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Water quality evaluation is the most direct and quantitative description of a reservoir water environment. Due to the lack of biological factor evaluation in water quality evaluation at present, the conventional pollution index evaluation system was used to evaluate water quality and the correlation between the evaluation indexes and the concentration of cyanobacteria was studied. After determining the correlation, a novel calculation method using the cyanobacteria pollution index was determined by principal component analysis (PCA). The results showed that the eutrophication index and nitrogen phosphorus index of the water body were high. Biological pollution in reservoirs cannot be ignored. The correlation between eutrophication index and cyanobacteria concentration was weak (Pearson correlation = 0.242). For the reservoir, it was necessary to establish a special cyanobacteria pollution index. Five variables were used for the cyanobacteria pollution index calculation by the PCA method. The total variance of the two main components was 77.107%, which reflected most of the data information. In the reservoirs of other areas, similar parameters can also be selected to calculate the cyanobacteria pollution index. This research provides a reference for the biological factor evaluation of similar reservoirs in the world. HIGHLIGHTS A special daily water quality test was used in order to make an accurate judgment on water quality.; PCA was selected to establish the calculation method of the cyanobacteria pollution index by considering the relationship between cyanobacteria concentration and other water quality factors.; This research provides a reference for similar areas of the world on water quality evaluation of reservoirs.

The effective integration of aerial remote sensing data and ground multi-source data has always been one of the difficulties of quantitative remote sensing. A new monitoring mode is designed, which installs the hyperspectral imager on the UAV and places a buoy spectrometer on the river. Water samples are collected simultaneously to obtain in situ assay data of total phosphorus, total nitrogen, COD, turbidity, and chlorophyll during data collection. The cross-correlogram spectral matching (CCSM) algorithm is used to match the data of the buoy spectrometer with the UAV spectral data to significantly reduce the UAV data noise. An absorption characteristics recognition algorithm (ACR) is designed to realize a new method for comparing UAV data with laboratory data. This method takes into account the spectral characteristics and the correlation characteristics of test data synchronously. It is concluded that the most accurate water quality parameters can be calculated by using the regression method under five scales after the regression tests of the multiple linear regression method (MLR), support vector machine method (SVM), and neural network (NN) method. This new working mode of integrating spectral imager data with point spectrometer data will become a trend in water quality monitoring.

At present, there are few studies on known bacterial species and even less on fungi in biological algae control technology. In this paper, the green eutrophic shallow water lake Scenedesmus quadricauda (Turpin) was used as the research object, and white rot fungi, which has a high removal effect on water pollutants, algae and biological toxins, was used for algae control. The extent of the removal effect, physiological characteristics and the internal functional groups of the algae cells in the white rot fungi solution, the supernatant of the white rot fungi solution after centrifugation and the sterilized white rot fungi solution were investigated. The results showed that the best algae solubilization effect of the algae control system was achieved at 250 mg/L, with 8 mg/L of dissolved oxygen and a hydraulic retention time of 48 h. The average algae lysis rate was 85.48%, the average dehydrogenase activity reduction rate was 59.23%, the average soluble protein reduction rate was 65.16% and the average malondialdehyde content increased to 0.128 umol/L. After treatment with the white rot algae control system, the spatial structure of the Turpin cells was severely disrupted, and significant lysis occurred within the algal cells, forcing the release of intracellularly soluble substances, and reducing the dehydrogenase activity of the Turpin cells, thus inhibiting the growth activity of the algae cells. A further reduction in the soluble protein content reduces the nutrients required for the growth of Turpin, exacerbating the rate of reduction in the physiological metabolic activity of the Turpin cells and, ultimately, the inhibition or killing of the algal cells. The results of this research may provide theoretical guidance for the microbial control of water eutrophication; however, whether there will be secondary pollution after the algae dissolution of this process is worthy of further study.

