Ecological Water Quality Research Articles

Studi Kesesuaian Pantai Jemeluk Sebagai Kawasan Wisata Bahari Kabupaten Karangasem, Provinsi Bali

Jemeluk Beach is located in Purwakerti village, district of Abang, Karangasem regency. Jemeluk Beach is a developing tourism sector in Karangasem, which has the potential for coral reefs and various types of reef fish. Jemeluk Beach has snorkeling and diving tourism activities to develop its potential. With this is potential, s necessary to conduct research to analyze and develop suitable snorkeling and diving tours in the waters of Jemeluk Beach. This research was conducted at Jemeluk Beach, there are 6 stations in the research sampling. Collecting coral reef data using the Underwater Photo Transect method. Determination the level of the suitability of the area as a diving and snorkeling tourism spot using a matrix of area suitability analysis that considered the parameters of ecological conditions and water quality conditions using three parameters. The result showed that coral reef cover value ranged from 35,78% - 81,0%, the types of lifeform found ranged from 8 - 10 species, the water transparency value ranged from 57,78 - 82,22%, the water depth at stations 1, 2 and 3 is 3 - 4 m, station 4 is 10 - 15 m, and stations 5 and 6 are 5 - 10 m, current speed ranged from 11-15 cm/s, and the tourism suitability index (IKW) for the snorkeling and diving category at Jemeluk beach is included in the S2 category, which is conditional.

Numerical Modelling of a Dam-Regulated River Network for Balancing Water Supply and Ecological Flow Downstream

Dam operation is regarded as an effective way to increase water, food, and energy security for society. However, with the increasing water demand and frequent extreme droughts, numerous rivers worldwide go through periods of water scarcity and water ecosystem deterioration to varying degrees. Balancing the water supply and ecological flow of the dam-regulated river network is essential in the context of river restoration. In this study, we proposed a hydrodynamic and water quality model of a dam-regulated river network balancing water supply and ecological flow using the Environmental Fluid Dynamics Code (EFDC). A section of Jinjiang watershed located in the southwestern of China was chosen as the study area. Firstly, the model was calibrated and validated. By comparing the simulated values with the measured values, the statistical analysis results showed that the relative root mean-squared error (RRMSE) values of water level, COD and NH3-N were 5.5–8.1%, 23.6% and 28.4%, respectively, indicating an adequate degree of agreement between simulation and observation. Based on the established model, dam operation schemes under a dry hydrologic scenario and emergency contamination scenario were formulated to ensure the requirement of ecological water flow and water quality simultaneously. For the dry hydrologic scenario, the ecological water requirement could be satisfied through the dam operation. However, in an emergency contamination scenario, regional water quality requirements cannot be met through dam operation. The dam operation only plays a role in controlling the scope of pollution. This study is expected to provide scientific support for dam-regulated river network management and downstream river ecosystem protection.

Seasonal Variation of the Ecological Water Quality in a Drinking Water Supply Dam Lake in Bongouanou (Côte d’Ivoire)

The Ichthyological Index of Wetlands (IIW), for the monitoring of the water quality of Ehuikro Lake in Bongouanou, was established. Monthly, experimental gillnet fisheries were conducted between July 2017 and June 2018 in Lake Ehuikro (Bongouanou, Ivory Coast). The fish collected were identified and counted each month, as well as the physicochemical parameters measured in-situ. A partial canonical correspondence analysis (pCCA) was used to order fish species along the axes according to physicochemical parameters to explain anthropogenic disturbances. It appears from this analysis that the water of Lake Ehuikro is of "good quality" during the rainy season and of "poor quality" during the dry season.

Ecological water quality of the Three Gorges Reservoir and its relationship with land covers in the reservoir area: implications for reservoir management

