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1.
Eutrophication resulting from nutrient enrichment decreases water quality and harms ecosystem structure and function, and its degree is significantly affected by land use in the catchment. Quantifying the relationship between eutrophication and land use can help effectively manage land use to improve water quality. Previous studies principally utilized land use quantity as an indicator to link water quality parameters, but these studies lacked insight into the impact of land use intensity. Taking the upper catchment of Miyun Reservoir as a case study, we developed a method of aggregating land use quantity and intensity to build a new land use indicator and tested its explanatory power on water quality. Six nutrient concentrations from 52 sub-watersheds covering the whole catchment were used to characterize the spatial distribution of eutrophication. Based on spatial techniques, empirical conversion coefficients, remote sensing data, and socio-economic statistical data, land use intensity was measured and mapped visually. The new land use indicator was calculated and linked to nutrient concentrations by Pearson correlation coefficients. Results demonstrated that our new indicator incorporating intensity information can quantify the different nutrient-exporting abilities of different land use areas. Compared to traditional indicators that only incorporate land use quantity, most Pearson correlation coefficients between the new indicator and water nutrient concentrations increased. This new information enhanced the explanatory power of land use on water nutrient concentrations, and so will be able to help us understand the impact of land use on water quality and guide decision making for better land use management. 相似文献
2.
耦合水量供给与水质净化的水生态服务供需关系的多尺度空间量化评估,有助于刻画和识别丰水区水质性缺水问题,并丰富水生态服务研究。在构建水量供给和水质净化服务供需评估方法的基础上,利用空间分析方法在现状情景基础上分别设置提升用水效率、改善土地管理方式和优化土地利用空间配置三种优化情景,并在栅格、子流域和县域三个尺度上开展基于水量供给和水质净化的水生态服务供需关系的定量评估,分别探讨了不同情景不同尺度下的水生态服务供需变化、空间响应及其机制特征。研究结果表明:(1)太湖流域的水量供需状况显著优于水质供需状况,节水能够有效改善流域内的水量赤字,而减量施肥和优化土地利用配置能够显著改善流域内的水质赤字。(2)多尺度的水量供给与水质净化服务供需解析,有助于精准识别不同尺度下亟需治理的关键区域。(3)水量赤字区主要集中在建设用地分布区域,耕地仍是引致水质赤字的主要原因,但随着尺度的逐渐增大,水质赤字区的建设用地面积也在不断增加。(4)优化土地利用结构方案是解决水质性缺水的最有效方法,但需要突破现有政策尤其是耕地保护政策的刚性约束,故耦合提升用水效率等方法是当前治理太湖流域“水质性缺水”问题首选措施。 相似文献
3.
Floodplain lakes are valuable to humans because of their various functions. An emerging public concern on lake eutrophication has heightened the need to assess and predict the trophic status in floodplain lakes, particularly for those with high spatial heterogeneity. In this study, combined multivariate statistical techniques and random forests model were used to characterize the water quality and trophic status of Poyang Lake. By classifying and characterizing seasonal water samples comprising 11 water quality parameters collected from 13 sampling sites in Poyang Lake between 2008 and 2014, the dataset was divided into the central and northern lake groups, which corresponded to lentic and lotic regions in Poyang Lake, respectively. The spatial water quality variations and underlying patterns were investigated by performing discriminant analysis and principal component analysis (PCA). Lastly, random forests (RF) were used to predict the chlorophyll a (Chl-a) variations of the central and northern lakes. The PCA results indicated that the water quality of the central and northern areas of the lake was controlled by different environmental variables and underlying pollutant sources. The RF model outperformed the artificial neural network and linear regression and was robust with strong predictive capabilities. It was determined that the most important predictors of the Chl-a variations in the northern lake were water temperature (T) and water level, whereas transparency, T, and water level were the most efficient predictors in the central lake. The RF model can also be applied to trophic prediction in other large lakes with considerable spatial variations. This study will have implications on water quality management and eutrophication prevention in floodplain lakes with high spatial heterogeneity. 相似文献
4.
