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Land‐use change has significant influences on soil respiration (Rs) in terrestrial ecosystems. Soil microbes play critical roles in soil carbon cycling. Nevertheless, the specific mechanism of how changes in soil microbial properties are linked to the variation of Rs rate during land‐use change still remains poorly understood, especially in the Loess Plateau, China. Here, the characteristics of Rs rate and soil microbial community following the land‐use change from farmland to plantation/grassland were analyzed via an automated soil CO2 flux system and high‐throughput 16S rDNA gene sequencing. The afforestation altered soil microbial diversity and community composition, which was mainly explained by soil pH, temperature, organic matter, nitrate, alkali‐hydrolyzed nitrogen, and available phosphorus. The biomarkers of Bacteroidetes, Firmicutes, and Thaumarchaeota were found in farmland soil at the phylum level. The afforestation also significantly decreased Rs rate, which was closely related to Shannon's index, Simpson's index, and some microbial taxa, such as Bacteroidetes, Firmicutes, Nitrospirae, and Acidobacteria. Bacteroidetes, and Firmicutes were particularly expected to be important drivers of high Rs rate in farmland soil. Moreover, the microbial interaction was probably also an important factor affecting Rs rate. Our results indicate that the response of Rs to land‐use change depends on soil microbial community being regulated by soil physicochemical properties in the Loess Plateau, China. [ABSTRACT FROM AUTHOR]

Three species of the genus Synura from China are described here. Morphological observations and molecular phylogenetic analyses were conducted for three specimens collected at different locations in China. The described morphological features included cell size, scale size, spines, keels, and struts. Molecular analyses based on multiple genetic markers (SSU and LSU rDNA and internal transcribed spacer rDNA) were used to determine the phylogenetic positions of the three Synura species. Morphologically, specimen GZ201017 collected in Guizhou Province was characterized by a well-developed keel and lanceolate scales; specimen SX210304 collected in Shanxi Province was characterized by a less-developed keel and poor silicification; and specimen GD201126 collected in Guangdong Province was characterized mainly by spines with blunt ends or two small teeth on the tips. The morphotypes GZ201017, SX210304, and GD201126 corresponded to the original descriptions of Synura petersenii, S. glabra, and S. longitubularis, respectively. This discovery laid a foundation for the molecular phylogeny of the genus Synura and an enhanced understanding of Synura diversity and distribution in China. [ABSTRACT FROM AUTHOR]

A new species of freshwater alga, Chara zhengzhouensis, is described and illustrated based on material collected in a lake at Zhengzhou, in Henan Province, China. Phylogenetic analysis of sequence data from the 18s rDNA, rbcL, and atpB indicated the separation between C. zhengzhouensis and other species of the genus Chara. Additionally, from a morphological point of view, C. zhengzhouensis differs from another closely related species, C. connivens, in its diplostichous cortex and corticate or ecorticate in based segments of branchlets. Therefore, the results based on both morphological observation and molecular evidence facilitated the proposal of this new species—C. zhengzhouensis. It represents another species in the charophyte diversity in China and the description of this new species provides more molecular data for phylogenetic analysis of the genus Chara. [ABSTRACT FROM AUTHOR]

The genus Lemanea is an evolutionally derived lineage of freshwater Rhodophyta which has a rare distribution. Morphological characterization and molecular phylogenetic analyses were conducted for a Lemanea specimen collected from Guilin, China, in this study. The results based on morphological observation and molecular evidence, including rbcL and SSU sequences, showed it was a new record of L. manipurensis Ganesan, West, Zuccarello et Rout in China. The specimen in this study was morphologically characterized by branches that were positioned in the lower part of the thallus, hair cells absent around the outer cortex, ellipsoidal and single carpospores at the top of the gonimoblast filaments and spermatangia formed in continuous wide rings on the thallus nodes. By comparing the morphology of specimens collected from Guilin, China, and the holotype specimen in India, it was found that the spermatangial shapes were variable among different populations. It was found that the presence or absence of hair cells around the outer cortex was not a reliable characteristic for the identification of the genus Lemanea based on a comparison between L. manipurensis collected in Guangxi and in India and another four Lemanea species previously recorded in China. The results of this study provided molecular evidence and a theoretical basis for molecular phylogenetic research on the genus Lemanea and enriched the species diversity and geographical distribution of Lemanea in China. [ABSTRACT FROM AUTHOR]