In this study, we evaluated the ecological water quality of the entire Three Gorges Reservoir (TGR) and further examined the relationship with changes in watershed land covers. Using the phytoplankton functional group-based Q index, we found that the ecological water quality in the mainstream (previously known as the Yangtze River) of TGR is good, with 84% of sites in the status above good. While the poor ecological water quality was generally observed in the backwater regions of TGR’s tributaries, with 79% of sites below the good status. Further investigating the potential impacts of the changes in land covers within the watershed on the tributary ecological water quality, we found that the percentage of urban and farmland areas had a significant (p < 0.05) negative correlation with the Q index-based ecological water quality of the tributary bays, and the forest cover had a marginally significant (p = 0.058) positive correlation with the ecological water quality. As a comparison, total nitrogen and total phosphorus in the tributary backwater regions of TGR had no reasonable correlation with the land covers within the watershed. Our study highlights that watershed management can enhance the ecological water quality in the backwater regions of TGR’s tributaries, but it likely to be a long-term process. This implies considerations of other rapid measures, such as the water level regulation approach, should also be considered in reservoir management. Our study underscores the importance of ecological water quality assessment in reservoir management and provides insights into the impacts of changes in watershed land covers on ecological water quality in backwater regions of TGR’s tributaries.

Recirculating Water through Concrete Aggregates Rapidly Produced Ecologically Hazardous Water Quality

The use of recycled concrete aggregates as a construction material is growing and this study was conducted to investigate the potential water quality issues that arise when concrete aggregates are exposed to water. The water used in the study was from a high-conservation-value wetland. It was dilute (17.8 µS cm−1), acidic (pH 5.97) and poorly buffered. The ionic composition comprised sodium, bicarbonate and chloride ions. Water was recirculated for 60 min through a control treatment and three treatments containing recycled concrete aggregates (RCAs) of different fragment sizes (10 mm, 20 mm and 60 mm). The fragment size influenced the final water quality, but the response patterns varied between the attributes tested. Post-recirculation, the RCA treatments increased the electrical conductivity by 6 to 12 times; pH by 2.3 to 3.8 pH units; and concentrations of calcium, potassium, bicarbonate and sulphate. The water exposed to RCA materials also increased the concentrations of several metals (aluminium, arsenic, copper, lead and zinc), resulting in hazardous concentrations for aquatic species according to ecological water quality guidelines. Strontium concentrations in water exposed to RCAs increased by 30 to 120 times background levels. The results from this study added further support to a growing body of evidence that the exposure of concrete materials to water can produce environmentally hazardous water quality.

Regime shifts in shallow lakes explained by critical turbidity

Worldwide, water quality managers target a clear, macrophyte-dominated state over a turbid, phytoplankton-dominated state in shallow lakes. The competition mechanisms underlying these ecological states were explored in the 1990s, but the concept of critical turbidity seems neglected in contemporary water quality models. In particular, a simple mechanistic model of alternative stable states in shallow lakes accounting for resource competition mechanisms and critical turbidity is lacking. To this end, we combined Scheffer's theory on critical turbidity with insights from nutrient and light competition theory founded by Tilman, Huisman and Weissing. This resulted in a novel graphical and mathematical model, GPLake-M, that is relatively simple and mechanistically understandable and yet captures the essential mechanisms leading to alternative stable states in shallow lakes. The process-based PCLake model was used to parameterize the model parameters and to test GPLake-M using a pattern-oriented strategy. GPLake-M's application range and position in the model spectrum are discussed. We believe that our results support the fundamental understanding of regime shifts in shallow lakes and provide a starting point for further mechanistic and management-focused explorations and model development. Furthermore, the concept of critical turbidity and the relation between light-limited submerged macrophytes and nutrient-limited phytoplankton might provide a new focus for empirical aquatic ecological research and water quality monitoring programs.

Vision meets algae: A novel way for microalgae recognization and health monitor

Marine microalgae are widespread in the ocean and play a crucial role in the ecosystem. Automatic identification and location of marine microalgae in microscopy images would help establish marine ecological environment monitoring and water quality evaluation system. We proposed a new dataset for the detection of marine microalgae and a range of detection methods, the dataset including images of different genus of algae and the same genus in different states. We set the number of unbalanced classes in the data set and added images of mixed water samples in the test set to simulate the actual situation in the field. Then we trained, validated and tested the, TOOD, YOLOv5, YOLOv8 and variants of RCNN algorithms on this dataset. The results showed both one-stage and two-stage object detection models can achieve high mean average precision, which proves the ability of computer vision in multi-object detection of microalgae, and provides basic data and models for real-time detection of microalgal cells.

