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Phytoplankton constitutes a diverse array of short-lived organisms which derive their nutrients from the water column of lakes. These features make this community the most direct and earliest indicator of the impacts of changing nutrient conditions on lake ecosystems. It also makes them particularly suitable for measuring the success of restoration measures following reductions in nutrient loads. This paper integrates a large volume of work on a number of measures, or metrics, developed for using phytoplankton to assess the ecological status of European lakes, as required for the Water Framework Directive. It assesses the indicator strength of these metrics, specifically in relation to representing the impacts of eutrophication. It also examines how these measures vary naturally at different locations within a lake, as well as between lakes, and how much variability is associated with different replicate samples, different months within a year and between years. On the basis of this analysis, three of the strongest metrics (chlorophyll- a, phytoplankton trophic index (PTI), and cyanobacterial biovolume) are recommended for use as robust measures for assessing the ecological quality of lakes in relation to nutrient-enrichment pressures and a minimum recommended sampling frequency is provided for these three metrics. [ABSTRACT FROM AUTHOR]

The emergence of metacommunity theory has provided a framework for studying the spatial structure of biological communities. To unravel the underlying driving mechanisms of macroinvertebrate metacommunity structure and diversity, this paper evaluates macroinvertebrate data from a water body in eastern China using variance decomposition and stratified partitioning. The results suggest that spatial processes dominate macroinvertebrate metacommunity structure, while the combined effects of spatial processes, aquatic environment, and geoclimatic factors also explain part of the macroinvertebrate community structure. Spatial processes, aquatic environment, and geoclimatic factors significantly influenced macroinvertebrate alpha diversity and indirectly influenced beta diversity through alpha diversity. Therefore, the significant effects of spatial processes and geoclimatic variables cannot be ignored in biological assessments, especially biodiversity assessments. Our findings elucidate the metacommunity dynamics in the region and provide crucial information for conservation planning in riverine ecosystems. [ABSTRACT FROM AUTHOR]

The emergence of metacommunity theory has provided a framework for studying the spatial structure of biological communities. To unravel the underlying driving mechanisms of macroinvertebrate metacommunity structure and diversity, this paper evaluates macroinvertebrate data from a water body in eastern China using variance decomposition and stratified partitioning. The results suggest that spatial processes dominate macroinvertebrate metacommunity structure, while the combined effects of spatial processes, aquatic environment, and geoclimatic factors also explain part of the macroinvertebrate community structure. Spatial processes, aquatic environment, and geoclimatic factors significantly influenced macroinvertebrate alpha diversity and indirectly influenced beta diversity through alpha diversity. Therefore, the significant effects of spatial processes and geoclimatic variables cannot be ignored in biological assessments, especially biodiversity assessments. Our findings elucidate the metacommunity dynamics in the region and provide crucial information for conservation planning in riverine ecosystems. [ABSTRACT FROM AUTHOR]

Eastern Continental shallow lakes are specific with their higher nutrient concentration compared to other lentic water bodies with similar specifications. Nonetheless, their phytoplankton and macrophyte assessment systems used more often than others within state monitoring programs, are weakly influenced by nutrient concentrations, unlike all other lake types in Europe. In this study, we used all available data for Eastern Continental shallow lakes on the Black Sea coast of Bulgaria from the state monitoring for 14 years (2008-2021). The goal was to find how environmental variables influence the ecological status assessment by phytoplankton and macrophyte-related indices. Likewise, it was important to understand the studied parameter's interrelations within Dourankoulak Lake and the lake complex Shabla-Ezerets. The most important environmental parameters were determined with principal component analysis since it helps find the hidden relationships. Afterwards, those variables were used for univariate linear regression testing because of its simplicity and reliability. The aim was to find the best-suited parameters for the ecological status explanation by different biological indices, which can be used for further predictions of the ecosystem condition. In addition, nitrogen--phosphorus dependency, where possible was investigated, confirming conclusions from mesocosms studies from water bodies with similar characteristics. The algae group index or the so-called "Catalán Index", in its original form of representing results and considering its ecological quality ratio values, was influenced by conductivity concentrations the most in Ezeretsko Lake and weaker at Dourankoulak Lake. Nutrient relationship with biological quality elements was not found, confirming results on a European level. In Shablensko Lake a dose-dependent relation between nitrates and phosphates was found, which shows that augmenting the quantity of nitrogen is related to the increasing concentration of phosphates. [ABSTRACT FROM AUTHOR]