Eukaryotic microalgae are widespread in soil. They are generally considered to participate in soil development and the formation of the soil food chain. Interestingly, some microalgae can grow in heterotrophic mode. Therefore, it is a reasonable speculation that eukaryotic microalgae may participate in the process of soil respiration (Rs) via the heterotrophic metabolism of soil organic matter. Nevertheless, the mechanism is not well understood. Here, we investigated the eukaryotic microalgal community in farmland and plantation/grassland soil via high‐throughput sequencing focusing on the Loess Plateau, China. Chlorophyta, Chrysophyta, Cryptophyta, Bacillariophyta, Dinophyta, Xanthophyta, and Haptophyta were found in all samples. Nevertheless, the biomarker for farmland soil was affiliated to Chlorophyta and Xanthophyta, whereas the biomarker for plantation/grassland soil was affiliated to Chrysophyta. Moreover, the distribution of soil microalgae was strongly dependent on soil pH, organic matter, and nitrogen. In addition, afforestation significantly decreased Rs rate, which was significantly related to the soil microalgal community, especially 11 taxa of eukaryotic microalgae affiliating to Chlorophyta and Chrysophyta. Meanwhile, the interaction between microalgae and bacteria in farmland soil was stronger than that in plantation/grassland soil, which was also likely to affect Rs rate. These results suggest that beyond plants, soil eukaryotic microalgae are functionally significant but rarely considered participants of Rs. Therefore, they should be considered when investigating soil carbon cycling. [ABSTRACT FROM AUTHOR]

We present light and scanning electron microscopical observations on frustules of a new species of Clipeoparvus Woodbridge et al. from Tibet. Cells are small, lens-shaped to conical, have internally occluded areolae and lack any processes. The Tibetan species differs from Clipeoparvus anatolicus Woodbridge, E.J. Cox & Roberts, the only other known species of the genus described from Turkey, by the number, size and structure of the spines on the valve face. Two morphs were encountered, one bearing spines and the other without spines, and they can occur separately or in the same frustule. This phenomenon may be an example of Janus cells within this taxon. The biogeographic distribution of this taxon is discussed. [ABSTRACT FROM AUTHOR]

The combustion explosion of ordinary diesel is a global environmental problem. Green microalgae, which do not cause eutrophication, are a raw material that can be used to clean biodiesel. To increase lipid productivity, this study used a nitrogen deficient & mixotrophic (+Glucose) culture of lipid-producing microalgae Parachlorella kessleri TY from Shanxi Province, China. To examine the growth of P. kessleri TY, we measured dry weight, chlorophyll content, and chlorophyll fluorescence intensity under different culture conditions, in addition to the contents of neutral lipids, total lipids, and fatty acids, to examine its lipid accumulation ability. Cells were cultured in autotrophic, nitrogen deficient, mixotrophic (+Glucose), and nitrogen deficient & mixotrophic (+Glucose) conditions for 7 days. We found the growth of P. kessleri TY under nitrogen deficient & mixotrophic conditions was higher than that under the autotrophic and nitrogen deficient conditions, but lower than that under the mixotrophic (+Glucose) conditions. However, its lipid accumulation ability was significantly higher than that of control cultures. In conclusion, P. kessleri TY cultured under nitrogen-deficient and mixotrophic (+Glucose) conditions has significant lipid production capacity. Our results provide a theoretical basis for the use of microalgae as a raw material in the production of biodiesel, and promote the application of P. kessleri TY in large-scale production. [ABSTRACT FROM AUTHOR]