ECOLOGICAL WATER QUALITY

Water quality – is a description of water’s chemical and biological composition and physical properties, which characterize it as an abiotic component of aquatic ecosystem and determine its suitability for specific consumption purposes.
 Ecological water quality (environmental water quality) – refers to the ecological well-being of an aquatic ecosystem, with the main focus on protection of the aquatic environment and human life and health. It comprises a complex of physical, chemical, biological and other parameters reflecting specific features of abiotic and biotic components of aquatic ecosystems.
 The requirements for physical, chemical and biological properties of water are set in the water quality standards, which may be developed by particular countries or introduced by international organizations.
 Ecological water quality depends upon natural and human factors. Natural factors are in their turn divided into abiotic (for example, geological, meteorological, hydrological) and biotic (for example, the ratio of primary production and organic matter destruction). The main human factors affecting water quality include artificial modification of aquatic ecosystems’ hydrological conditions and their pollution with diverse chemical compounds.
 There are a lot of approaches to ecological water quality assessment according to both abiotic (physical and chemical) and biological parameters. Physical and chemical methods take into account such parameters as water transparency, suspended particulate matter concentration (turbidity), ion composition, water hardness, total dissolved salts content, nutrients and organic matter content, dissolved gases concentration, pH. Biological methods are based upon assessing the living organisms’ (biological indicators’) response to mineral and organic substances, present in water. Various living organisms can be used as biological indicators: algae, in particular – diatoms, higher aquatic plants, different species of aquatic invertebrates and fishes. While physical and chemical methods characterize water quality at the moment of sampling, biological methods provide an integral picture of water quality for a certain time period. Besides, biological methods are more informative, because they reflect the aquatic ecosystem’s response to pollution.
 On the whole, the most reliable data on ecological water quality can be obtained by combining physical, chemical and biological methods.

Current scenario, services, concerns, and restoration perspectives of ponds in India

<p>Ponds are self-sustaining and self-regulating ecosystems that are a vital part of the hydrological cycle and play a variety of roles in the biosphere. Ponds are diverse, extremely dynamic, and highly productive as they offer various services like harbor biodiversity, tool for combating water scarcity, have roles in pollution mitigation and carbon sequestration. Ponds also offer sustainable solutions to support climate change amelioration and aquatic resource management. However, ponds are the most neglected aquatic ecosystems, despite their huge ecological functions. Thus, ponds are debasing at an alarming rate as a result of increased anthropogenic activities and anthropogenically driven changes in natural processes, wreaking havoc on ecological health and water quality. In this context, the major threats to ponds include the dumping of solid waste, increased urbanization, pollution, encroachment and climate change which have resulted in the deterioration of ponds over the years. Sustainable management and restoration of ponds are crucial as this ecosystem offers a wide array of ecological functions. As a result, this research aims to assess the current state of ponds in India in terms of monitoring, ecological services provided, and the various threats to which they are subjected. Further, the discussions on management and perspective restoration strategies of this substantial ecosystem are also included. Thereby, this study suggests better conservation strategies for restoration, reclamation, and sustainable utilization of ponds.</p>

ЗОНА ТЕМПЕРАТУРНОГО ОПТИМУМА ЦИАНОБАКТЕРИЙ В КУЙБЫШЕВСКОМ ВОДОХРАНИЛИЩЕ

Based on the results of hydrometeorological observations in the period 2016-2021, the parameters of the optimum temperature zone (TTO) for the process of mass development of cyanobacteria in the Kuibyshev reservoir were determined. Such parameters of the optimum zone as duration, intensity, upper and lower boundaries depend on the hydrometeorological conditions of a particular year. For the period 2016-2021, the average duration of the OST was 44 days, the longest - 72 days and was observed in 2021, and the shortest - 11 days and was observed in 2019. The highest intensity of OST was observed in 2021, when 10 days were characterized by low intensity, 15 days by moderate intensity, 23 days by strong intensity, 24 days by very strong intensity and 7 days by extreme intensity. The lowest intensity was observed in 2019, when 10 days were characterized by low intensity and 1 day by high intensity. The upper border of the WTO in 2021 was observed on June 21, and the lower border on September 1. In 2019, the upper limit was observed on June 23, and the lower limit on July 26. For the process of mass development of cyanobacteria, the most favorable year is 2021, and the unfavorable year is 2019. It was found that with the increase in air and water temperature, the duration and degree of intensity of the temperature optimum zone increased. Consequently, with a further increase in air temperature due to global warming, the duration and intensity of the optimum temperature zone will only increase, which will activate the process of mass development of cyanobacteria, which will negatively affect the ecological state and water quality of the Kuibyshev reservoir.