Logistic regressions, artificial neural networks, support vector machines, random forests and classification trees were used to predict habitat suitability for mayflies on basis of physical–chemical water characteristics, dominant land use type and structural parameters. As a case-study, the dataset of Flanders was used, which consisted of 4289 samples containing mayflies (presences) and 3315 samples from waters where mayflies were never encountered (absences). For all techniques, data were randomly divided in a training set (two thirds) and a test set (one third). Models were calibrated using a tenfold cross-validation on the training set and subsequently validated using the test set. All techniques delivered good models that were able to discriminate sites with and without mayflies and performance (expressed as percent correctly classified instances and kappa-statistics) was in all cases similar for the training and the test set. Artificial neural networks and random forests performed slightly better compared to the other techniques. Samples with mayflies contained significantly more oxygen, a better developed river structure, higher values for sinuosity and steeper slopes, while samples without mayflies had significantly higher values for ammonium, nitrite, Kjeldahl nitrogen, total phosphorous, orthophosphate, biological and chemical oxygen demand, pH and conductivity. Also land use differed significantly, with mayflies usually present in forests but absent in industrial areas. The prevalence of mayflies gradually increased during the nineties from about 20 to 40%, which corresponded with an improvement of the chemical water quality. During the last decade, however, water quality did not further improve and as a result, mayflies prevalence did not continue to increase. Based on the planned measures, an ensemble forecast using the five mentioned modelling techniques predicted that mayflies prevalence will increase to 46% by 2015 and to 72% by 2027. To meet the requirements of the European Water Framework Directive, which states that all surface waters should obtain a good ecological quality, extra efforts will be needed to decrease nutrient concentrations and to improve habitat quality. 相似文献
5.
This project has been developed to evaluate the possible relationship between the cesspit (pit latrine) in as far as it degrades the quality of underground water. Its importance is due to the fact that in the rural communities in the State of São Paulo (Brazil) this type of cesspit is very common as a means of sewage disposal and these communities use underground water for their supply of drinking water. Rural properties distributed over the rural area in the municipality of São José do Rio Preto were selected. A preliminary study was then set up to determine the social situation and health of the households as well as qualitative evaluations on the type of water supply and sewage disposal of these communities. Campaigns of water sampling then followed and laboratory analyses of water taken from wells were carried out. Parameters were set up to evaluate the potability according to Brazilian legislation (2004) paying attention to microbiologic (coliforms, C rytosporidium sp., and adenovirus). The analyses showed evidence of possible inter-action between the wells and the sewage effluents and drainage in these communities. A PCR reaction to detect adenovirus showed a presence in 53.3% of the samples. The tests for the detection of Cryotosporidium sp all showed a negative result. 相似文献
6.
Based on feed composition, fish composition and feed conversion, some theoretical effects of feeding on waste discharge are calculated to illustrate the appropriateness of farm effluent monitoring. The effects of feed conversion and feed spillage and feed composition on waste discharge (suspended and dissolved N, P & COD) are demonstrated. Slight variations in feed conversion at the moment of sampling, especially those evoked by feed spillage, have tremendous consequences for discharge values. It appears crucial to determine whether observed conversions are explained by inherent efficiencies of fish growth, or whether higher growth efficiencies are combined with feed spillage. Therefore, thorough knowledge of relationships between nutrient intake and growth should be applied to effluent assessment. A calculation is presented to serve as a preliminary assessment of the impacts of these variables on water quality monitoring. The concept is illustrated using measurements from a recirculation pilot eel culture system. 相似文献
7.
Coastal environments contain some of the marine world's most important ecosystems and represent significant resources for human industry and recreation. Water quality in the coastal environment is extremely important for a number of reasons from the protection of marine organisms and the well being of marine ecosystems to the health of people in the region and the safety of industries such as aquaculture. As a result it is essential that environmental health in coastal environments is monitored. Traditional monitoring methods include assessment of biological indices or direct measurements of water quality, which are based on in situ data collection and hence are often spatially or temporally limited. Remote sensing imagery is increasingly used as a rich source of spatial information, providing more detailed coverage then other methods. But the complexity of information in the imagery requires new analysis techniques that allow us to identify the components and possible causes of spatial and temporal variability.This paper presents a review of methods to analyse spatial and temporal variations in remote sensing data of coastal water quality and discusses and compares these methods and the outcomes they achieve. Selected techniques are illustrated by using a sample dataset of MODIS chlorophyll- a imagery. We consider classification methods (cluster analysis, discriminant analysis) that may be used in exploratory, confirmatory and predictive ways, methods that summarize and identify patterns within complex datasets (factor analysis, principal components analysis, self-organizing maps), and techniques that explicitly analyse spatial relationships (the semivariogram and geographically weighted regression). Each technique has a different purpose and addresses different questions. This review identifies how these methods can be utilized to address water quality variability in order to foster a wider application of such techniques for coastal water quality assessment and monitoring. 相似文献
8.