Effective monitoring and management of inland waterbodies depend on reliable assessments of water quality through remote sensing technologies. Match-up analysis plays a significant role in investigating the comparability between in situ and remote sensing data of physical and biogeochemical variables. By exploring different spatial aggregations and temporal windows, we aimed to identify which configurations are most effective and which are less effective for the assessment of remotely sensed water quality data within the context of governmental monitoring programs. Therefore, in this study, remote sensing data products, including the variables of Secchi depth, chlorophyll-a, and turbidity, derived from the Copernicus satellites Sentinel-2 and Sentinel-3, were compared with in situ laboratory data from >100 waterbodies (lakes and reservoirs) in Germany, covering a period of 5 years (2016–2020). Processing was carried out using two different processing schemes, CyanoAlert from Brockmann Consult GmbH and eoapp AQUA from EOMAP GmbH & Co. KG, in order to analyze the influence of different processors on the results. To investigate appropriate spatial aggregations and time windows for validation (the match-up approach), we performed a statistical comparison of different spatial aggregations (1 pixel; 3 × 3, 5 × 5, and 15 × 15 macropixels; and averaging over the whole waterbody) and time windows (same day, ±1 day, and ±5 days). The results show that waterbody-wide values achieved similar accuracies and biases compared with the macropixel variants, despite the large differences in spatial aggregation and spatial variability. An expansion of the temporal window to up to ±5 days did not impair the agreement between the in situ and remote sensing data for most target variables and sensor–processor combinations, while resulting in a marked rise in the number of matches. [ABSTRACT FROM AUTHOR]

Changes and disturbances to water diversity and quality are complex and multi-scale in space and time. Although in situ methods provide detailed point information on the condition of water bodies, they are of limited use for making area-based monitoring over time, as aquatic ecosystems are extremely dynamic. Remote sensing (RS) provides methods and data for the cost-effective, comprehensive, continuous and standardised monitoring of characteristics and changes in characteristics of water diversity and water quality from local and regional scales to the scale of entire continents. In order to apply and better understand RS techniques and their derived spectral indicators in monitoring water diversity and quality, this study defines five characteristics of water diversity and quality that can be monitored using RS. These are the diversity of water traits, the diversity of water genesis, the structural diversity of water, the taxonomic diversity of water and the functional diversity of water. It is essential to record the diversity of water traits to derive the other four characteristics of water diversity from RS. Furthermore, traits are the only and most important interface between in situ and RS monitoring approaches. The monitoring of these five characteristics of water diversity and water quality using RS technologies is presented in detail and discussed using numerous examples. Finally, current and future developments are presented to advance monitoring using RS and the trait approach in modelling, prediction and assessment as a basis for successful monitoring and management strategies. [ABSTRACT FROM AUTHOR]

Microcystin-LR (MC-LR) is a secondary metabolite produced by cyanobacteria, globally renowned for its potent hepatotoxicity. However, an increasing body of research suggests that it also exhibits pronounced neurotoxicity. PP2A is a fundamental intracellular phosphatase that plays a pivotal role in cell development and survival. Although extensive research has focused on the binding of MC-LR to the C subunit of PP2A, few studies have explored the key amino acid sites that can prevent the binding of MC-LR to PP2A-C. Due to the advantages of Caenorhabditis elegans (C. elegans), such as ease of genetic editing and a short lifespan, we exposed nematodes to MC-LR in a manner that simulated natural exposure conditions based on MC-LR concentrations in natural water bodies (immersion exposure). Our findings demonstrate that MC-LR exerts comprehensive toxicity on nematodes, including reducing lifespan, impairing reproductive capabilities, and diminishing sensory functions. Notably, and for the first time, we observed that MC-LR neurotoxic effects can persist up to the F3 generation, highlighting the significant threat that MC-LR poses to biological populations in natural environments. Furthermore, we identified two amino acid sites (L252 and C278) in PP2A-C through mutations that prevented MC-LR binding without affecting PP2A activity. This discovery was robustly validated through behavioral studies and neuronal calcium imaging using nematodes. In conclusion, we identified two crucial amino acid sites that could prevent MC-LR from binding to PP2A-C, which holds great significance for the future development of MC-LR detoxification drugs. [ABSTRACT FROM AUTHOR]

In this work, we characterised the cyanobacterial communities in the plankton and littoral biofilm of 38 lakes and in the biofilm of 21 rivers in the Alps and surrounding subalpine regions by 16S rRNA gene metabarcoding. We found little overlap in the distribution of amplicon sequence variants (ASVs) between the three habitats and between water bodies. The differences were caused by environmental filtering acting on the selection of the most abundant ASVs and a high contribution of rare oligotypes. The differentiation of community and genotype composition from specific water bodies was explained to a significant extent by environmental variables and morphometry. The taxonomic consistency of ASVs classified under the same genus name was assessed by phylogenetic analyses performed on three representative dominant genera, namely Cyanobium, Tychonema and Planktothrix. The analyses revealed eco-evolutionary adaptations in lakes and rivers, including some evidence for a polyphyletic nature. Monitoring individual genotypes in relation to environmental conditions will be useful to define the ecological amplitude of these taxa. However, the persistence or ephemeral nature of some of the rarest and most unusual ASVs has remained unknown. [ABSTRACT FROM AUTHOR]