基于水量与水质的太湖流域水生态服务供需关系及多情景评估

PDF HTML阅读 XML下载 导出引用 引用提醒 基于水量与水质的太湖流域水生态服务供需关系及多情景评估 DOI: 10.5846/stxb202112223632 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41971230）；中国科学院"美丽中国生态文明建设科技工程"专项（XDA23020201）；国家自然科学基金青年项目（41701211） Supply and demand relationship and multi-scenario assessment of water ecological services related water quantity and quality in Taihu Lake Basin Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要: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。 Abstract:It is essential to conduct supply and demand assessment of water ecological services across multiple spatial scales by integrating water quantity and quality for identifying water shortage issues caused by water pollution in humid regions. This study developed a comprehensive model that integrated water quantity and quality for quantifying the supply-demand relationships of water ecological services for the Taihu Lake Basin (TLB). This study also constructed three optimized scenarios (Water Efficiency Improvement, Fertilization Reduction, and Land Use Structure Optimization) to explore the spatial variations and key driving factors of water resources supply and demand on the grid, sub-basin, and county levels. We got the following conclusions:(1) The TLB was sufficient in water quantity, but it was deficient in water quality. Water efficiency improvement significantly reduced the demand for water resources in the TLB. Fertilization reduction and land use optimization greatly improved water quality. (2) The supply and demand assessment of water ecological services across the three spatial scales could help in identifying key areas for promoting sustainable water use in the TLB. (3) Urban land was primarily located in the regions with deficient water quantity. In comparison, croplands dominated the regions with deficient water quality, while these regions of deficient water quality were also comprised of large areas of urban land when assessed at the county level. (4) Land use optimization such as grain for green and riparian conservation was the most effective in improving water quality for the TLB, but it was at the huge cost of cropland losses. Therefore, coupling other optimization ways such as water efficiency improvement that would be the best measurement for solving pollution-caused water shortage issues in the TLB. 参考文献 相似文献 引证文献

ВЛИЯНИЕ МАССОВОГО РАЗВИТИЯ ЦИАНОБАКТЕРИЙ НА ФОРМИРОВАНИЕ КАЧЕСТВА ВОДЫ КУЙБЫШЕВСКОГО ВОДОХРАНИЛИЩА (ПРОБЛЕМА И ПУТИ РЕШЕНИЯ)

The process of mass development of cyanobacteria has a negative impact on the ecological state and water quality of the reservoirs of the Volga-Kama cascade, which are used for drinking water supply, fisheries and recreation. The main goal of the research is to assess the impact of the mass development of cyanobacteria on the formation of water quality using the example of the Kuibyshev reservoir in the context of global warming. Comprehensive observations were carried out in the period 2001-2021. on the largest in Europe Kuibyshev reservoir with seasonal, weekly and daily regime of water line regulation. The research results show that during the period of "water bloom" organic water pollution increases. So permanganate oxidation in summer exceeds the permissible value by 1.5-2.0 times, which creates problems in providing the population with high-quality drinking water. The mass development of cyanobacteria disrupts the oxygen regime of the reservoir. The seasonal variability of the dissolved oxygen concentration includes four periods, which differ in the different directions of the processes of formation of the oxygen regime. Within the year, two minima of the dissolved oxygen content are observed: winter and summer. In the summer minimum, the concentration of dissolved oxygen decreases to critical values, and is 4-5 mg/dm3. The mass development of cyanobacteria has a significant influence on the formation of the summer oxygen minimum. As a result of photosynthetic aeration, a thin surface layer of water supersaturated with oxygen is formed, which disrupts the process of oxygen absorption from the atmosphere in a significant part of the reservoir water area. Under conditions of growing nutrient load and global climate warming, the intensity and scale of the process of mass development of cyanobacteria in the Kuibyshev reservoir will only increase, which will lead to a further increase in oxygen deficiency, deterioration of water quality and the emergence of water use risks.