AbstractThe analysis of a sample of Archaic points from , private collections led the author to question the effectiveness of traditional tool typologies to explain morphological variability. Causes of variations are discussed; time, space and functional specialization are estimated to contribute only part of the total variation. A systems model relating point manufacture and use to hunting strategies is presented. Chipping and retouching techniques are defined as elements of the system variety. Technical choices constitute the mechanisms maintaining the system in a state of equilibrium; technological change results from the introduction of new sets of techniques. The nature of the choices and the range of variations tolerated within the system are deduced from the analysis of the sample. The analysis relies on a recently developed method of recording morphological characteristics. More extensive methods of testing the model are briefly described. 相似文献
9.
Rapid molecular testing methods are poised to replace many of the conventional, culture-based tests currently used in fields such as water quality and food science. Rapid qPCR methods have the benefit of being faster than conventional methods and provide a means to more accurately protect public health. However, many scientists and technicians in water and food quality microbiology laboratories have limited experience using these molecular tests. To ensure that practitioners can use and implement qPCR techniques successfully, we developed a week long workshop to provide hands-on training and exposure to rapid molecular methods for water quality management. This workshop trained academic professors, government employees, private industry representatives, and graduate students in rapid qPCR methods for monitoring recreational water quality. Attendees were immersed in these new methods with hands-on laboratory sessions, lectures, and one-on-one training. Upon completion, the attendees gained sufficient knowledge and practice to teach and share these new molecular techniques with colleagues at their respective laboratories. Key findings from this workshop demonstrated: 1) participants with no prior experience could be effectively trained to conduct highly repeatable qPCR analysis in one week; 2) participants with different desirable outcomes required exposure to a range of different platforms and sample processing approaches; and 3) the collaborative interaction amongst newly trained practitioners, workshop leaders, and members of the water quality community helped foster a cohesive cohort of individuals which can advocate powerful cohort for proper implementation of molecular methods. 相似文献
10.
Zoning is an important tool used in the management of protected areas and wetlands. It has been developed to apply conservation objectives at different levels of management where conflicting uses can be taking place. GIS is increasingly used to solve land allocation problem with techniques based on zoning, varying from simple overlays to complex multi-criteria evaluation techniques (MCE). This study presents a new approach to the development of zoning plans for Ramsar sites that exhibit major seasonal variations in conservation value and human use and threats. It employs a well-defined GIS-based MCE technique which involves both expert judgment and a set of criteria based on ecological and potential threats. A GIS model using the additive approach in MCE was developed to evaluate Sabkhat Al-Jabboul the only Ramsar site in Syria. The model was applied separately for the spring and winter to accommodate seasonal changes in the intensity and spatial distribution of conservation areas and threats across the site. Separate zoning plans were developed for each of the two main seasons. The zoning plan of the spring season, which is the birds breeding season, included three management zones; the special conservation zone, the conservation buffer zone, and the wise use zone. The winter zoning plan, where the bird feeding activity was the major activity includes two zones: a special conservation zone and a wise use zone. Thus, in cases like Sabkhat Al-Jabboul, where the wetlands are subject to significant seasonal variations, in their ecology and human utilization, it is recommended that flexible seasonal zoning plans are developed to assist in the organization of permitted activities, and to reduce the potential human impacts throughout the year. 相似文献
11.
Diatoms are major contributors to global carbon fixation and constitute a significant portion of biofilms found in lotic ecosystems. Despite their widespread abundance and the fact that extensive studies have been performed on morphological features of frustules, molecular tools for the identification of diatoms are not commonly available. This study focuses on the development of oligonucleotide probes for the detection of diatom species relevant to water quality assessment. The selected panel of diatoms covers all the species found in water of varying quality from the rivers of central-East Apennine (Italy). Small subunit rRNA-targeted probes were applied to a microarray platform as well as to a new technique termed Primer–Probe, with the aim of obtaining a molecular tool suitable for accurate identification of both single and mixed species diatom populations. The Primer–Probe technique together with dot-blot assays proved to be ideal for the preliminary screening of a large set of DNA oligonucleotides designed by ARB software. It was shown that microarrays, as a promising technology for rapid and simultaneous detection of a wide range of species-specific genetic markers, can be adapted to monitor changes within a diatom community. It is suggested that microarrays will provide a molecular basis for microbial identification to support standard microscopy techniques used by ecologists and environmental scientists for monitoring water quality. 相似文献
12.
