hydrological regimes remain incompletely understood. This study investigated the spatial distribution and driving factors of particulate (POC) and mineral-associated organic carbon (MAOC) across a hydrological gradient in the large subtropical Shanxi Reservoir (watershed area: 1,529 km²), China. Soil samples (Haplic Acrisols) were collected in July 2024 from four zones ranging from permanently inundated to not inundated, with SOC separated into two fractions (POC and MAOC) via particle-size fractionation and analysed using a randomised complete block design in which each of the ten transects spanned all four zones. The results showed that while POC increased more than four-fold from the inundated to the not inundated zone, MAOC exhibited no significant zonal variation. Consequently, the POC/MAOC ratio rose monotonically from 0.3 to 0.8, and inundation zone explained 96% of its variance but only 41% of that in total SOC, demonstrating that inundation frequency regulates carbon compositional structure more strongly than total carbon content. Contrary to conventional mineral protection paradigms, clay and silt contents were negatively correlated with all carbon fractions due to hydrodynamic sorting. Furthermore, carbon composition was governed overall by long-term inundation regimes rather than instantaneous soil moisture states. These findings highlight that the more active and labile carbon pool (i.e. POC) is highly vulnerable to changing hydrological regimes while MAOC as a more stable pool is less affected. The decoupling of clay from carbon stabilisation challenges traditional models in dynamic environments and suggests that reservoir water-level management is an underexplored but critical lever for regulating the stability of riparian carbon pools at the terrestrial-aquatic interface.

Phosphorus (P) availability in alkaline soils is constrained by the immobilization of legacy P, particularly through calcium phosphate precipitation. We used a confined soil–plant microcosm to examine how expression of the polyphosphate kinase gene (ppk) is associated with legacy P utilization in rice (Oryza sativa L.). We compared ppk-expressing transgenic rice (ETR) carrying single-copy (ETRS) and double-copy (ETRD) insertions with their isogenic wild type (WT), without P fertilization. Both transgenic lines had higher root organic acid release and acid phosphatase activity on day 30 and greater plant P acquisition by day 60 than WT; soil pH declined to a greater extent. On day 30, transgenic roots released more oxalate and malate, and their exudates mobilized more soil P than WT exudates in a separate incubation assay. These traits corresponded to greater depletion of the operationally defined HCl-P and NaOH-P pools. Bacterial profiles and PICRUSt2 predictions were descriptive because one pooled library per genotype precluded tests of genotype effects. Diffusive gradients in thin films (DGT) measurements revealed greater rhizosphere labile P in the ETRD early in plant growth, followed by a decline as plant P concentrations increased. This pattern was consistent with an early increase in P supply followed by plant-driven depletion. Net P acquisition in ETRD was 2.55 times that in WT, and ETRD exhibited 53% greater root biomass, while ETRS showed intermediate responses. Collectively, these results link enhanced plant P acquisition to greater P release in exudate incubation assays and higher acid phosphatase activity within this confined system.