Different land uses have varying degrees of impact on nitrogen transport in the catchments. In recent decades, rapid urbanization has dramatically changed the Earth&rsquo, s land surface, which may cause excessive nitrogen losses and a negative influence on the environment. In the long-term scale, it is important to explore how the nitrogen transport responds to land use change and its effects on aquatic habitats. In this study, the water and sediment samples were collected from northern Taihu Basin, and nine periods of land use data were obtained using the techniques of supervised classification. Results revealed that the proportion of farmland area decreased from 28.33% to 7.09%, while that of constructed land area increased from 23.85% to 61.72% during 1990&ndash, 2017. Most of the constructed land originated from farmland, which makes it the dominant land use type due to rapid urbanization. In spatial distribution, high total nitrogen (TN) losses regions remain distributed over constructed land and farmland, which may aggravate the trend of local water quality deterioration. Of these regions, constructed land was the dominant contributor (46.29%&ndash, 63.62%) of TN losses from surface runoff. In temporal variation, the TN losses of runoff decreased by 47% from 175 t N&middot, a&minus, 1 in 1990. However, they increased by 2.91% from 75.28 t N&middot, 1 after 2013 with rapid population growth and high fertilizer application (&gt, 570 kg&middot, ha&minus, 1). The nitrogen load in sediments also has a significant response (t = 2.43, p = 0.02) to the effects of land use change on the overlying water, indicating that the role of nitrogen in the sediment as a source and/or sink to the waterbody may change frequently. Given the increasing accumulation of nitrogen loads in highly urbanized regions, water quality would cause more aggravation in the long-term without reasonable land management measures.

Water eutrophication caused by agricultural production has become one of the most important factors that impede sustainable rural environmental governance in China. As a result, the Chinese central and local governments want to reduce the use of nitrogen and phosphorus fertilizer and gain socioeconomical profit simultaneously by promoting crayfish and rice integrated system (CRIS) in the rural areas with abundant water resources. In this article, we investigated whether CRIS in Qianjiang, Hubei, the origin place of the system in China, contributes to fulfilling the governments&rsquo, expectations. We found that CRIS efficaciously cuts the fertilizer rate in rice production and boosts farmers&rsquo, incomes because crayfish has a demand for water quality and holds a large internal market requirement. However, higher profit encourages farmers to expand crayfish production and thus discourages the initiatives in rice production. The area of the ditch for crayfish production expands ceaselessly and exceeds the limit of regulation of CRIS. As a result, the CRIS in the areas has emerged as a practice of aquaculture but in farmland. This is a regulatory gap. The input&ndash, output analysis of CRIS by material balance method can also reveal that excessive feed for crayfish has become a new source of agricultural pollution. Beyond that, due to the changed irrigation system and increased water exchange frequency of CRIS, the pollution has transformed from passive distribution to active, which will increase the risk of water eutrophication on a large area.

Population structure and genome-wide linkage disequilibrium (LD) were investigated in 192 Hordeum vulgare accessions providing a comprehensive coverage of past and present barley breeding in the Mediterranean basin, using 50 nuclear microsatellite and 1,130 DArT markers. Both clustering and principal coordinate analyses clearly sub-divided the sample into five distinct groups centred on key ancestors and regions of origin of the germplasm. For given genetic distances, large variation in LD values was observed, ranging from closely linked markers completely at equilibrium to marker pairs at 50 cM separation still showing significant LD. Mean LD values across the whole population sample decayed below r2 of 0.15 after 3.2 cM. By assaying 1,130 genome-wide DArT markers, we demonstrated that, after accounting for population substructure, current genome coverage of 1 marker per 1.5 cM except for chromosome 4H with 1 marker per 3.62 cM is sufficient for whole genome association scans. We show, by identifying associations with powdery mildew that map in genomic regions known to have resistance loci, that associations can be detected in strongly stratified samples provided population structure is effectively controlled in the analysis. The population we describe is, therefore, shown to be a valuable resource, which can be used in basic and applied research in barley.