Drivers of Spatiotemporal Eukaryote Plankton Distribution in a Trans-Basin Water Transfer Canal in China

Planktonic eukaryotes are important components of aquatic ecosystems, and analyses of the whole eukaryotic planktonic community composition and function have far-reaching significance for water resource management. We aimed to understand the spatiotemporal variation and drivers of eukaryotic plankton distribution in the Middle Route Project of the South-to-North Water Diversion in Henan Province, China. Specifically, we examined planktonic assemblages and water quality at five stations along the canal and another one located before the dam in March, June, September, and December 2019. High-throughput sequencing revealed that the eukaryotic plankton community was primarily composed of 53 phyla, 200 genera, and 277 species, with Cryptophyta, Ciliophora, and norank_k_Cryptophyta being the dominant phyla. Redundancy analysis of the eukaryotic community and environmental factors showed that five vital factors affecting eukaryotic plankton distribution were oxidation-reduction potential, nitrate nitrogen, pH, total phosphorus, and water flow velocity. Furthermore, the geographical distribution of eukaryotic communities was consistent with the distance decay model. Importantly, environmental selection dominantly shaped the geographical distribution of the eukaryotic community. In summary, our study elucidates the ecological response of planktonic eukaryotes by identifying the diversity and ecological distribution of planktonic eukaryotes in trans-basin diversion channels

Unusual grain-size effects on tensile deformation behavior of twinning-induced plasticity steel with low Mn content

In this work, the effects of grain refinement on the tensile properties, dynamic strain aging (DSA) and twinning behavior of Fe–16Mn-0.6C steel, which has relatively low manganese content, were investigated using a room-temperature monotonic tensile test, OM, XRD, EBSD and TEM. Results show that the yield strength, tensile strength and elongation of the steel increase with the decrease of grain size. Grain refinement can significantly increase the serration amplitude and local strain concentration of DSA, thereby enhancing the DSA-strengthening effect. The microstructure observations show that with the formation of plentiful twins, the twinning capacity of coarse-grained steel is exhausted prematurely at initial strains. Although the twinning behavior of fine-grained steel is retarded in the early stage of deformation, a large number of fine and dense twinning structures can be produced continuously at high strains. This unique twinning behavior and enhanced DSA in the fine-grained steel maintain the strain-hardening capacity of the steel, which delays the plastic instability and hence brings about simultaneous increases in strength and ductility

Organophotoredox-catalyzed intermolecular formal Grob fragmentation of cyclic alcohols with activated allylic acetates

We have developed an efficient method that employs organophotoredox-catalyzed relay Grob fragmentation to facilitate the smooth ring-opening allylation of cyclic alcohols in an environmentally friendly manner. This protocol directly incorporates a wide spectrum of cyclic alcohols and activated allylic acetates into the cross-coupling reaction, eliminating the need for metal catalysts. The process yields a variety of distally unsaturated ketones with good to excellent outcomes and stereoselectivity, while acetic acid is the sole byproduct.We gratefully acknowledge financial support from the National Natural Science Foundation of China (21702108), the Natural Science Foundation of Jiangsu Province, China (BK20211257), and the Six Talent Peaks Project in Jiangsu Province (YY-033)

Research and Application of Supersaturated Dissolved Oxygen Technology Combined with Magnetization Technology in the Improvement of Water Quality: Taking the South-to-North Water Diversion Project of China as a Pilot Project

Supersaturated dissolved oxygen and magnetization (SDOXM) technology is a composite technology that combines supersaturated dissolved oxygen with water magnetization technologies. Compared with conventional water purification technology, the advantages introduced by such technology include obvious and efficient improvement in purified water quality without adding any chemicals, removing sludge and changing the original function of the river. In this study, taking the Middle-Route (MR) of the South-to-North Water Diversion Project of China (SNWDPC) as a pilot project, the effects of the SDOXM composite process on microbial activity, phytoplankton community structure, and removal efficiency of the main nutritional indexes in the canal of the MR were evaluated. Aiming at static and flowing water bodies, this study was divided into two parts: static and dynamic experiments (two groups: a group with artificial aquatic plants and another group without artificial aquatic plants). The performance of the SDOXM system was assessed by monitoring the organic matter removal as well as the relative light unit (RLU) of ATP, changes in the community structure of phytoplankton, and the effects of artificial aquatic plants as a biofilm carrier on organic matter removal and microbial activity. During the study period, SDOXM technology was able to increase the concentration of dissolved oxygen (DO) in water and maintained the state of supersaturation for more than three days. The removal effect of organic matter from water was obvious. The community structure of phytoplankton changed from the Bacillariophyta-Cyanophyta type to the Bacillariophyta-Cyanobacteria type. Finally, the introduction of artificial aquatic plants has contributed to the improvement in water quality. Therefore, SDOXM technology can be used as a new water quality improvement technology to enhance the self-restoration ability of a river natural ecology

Genetic diversity of 23 STR loci of the Guizhou Tujia ethnic minority and the phylogenetic relationships with 22 other populations

Background Short tandem repeats (STR) are highly polymorphic DNA markers utilised in forensic personal identification and human population genetic research. Guizhou Tujia is one of the ancient minority groups in southwest China, however, the population has not been studied using the highly discriminating 23 STR Huaxia Platinum Kit. Aim To obtain genetic data from 23 autosomal STRs in Guizhou Tujia and examine the population’s relationship with others. Subjects and methods A total of 480 individuals from the Guizhou Tujia population were analysed using 23 STR loci of Huaxia Platinum Kit. Allele frequencies and forensic parameters were estimated. Population genetic relationships were calculated by Nei’s genetic distances and visualised using a variety of biostatistical methods. Results A total of 264 alleles were found, with allelic frequencies ranging from 0.0010 to 0.5104. The combined discrimination power (CDP) and the combined probability of paternity (CPE) of 23 STR loci were 0.9999999999999999999999999996 and 0.999999999710422, respectively. Guizhou Tujia showed closer genetic relationships with Hubei Tujia, Guizhou Gelao, and Guizhou Miao than with other populations. Conclusion We first obtained the population genetic data of Guizhou Tujia using the 23 STR system and demonstrated its value in forensic applications. Comprehensive population comparisons showed an evident genetic affinity pattern between populations that are geographically, ethnically and linguistically related