Land use and environmental quality in Ireland over two decades of contrasting agricultural trends

Global awareness and scrutiny of food production systems, including competition for land between agriculture and nature-based solutions to climate change, has increased immensely recently. In Ireland, around 70% of land area is used for agriculture, mostly pasture-based livestock production. Cattle numbers began to decline in the late 1990s, as milk productivity per cow increased along with the European Union policy of intensification implemented in 1998. Phasing out of the EU milk quota system from 2011 onwards initiated an increase in dairy cow numbers, which rose by 46% by 2020. This development has reversed environmental progress. This study outlines the impact of contrasting policies that have contributed to abatement and intensification of greenhouse gas and ammonia emissions from Ireland’s agriculture, forestry and other land use (AFOLU) sector, along with impacts on water quality effects. Ireland achieved most environmental targets during the 2000s. However, between 2010 and 2019, agricultural greenhouse gas emissions increased by 12% and annual ammonia emission ceilings exceeded the national limit in seven of those years. Around 6% of rivers lost their good or high ecological water quality status. These developments jeopardise compliance with contemporary environmental targets, such as achieving a 25% reduction in greenhouse gas emissions from agriculture by 2030, and AFOLU climate neutrality by 2050. Achieving environmental quality targets will necessitate far-reaching and immediate development of policy for the land use sector beyond the implementation of currently proposed mitigation measures.

Machine Learning for Water Quality Assessment Based on Macrophyte Presence

The ecological state of the Danube River, as the world’s most international river basin, will always be the focus of scientists in the field of ecology and environmental engineering. The concentration of orthophosphate anions in the river is one of the main indicators of the ecological state, i.e., water quality and level of eutrophication. The sedentary nature and ability to survive in river sections, combined with the presence of high levels of orthophosphate anions, make macrophytes an appropriate biological parameter for in situ prediction of in-river monitoring processes. However, a preliminary literature review identified a lack of comprehensive analysis that can enable the prediction of the ecological state of rivers using biological parameters as the input to machine learning (ML) techniques. This work focuses on comparing eight state-of-the-art ML classification models developed for this task. The data were collected at 68 sampling sites on both river sides. The predictive models use macrophyte presence scores as input variables, and classes of the ecological state of the Danube River based on orthophosphate anions, converted into a binary scale, as outputs. The results of the predictive model comparisons show that support vector machines and tree-based models provided the best prediction capabilities. They are also a low-cost and sustainable solution to assess the ecological state of the rivers.

Assessment of Remote Sensing Ecological Quality by Introducing Water and Air Quality Indicators: A Case Study of Wuhan, China

In the context of ecological protection and urban expansion, the quality of the ecological environment and ecological security are gravely at risk. A simple, effective, and comprehensive assessment method for regional environmental quality monitoring is urgently required at this time. This study proposes a comprehensive approach for evaluating regional ecological quality. Based on Landsat TM+OLI/TIRS images, indicators representing the ecological quality of land and water were constructed. Land ecological quality consists of land surface moisture (WET), normalized difference vegetation index (NDVI), normalized building bare soil index (NDBSI), and land surface temperature (LST), which represent humidity, greenness, dryness, and temperature, respectively. At the same time, the remote sensing indices of chlorophyll_a (chl_a) and suspended solids (SS) were constructed to characterize the water quality. Air quality was characterized based on aerosol optical depth (AOD) in MCD19A2. By introducing water and air quality indicators and utilizing principal component analysis, a remote sensing ecological index that improves water area assessment (WIRSEI) was established and applied to Wuhan from 2000 to 2020. The driving force of WIRSEI change was analyzed using the geographically weighted regression (GWR) model. The results revealed that (1) air quality AOD and humidity WET greatly impacted the ecological quality (WIRSEI). WIRSEIs in seven central urban areas were significantly lower than that in six remote urban regions, and the ecological quality of lakes was higher than that of rivers. (2) From 2000 to 2020, Wuhan’s overall WIRSEI showed a “rising–falling–rising–stable” trend. In most regions, the degree of ecological quality change was relatively small; most grades were “no change”, “slightly better”, and “slightly worse”, representing 88–93% of the total area. (3) The change in WIRSEI from 2000 to 2020 was closely related to urban expansion, population change, and economic development. The effects of land use and socioeconomic changes on WIRSEI were significantly different in spatial distribution. Compared to the driving factors, land use dynamics (LUCD) significantly impacted WIRSEI changes, while the effects of gross domestic product (GDP) and population (POP) were very small. This study uses WIRSEI to evaluate the regional ecological quality, providing a vital reference and basis for enhancing regional ecological quality assessment methods, promoting ecological environmental protection and restoration, regional coordination, and sustainable development. The research results show that the proposed approach is simple and effective, strongly supporting regional ecological quality and protection monitoring.