A three-dimensional structure for 16 S RNA has been produced with a computer protocol that is not dependent on human intervention. This protocol improves upon traditional modeling techniques by using distance geometry to fold the molecule in an objective and reproducible fashion. The method is based on the secondary structure of RNA and treats the molecule as a set of double-stranded helices that are linked by flexible single-strands of variable length. Data derived from chemical cross-linking studies of 16 S RNA and tertiary phylogenetic relationships provide the constraints used to fold the molecule into a compact three-dimensional form. Possibly subjective evaluation of the input data are transformed into verifiable quantitative parameters. Relationships based on general locations within the 30 S subunit or on protein-RNA interactions have been specifically excluded. The resolution of the model exceeds that of electron micrographs and approaches that obtained in preliminary X-ray crystal structures. The model size of 245 x 190 x 140 A is compatible with that of the 30 S subunit as determined by electron microscopy. The volume of the model is 1.87 x 10(6) A which is similar to that of the small subunit in a preliminary X-ray crystal structure. The radius of gyration of the model structure of 76 A is intermediate to that seen for partially denatured and fully folded 16 S RNA. Computer graphics are used to display the results in a manner that maximizes the opportunities for human visual interpretation of the models. A format for displaying the structures has been developed that will make it possible for researchers who have not devoted themselves to ribosomal modeling to comprehend and make use of the information that the models embody. On this basis the computer-generated models are compared with models developed by other researchers and with structural data not included in the folding parameter data set. 相似文献
13.
Most propulsion systems of vehicles travelling in the aquatic environment are equipped with propellers. Observations of nature, however, show that the absolute majority of organisms travel through water using wave motion, paddling or using water jet power. Inspired by these observations of nature, an innovative propulsion system working in aquatic environment was developed. This paper presents the design of the water propulsion system. Particular attention was paid to the use of paddling techniques and water jet power. A group of organisms that use those mechanisms to travel through water was selected and analysed. The results of research were used in the design of a propulsion system modelled simultaneously on two methods of movement in the aquatic environment. A method for modelling a propulsion system using a combination of the two solutions and the result were described. A conceptual design and a prototype constructed based on the solution were presented. With respect to the solution developed, studies and analyses of selected parameters of the prototype were described. 相似文献
14.
Laser-assisted microdissection (LAM) permits the procurement of relatively pure cell populations from histological sections. When applied to the kidney, LAM combined with molecular biological techniques has expanded our understanding of renal biology and pathology. Both frozen and fixed renal tissues can be microdissected. However, sample type and tissue processing can influence the quality of molecular data generated. Data analysis may also be complicated by relative variations in gene expression levels. Importantly, preliminary studies have shown that molecular data obtained following LAM on the kidney can offer new diagnostic and prognostic information. Thus, LAM and molecular markers may eventually become incorporated into the routine kidney biopsy examination. 相似文献
15.
保障农业用水安全和生态安全是流域水资源管理的重点,针对黄河口和山东引黄灌区的用水矛盾,采用阈值分析与地统计学方法,考虑作物蒸散发和有效降雨计算山东省引黄灌区灌溉需水量,在优先保障黄河口不同等级生态需水条件下分析灌区(划分为不同调控区)可用水量的响应特征,以地理信息系统(GIS)为平台计算具有时空差异的山东省引黄灌区农业用水安全压力指数,进而评价多时空尺度下的山东省引黄灌区农业用水安全。结果表明,在平水年,保障适宜等级的生态需水后大概有33%的年份农业用水安全存在压力,保障最低等级的生态需水约有27%的农业用水面临短缺,但是大部分情况下农业用水安全压力指数都在30%之下,然而保障最高等级生态需水后,有50%以上的年份存在农业用水安全压力,这种压力无论是从出现频次还是在指数强度上都有明显增加。在空间尺度上,以打渔张、刘春家、麻湾和簸箕李等灌区为代表的调控区2、11、13、14和17的农业用水压力显著,代表年内保障最低等级的生态需水后调控区的农业用水安全压力指数超过了20%,保障适宜等级的生态需水后,大部分调控区的农业用水安全压力指数超过了20%,调控区2和13的压力指数超过了30%,保障最高等级的生态需水后大部分调控区的农业用水安全压力指数超过了60%。在引黄水量调配过程中,应该按照水文年的不同保障合理的生态水量,同时充分考虑水文气象因子的空间差异性,在不同调控区细化分配方案,平水年份保障适宜等级生态需水后农业用水短缺由55.28降低到18.25亿m 3。该评价方法反映了优先保障生态需水后灌区农业水资源保障情况,并能有效降低农业和生态用水之间的矛盾,为管理部门进行"精细配水"提供依据。 相似文献
16.