The conversion of cropland to plantation is important ecological engineering in the Loess Plateau, China. Moreover, the extent of cropland abandonment and fallow is gradually increasing in this area, which probably affects the soil bacterial composition. Therefore, we applied Illumina MiSeq sequencing targeting the V3–V4 region of the 16S rRNA gene to analyze the bacterial community from different land-use types (cropland, plantation, cropland fallow and abandonment). The results showed that the plantation soil had the highest bacterial diversity. Biomarkers that strongly differentiated land-use types were found. The plantation, cropland fallow and abandonment were primarily associated with Proteobacteria , Nitrospirae , Acidobacteria , Firmicutes and Verrucomicrobia. The dominant populations from different land-use types had high similarity at the genus level, but there were still significant differences on the relative abundance of bacteria among some populations. Moreover, Pearson's correlations indicated that soil available phosphorus (SAP), soil available K (SAK) and vegetation biomass were the important factors affecting the bacterial community. These results suggested that bacterial community structure differed among different land-use types, which was closely related to soil environmental factors, such as SAP and SAK. • The soil bacterial community with land-use change was investigated. • Biomarkers that strongly differentiated land-use change were found. • SAP, SAK and vegetation biomass had important effects on soil bacterial community. [ABSTRACT FROM AUTHOR]

The "Grain for Green" project has been considered an effective avenue to control soil erosion, improve vegetation coverage and prevent ecosystem degradation in the Loess Plateau of China. However, the effect of the project on the underlying microbial mechanism of soil nitrogen cycling is not well understood. In the present study, the effect of land-use change from cropland to plantations on soil microbial community and functional genes involved in the nitrogen cycle was investigated via metagenomic sequencing analyses. The abundance rather than the composition of functional genes for nitrification, denitrification, assimilatory and dissimilatory nitrogen reduction significantly changed during the conversion of cropland to plantations. The abundance rather than the composition of microorganisms involved in the nitrogen cycle also changed significantly. The effect on the abundance of functional genes and microorganisms was mainly related to changes in soil properties, such as organic matter, total nitrogen, available phosphorus, available potassium and pH. The observed changes likely decrease the potential of nitrification, denitrification and assimilatory nitrogen reduction in the soil of plantations. Our results demonstrate that land-use change from cropland to plantations significantly affects soil nitrogen cycling in the Loess Plateau of China. • Land-use change affects the abundance of nitrogen-cycling genes and microorganisms. • The effect is mainly related to changes in soil properties. • The potential of nitrification and denitrification is high in cropland soil. • The potential of assimilatory nitrogen reduction is high in cropland soil. [ABSTRACT FROM AUTHOR]

Understanding the relative impact sizes of environmental factors and nutrients on the high annual variation of phytoplankton abundance in eutrophic rivers is important for aquatic ecosystem management efforts. In this study, we used phytoplankton dynamic datasets in the eutrophic Fenhe River to show the variations and drivers of phytoplankton abundance under complex, fluctuating environmental conditions during 2012–2017. The temporal and spatial variations of nutrients in the river depicted that the total phosphorus (TP) concentration was higher in the wet season and in downstream. There were increases in total nitrogen (TN) concentration in the normal season and in upstream. The structural equation model (SEM) showed that the phytoplankton abundance increased during the wet season despite the decrease in the TN:TP ratio and was reduced upstream due to the highest TN:TP ratio. Among the environmental variables, water temperature (WT) was an important predictor and positively correlated temporally and spatially to phytoplankton. The interaction of nutrients with the phytoplankton community at different temperature levels indicated that different phytoplankton groups have different nutrient requirements. We can conclude that enhances in temperature and TP concentration will significantly increase phytoplankton abundance and dominance of cyanobacteria and green algae in the future, whereas there was insignificant effect on diatoms. These data indicated that temperature and TP content were the important abiotic factors influencing the phytoplankton growth of the water body, which could provide a reference for the evaluation of environmental alterations in the future. [ABSTRACT FROM AUTHOR]