Machine learning model ensemble based on multi-scale predictors confirms ecological segregation and accurately predicts the occurrence of net-spinning caddisfly larvae species groups (Trichoptera: Hydropsychidae) at catchment-scale

In riverine ecosystems the species distribution, determined primarily by their environment often shows zonation patterns that are also typical in the case of net-spinning caddisfly larvae (Trichoptera: Hydropsychidae). In the present research, we aimed to build an ensemble of base learner machine learning (ML) models based on the most important environmental parameters shaping the sequential distribution of ten Central European species of the genus Hydropsyche in the North Hungarian catchment area of Tisza, one of the major rivers of Central and Eastern Europe. The model could explain and effectively predict the occurrence of species and/or groups of them with similar niche preferences. Variable selection revealed the importance of predictors, measured at various spatial scales and with gradient-like characteristics, such as elevation, annual means of discharge, water temperature or the composition of habitat substrates as well as those related to the ecological quality of water or anthropogenic impacts, like annual means of dissolved oxygen and orthophosphate-phosphorous content. Trained on the predictions of different base learner models a final ensemble model predicted the presence and absence of three individual species and three species-groups with significantly improved overall accuracy. High group-wise balanced accuracies of the final model shows that longitudinal, catchment-scale distribution models in stream ecosystems are best built on predictors with variable spatial scales, several of which are routinely measured or recorded in environmental monitoring programmes. Accurate species distribution models (SDMs), capable of adequately predicting presence and absence of bio-indicator taxa, such as Hydropsyche species, can be applied to support environmental management or conservation measures regarding streams and rivers, that are among the most vulnerable of anthropogenic pollution, hydrologic alteration, climate change and biodiversity loss.

Comparative environmental RNA and DNA metabarcoding analysis of river algae and arthropods for ecological surveys and water quality assessment

Environmental DNA (eDNA) metabarcoding is widely used for species analysis, while the use of environmental RNA (eRNA) metabarcoding is more limited. We conducted comparative eDNA/eRNA metabarcoding of the algae and arthropods (aquatic insects) in water samples from Naka River, Japan, to evaluate their potential for biological monitoring and water quality assessment. Both methods detected various algae and arthropod species; however, their compositions were remarkably different from those in traditional field surveys (TFSs), indicating low sensitivity. For algae, the species composition derived from eDNA and eRNA metabarcoding was equivalent. While TFSs focus on attached algae, metabarcoding analysis theoretically detects both planktonic and attached algae. A recently expanded genomic database for aquatic insects significantly contributed to the sensitivity and positive predictivity for arthropods. While the sensitivity of eRNA was lower than that of eDNA, the positive predictivity of eRNA was higher. The eRNA of terrestrial arthropods indicated extremely high or low read numbers when compared with eDNA, suggesting that eRNA could be an effective indicator of false positives. Arthropod and algae eDNA/eRNA metabarcoding analysis enabled water quality estimates from TFSs. The eRNA of algae and arthropods could thus be used to evaluate biodiversity and water quality and provide insights from ecological surveys.

Adapting classical water quality diagrams for ecohydrological and policy applications

Ecological values of water have gained increasing attention over the past decades in both (eco)hydrological research and water resources management. Water quality is an important ecological steering variable, and graphical water quality diagrams may aid in rapid interpretation of the hydrochemical status of a site. Traditionally used water quality diagrams for showing multiple variables (e.g. Stiff, Maucha) were developed primarily for hydrogeological purposes, with limited information on ecologically relevant nutrient parameters.This paper presents adapted classical water quality diagrams that retain the traditional information on ions for hydrogeological characterization, and additionally provide information on nutrients for ecological water quality characterization.A scaling factor is used for the minor ions to visually get them across more equally compared to the macro-ion ions in the water quality diagram. Scaling of minor ions is presented based on average concentrations, as well as on water quality policy norms. Four different water quality diagrams are presented, all with the same ions included, but with different appearances to suit different preferences of individual users. Regional, national and continental scale data are used to illustrate how the different diagrams show spatial and temporal water quality characteristics.The adapted diagrams are innovative with respect to adding comprehensive visual information on the four ecohydrologically relevant nutrient species levels (NO3, NH4, PO4, K), advanced insight in redox status from the combination of four redox sensitive parameters (Fe, NO3, SO4, NH4) and the option to scale minor ions relative to average measured concentrations or to water quality policy norms. Using policy norms for scaling has the advantage of providing an ‘alarm function’ of exceedance of norms when concentrations surpass the ring used in the diagram. We discuss possible standardisation of scaling factors to enable comparability between sites.