Simple methods for the registration of translational diffusion of water in apoplast and vacuolar and cytoplasmic symplasts were developed. The methods are based on spin-echo NMR with a pulsed magnetic field gradient and are realized by preliminary inversion of magnetization and the use of paramagnetic doping. It was shown that the diffusion of a part of root water in segments of mais roots is more enhanced than that for the bulk water. The results are explained by the appearance of the rotational movement of the protoplasm and in terms of the hypothesis of water transfer along the apoplast, which balances the cytoplasmic symplast. 相似文献
17.
Understanding the primary effects of anthropogenic activities and natural factors on river water quality is important in the study and efficient management of water resources. In this study, analysis of Variance (ANOVA), Principal component analysis (PCA), Pearson correlations, Multiple regression analysis (MRA) and Redundancy analysis (RDA) were applied as an integrated approach in a GIS environment to explore the temporal and spatial variations in river water quality and to estimate the influence of watershed land use, topography and socio-economic factors on river water quality based on 3 years of water quality monitoring data for the Cao-E River system. The statistical analysis revealed that TN, pH and temperature were generally higher in the rainy season, whereas BOD 5, DO and turbidity were higher in the dry season. Spatial variations in river water quality were related to numerous anthropogenic and natural factors. Urban land use was found to be the most important explanatory variable for BOD 5, COD Mn, TN, DN, NH 4
+-N, NO 3
−-N, DO, pH and TP. The animal husbandry output per capita was an important predictor of TP and turbidity, and the gross domestic product per capita largely determined spatial variations in EC. The remaining unexplained variance was related to other factors, such as topography. Our results suggested that pollution control of animal waste discharge in rural settlements, agricultural runoff in cropland, industrial production pollution and domestic pollution in urban and industrial areas were important within the Cao-E River basin. Moreover, the percentage of the total overall river water quality variance explained by an individual variable and/or all environmental variables (according to RDA) can assist in quantitatively identifying the primary factors that control pollution at the watershed scale. 相似文献
18.
Inland lake of Vembanad has benefited from continuous monitoring to evaluate water quality which has declined due to increased anthropogenic activities and climate change. Remote sensing techniques can be used to estimate and monitor inland water quality both spatially and temporally. An empirical model is presented in Vemaband lake that retrieves the specific water quality parameters through correlations between various spectral wavelengths of Sentinel-2MSI (S2MSI) with field-measured water quality parameters. This approach includes the combinations of various bands, band ratios, and band arithmetic computation of satellite sensors of spectral datasets. The specific inland water quality parameters such as chlorophyll-a (chl-a), total suspended solids (TSS), turbidity, and secchi disc depth (SDD) were retrieved from the developed water quality model through Sentinel-2A remote sensing reflectance. The result illustrates that Specific Inland Water Quality Parameters (SIWQP) strongly correlated with S2MSI reflection spectral wavelengths. The SIWQP models are constructed for TSS (R2?=?0.8008), Chl-a (R2?=?0.8055), Turbidity (R2?=?0.6329) and SDD (R2?=?0.7174).The spatial distribution of SIWQPs in Vembanad lake for March 2018 is mapped and shows the lake's water quality distribution. The research from Sentinel-2, MSI has potential and is appropriate in high spectral and spatial characteristics for retrieving and continuous monitoring of water quality parameters in the regional scale of inland water bodies. 相似文献
19.
The water quality of the lakes in south western Friesland is influenced by a rather complex hydrology. The purpose of the abiotic part of the eutrophication project, started in 1984 and focused on phosphorus, is to model hydrology and phosphorus dynamics, in order to compare scenarios for policy and management.A brief survey is given of the preliminary results of the abiotic studies: hydrology, water quality, external loading from surrounding polders, sedimentary phosphorus and internal loading. The two largest lakes, Tjeukemeer and Slotermeer, are compared regarding these processes. 相似文献
20.
A simple, non-destructive procedure is described to determine the quality of DNA arrays before they are used. It consists of a preliminary staining step of the DNA microarray by using SYBR green II, a fluorophore with specific affinity for ssDNA, followed by a laser scan analysis. The surface quality, integrity and homogeneity of each DNA spot of the array can thus be assessed. After this preliminary control, which may avoid further analytical steps that lead to the waste of precious biological samples, a fully reversible staining procedure is performed that produces an array ready for subsequent use. 相似文献
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