Succession and Driving Factors of Periphytic Community in the Middle Route Project of South-to-North Water Division (Henan, China)

The Middle Route Project of the South-to-North Water Diversion is an artificially independent system that does not connect to other surface waters. Excessive periphyton proliferation causes a series of environmental problems in the canal. In this study, the periphyton community and environmental factors on the left and right banks of the canal in the algal growing area were investigated and sampled six times (June, September, and November of 2019 and 2020). The succession pattern of the attached organism community in the artificial canal was analyzed, and the key factors affecting the algal community were analyzed using RDA and GAM. The results showed that the seasonal variability of the environmental factors was more significant than the spatial variability. A total of 114 taxa of periphytic algae were found, belonging to seven phyla and 69 genera, and mainly composed of Bacillariophyta. Species richness was ranked as Bacillariophyta (60 taxa), Chlorophyta (31 taxa) and Cyanobacteria (15 taxa), and higher in autumn than in summer. The dominant taxa were Cymbella sp., Fragilaria sp., Navicula sp. and Diatoma sp. The abundance of periphytic algal varied from 0.07 × 105 to 8.99 × 105 ind./cm2, with trends similar to that of species richness. The redundancy analysis and generalized additive model showed that water temperature and nutrient concentration were the key factors influencing the structure of the algal community, followed by discharge rate and velocity, which were the determinants of the spatial and temporal patterns of the algal community. In view of the influence of discharge and velocity on the structure of algal communities, it is suggested that ecological scheduling could be used to regulate the structure of the algal community on the canal wall in the operation of later water division projects to ensure the safety of water division

Driving Factors of Total Organic Carbon in Danjiangkou Reservoir Using Generalized Additive Model

Dynamic changes in total organic carbon (TOC) concentration in lakes and reservoirs affect the functions of aquatic ecosystems and are a key component of water quality management, especially in drinking water sources. The Danjiangkou Reservoir is the water source area of the Middle Route Project of the South-to-North Water Diversion in China. Its water quality is of critical importance to the safety of water diversion. TOC concentration and other environmental factors at 19 sampling sites in the Danjiangkou Reservoir were investigated quarterly during 2020–2021 to explore the differences at the spatio-temporal scales. A generalized additive model (GAM) was used to analyze the environmental factors correlated with the observed spatio-temporal variations of TOC concentration. The results showed that the comprehensive trophic level index (TLI) of the Danjiangkou Reservoir was under the state of intermediate nutrition, and the water quality was overall good. In terms of temporal patterns, TOC concentration was higher in both spring and summer and lower in other seasons. Spatially, TOC concentrations were found in descending order from the site of outlet, Han reservoir, entrance of reservoir, and Dan reservoir. The single-factor GAM model showed that TOC correlated with different environmental factors across spatio-temporal scales. Water temperature (WT), permanganate index (CODMn), and ammonia nitrogen (NH4+-N) were significantly correlated with TOC in autumn, but only total nitrogen (TN) and transparency (SD) were significant in winter. Spatially, WT, chemical oxygen demand (COD), NH4+-N, TN, and conductivity (Cond) correlated with TOC in the Dan reservoir, but WT, COD, NH4+-N, total phosphorus (TP), and chlorophyll a (Chl.a) were significant in the Han reservoir. The multi-factor GAM model indicated that the environmental factors correlated with TOC concentration were mainly WT, TN, Cond, CODMn, and TP, among which WT and Cond showed a significant linear relationship with TOC concentration (edf = 1, p < 0.05), while TN, CODMn, and TP had a significant nonlinear relationship with TOC concentration (edf > 1, p < 0.05). Comprehensive trophic level index (TLI) and TOC concentration revealed a highly significant correlation (R2 = 0.414, p < 0.001). Therefore, the GAM model could well explain the environmental factors associated with the spatio-temporal dynamics of TOC concentration, providing a reference for the evaluation of water quality and research on the carbon cycle in similar inland reservoirs

Graphene-assisted construction of electrocatalysts for carbon dioxide reduction

The electrochemical conversion of the greenhouse gas, carbon dioxide (CO2), to energy fuels and value-added chemicals presents one of the most valuable approaches to harvest pollutants and produce renewable energy. However, the stable molecular structure of CO2 and the sluggish reaction kinetics make CO2 reduction reaction (CO2RR) formidably challenging to achieve reaction rate and selectivity practical in industry. Graphene and its derivatives have been considered a group of intriguing materials to develop advanced CO2RR electrocatalysts due to their large specific surface area, remarkable electron transfer ability, superior stability, and easy tunability of the structure and surface properties. Herein, we comprehensively discuss the state-of-the-art electrocatalysts constructed with graphene and derivatives for active and selective CO2RR within the recent five years, mainly including the electrocatalysts with both metal-based (e.g., noble, non-noble, or combined thereof) and non-metal (e.g., doped, modified, defected, or composited) catalytic sites. To present the versatile, high-performance metal-based CO2RR electrocatalysts constructed with graphene, we further subdivide them according to the sizes, oxidation states, metal species synergies, dimensionalities, and versatility. Finally, we provide the challenges and perspectives in this emerging area of utilising CO2 to produce various carbon-based fuels and chemicals via graphene chemistry