• Loop-mediated isothermal amplification assay for prevalent human respiratory adenoviruses. • Coupling with instrument-free DNA extraction device facilitating treating clinical samples. • A diagnostic platform enabling reliable screening test in resource-limited settings. Three human adenovirus (HAdV) genotypes, HAdV-7, HAdV-14, and HAdV-55, emerged as the most prevalent variants in China over the past decade and caused both sporadic, fatal cases and frequent, large outbreaks. Early diagnosis is essential to control infections and endemics. Here, we established a loop-mediated isothermal amplification (LAMP) assay coupled with an instrument-free nucleic acid extraction device recently developed by our group; the assay could detect all the 3 prevalent HAdV genotypes. Specificity analysis showed no cross-reactivity with other common respiratory pathogens and the analytical sensitivity was as low as 10 copies/μL. All detection steps could be completed within 1 hour. The assay's performance was evaluated using clinical samples and compared with the gold standard RT-PCR method, showing highly consistent results. The LAMP assay developed here could be readily used in basic laboratory facilities and with minimal DNA extraction equipment, and as a reliable screening test in a resource-limited setting. [ABSTRACT FROM AUTHOR]

Large-scale, inter-basin water diversion projects have been developed to relieve water scarcity crisis and water pollution problems. Environmental status and ecosystem impacts are largely unknown for the Wanjiazhai Yellow River Diversion Project (YRDP-WJZ), a water body critical in northern China. In the current study, twelve hydrochemical indices (including Mn, Cu, Zn, Hg, Pb, NH 3 -N, COD-Mn, DO, BOD 5 , COD, TP, and TN) were collected from 2008 to 2017 based on multiple analytical approaches to understand environmental status and ecological risks. Human health risk and threats to aquatic organisms from heavy metals were assessed. Heavy metals have no regular spatial distribution. Biochemical parameters and nutrients pollute seriously in midstream and downstream, respectively. Hydrochemical indices suggested high levels of pollution in the midstream section. Water quality improved downstream of the Fenhe Reservoir, but total nitrogen and total phosphorus in the downstream section increased in recent years. The Canadian Council of Ministers of the Environment Water Quality Index (CWQI) suggested midstream water quality was poor in general, and 80% of annual calculations had a marginal grade. For aquatic organisms, ecological risks of Cu and Zn were high. For local residents, drinking water was generally safe, but continued monitoring is critical due to ongoing threats to water quality in these areas.

In this paper, the algal cell density of cyanobacteria, green algae, and diatoms and their responses to the hydrochemical factors were analyzed to reveal the structural characteristics of water quality in an urban river. A total of nine sampling sites from upstream to downstream was explored in our study. At each site, the density of algae was identified every week during the wet season (June-October) from 2012 to 2017, and in situ detection was used for the relative 11 hydrochemical variables. The temporal and spatial characteristics of 14 variables were analyzed using a heatmap coupled with the cluster analysis method. The trend of each parameter was analyzed using the smoothing method with locally weighted regression. The nonmetric multidimensional scaling method was employed to detect the temporal and spatial similarities among algae along hydrochemical gradients. The responses of algal density to hydrochemical variables were analyzed using a redundancy analysis. The results showed that the water temperature (W temp ), pH, dissolved oxygen (DO), cyanobacteria, and diatoms exhibited significant declining trends, and significant increasing trends were shown in the permanganate index, chemical oxygen demand, total nitrogen, ammonia nitrogen, and total phosphorus; the cyanobacteria exhibited certain differences with green algae and diatoms in summer and the downstream areas of the river. The temporal-spatial homogeneity of algal to hydrochemical variables showed the key influencing factors of W temp for cyanobacteria density, chlorophyll for green algae density, DO, and pH for diatoms. The results presented here are valuable for deepening our understanding of river ecosystem evaluations and effective environmental management, as well as an important reference for the sustainable development of aquatic biological resources.