Effects of Submerged Macrophyte Decomposition on Water Quality

Submerged macrophytes play an important role in aquatic ecosystems and are widely used in aquatic ecological restoration. However, when submerged macrophytes fade, litter, or even decompose, they may cause adverse effects on water quality. In this article, indoor experiments were carried out to study the quantitative influence of submerged plant decomposition on water quality. Six submerged macrophytes commonly used in aquatic ecological restoration in Sichuan Province, including Elodea canadensis Michx., Potamogeton wrightii Morong, Potamogeton crispus L., Vallisneria spinulosa, Ceratophyllum demersum L., and Potamogeton pectinatus L., were selected to measure the change processes of nutrients during macrophyte decomposition at 10°C, 20°C and 30°C. The results showed that the decomposition of submerged plants released nutrients into the water body, causing water pollution. At 10°C, the total phosphorus (TP) concentration of water bodies containing submerged plant litter increased by 1.97 to 5.97 times on the 50th day compared to the 5th day, while the TP concentration of the blank control group without hydrophytes decreased from 0.39 mg.L-1 to 0.22 mg.L-1 due to self-purification. The ammonia nitrogen (NH3-N) concentration increased by 3.82-9.58 times on the 50th day compared with the 5th day, while the value in the blank control group decreased from 1.42 mg.L-1 to 0.78 mg.L-1. This result indicated that the water body had a certain self-purification ability, but the decomposition of aquatic macrophytes had a negative impact on this progress. Increasing temperatures could accelerate plant decay processes. Initially, the concentrations of NH3-N and TP were high with high temperatures. After 45 days of reaction, the NH3-N and TP concentration in the water bodies appeared to be 30°C<20°C<10°C, indicating that decomposition was further advanced when the temperature was higher. This study provides a theoretical basis for water ecological management and water quality protection.

Determination of the ecological water quality in the Orienco stream using benthic macroinvertebrates in the Northern Ecuadorian Amazon.

In recent years, pollution of watercourses in nearby protected ecosystems has increased due to urbanization. Standard physiochemical methods and probes are one way to monitor watercourses for quality. However, they often do not provide the full ecological status of the body of water. In this work, we set out to assess the ecological water quality of an urban stream by using benthic macroinvertebrates as bioindicators. We conducted the work on the Orienco stream in Lago Agrio in the province of Sucumbíos in the Northern Ecuadorian Amazon (NEA). The stream has become a sink of raw domestic sanitary wastewater from rural and urban areas. A total of 4511 macroinvertebrates from 10 families were identified across 17 sampling points. We compared our results from the biotic indices derived from the macroinvertebrates to standard water-quality parameters (temperature, conductivity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total suspended solids, ammonia-nitrogen, and pH) simultaneously sampled in the stream. The standard parameter results indicated that the water-quality levels of the stream met the Ecuadorian water-quality criteria most of the time. However, the results from the biotic indices classified the stream water as poor or very poor water quality. The results from the Biological Monitoring Working Party, Average Score per Taxon, and Family Biotic Indices had overall scores of heavily polluted waters of 45, 4.5, and 8.74, respectively. Furthermore, these results were consistent with reduced richness and evenness, and overall lower Shannon diversity and relatively higher Simpson Dominance indices of 0.71 and 2.56, respectively. We conclude that the macroinvertebrates were better indicators of the ecological water quality of the Orienco stream than the water-quality parameters from standard methods and probes alone. Our findings highlight the need for more integrated ecological assessments, which can provide critical information to the management and conservation strategies of urban watercourses in the NEA region. Integr Environ Assess Manag 2023;19:615-625. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).