In this study, we employ in situ, meteorological, and remote sensing data to estimate chlorophyll-a concentration at different depths in a South American freshwater ecosystem, focusing specifically on a lake in southern Chile known as Lake Maihue. For our analysis, we explored four different scenarios using three deep learning and traditional statistical models. These scenarios involved using field data (Scenario 1), meteorological variables (Scenario 2), and satellite data (Scenarios 3.1 and 3.2) to predict chlorophyll-a levels in Lake Maihue at three different depths (0, 15, and 30 m). Our choice of models included SARIMAX, DGLM, and LSTM, all of which showed promising statistical performance in predicting chlorophyll-a concentrations in this lake. Validation metrics for these models indicated their effectiveness in predicting chlorophyll levels, which serve as valuable indicators of the presence of algae in the water body. The coefficient of determination values ranged from 0.30 to 0.98, with the DGLM model showing the most favorable statistics in all scenarios tested. It is worth noting that the LSTM model yielded comparatively lower metrics, mainly due to the limitations of the available training data. The models employed, which use traditional statistical and machine learning models and meteorological and remote sensing data, have great potential for application in lakes in Chile and the rest of the world with similar characteristics. In addition, these results constitute a fundamental resource for decision-makers involved in the protection and conservation of water resource quality. [ABSTRACT FROM AUTHOR]

Environmental biomonitoring techniques have been widely applied to assess the quality states of toxic chemical compounds in surface freshwater quality. The methods based on macrophytes are generally recruited to present trustworthy assessments of ecological status for surface water bodies. The chief goal of the present investigation was to improve robust machine learning models (MLMs) to establish relationships among macrophyte indices and the simultaneous effects of water quality parameters (WQPs) and hydromorphological factors. In the present research, the dataset included monthly WQPs, which have been accumulated from 200 sample points located in the bottomland of studied rivers, placed in Poland. This research utilized three ecological indices, namely the macrophyte index for rivers (MIR), the macrophyte biological index for rivers (IBMR), and river macrophyte nutrient index (RMNI) whereas species richness (N) and Simpson index (D) were considered as diversity indices. 12 WQPs and two hydromorphological indices have been considered as input variables for the MLMs namely gene-expression programming (GEP), evolutionary polynomial regression (EPR), multivariate adaptive regression spline (MARS), and model tree (MT). In terms of the best performance of MLMs' results, RMNI predictions were obtained by EPR (correlation coefficient [R] = 0.6061 and root mean square error [RMSE] = 0.5355) whereas MIR, IBMR, species richness, and Simpson index were predicted by MARS (R = 0.4333 and RMSE = 11.5046), EPR (R = 0.6020 and RMSE = 1.6923), GEP (R = 0.6089 and RMSE = 7.7229), and MARS (R = 0.5066 and RMSE = 0.2217), respectively. The great impact of these indexes was evaluated by the statistical parameters. This study showed that the biological assessment of rivers through macrophyte indexes not only helps to broaden knowledge related to the ecological status of the river but also aids in managing natural and anthropogenic activities' impacts on the water body. [ABSTRACT FROM AUTHOR]

Non-indigenous species (NIS) contribute to the decrease of native species' diversity on a local and global scale. One of Europe's most significant donors of freshwater invasions is the Ponto-Caspian Region. Following the construction of artificial canals connecting isolated waterbodies and the resulting heavy boat traffic, the Ponto-Caspian Amphipoda started to spread in Europe. Four amphipod species: Dikerogammarus haemobaphes, Dikerogammarus villosus, Pontogammarus robustoides and Chaetogammarus ischnus have invaded the Masurian Lakeland (North-eastern Poland). Based on literature and our data, we studied their distribution in 22 lakes in the region during the years 2001-2016. We analysed their distribution against several water quality parameters and levels of anthropogenic pressure. Our results also present the first records of two new invaders, D. villosus and C. ischnus, in the studied area. We show that the relative abundance and frequency of these two species rapidly increase and, simultaneously, the populations of the earlier invaders, i.e. D. haemobaphes and P. robustoides, decrease. The native species - Gammarus lacustris - seems to be negatively affected by NIS richness, as well as by the proximity of towns. The spread of NIS in the lakes appears to be facilitated by boating and the lower complexity of the shoreline. Our study shows how anthropogenic pressure, especially tourism, can facilitate bioinvasion, jeopardising native biodiversity unless appropriate regulations are implemented. [ABSTRACT FROM AUTHOR]

Large lowland rivers represent an important type of ecosystem that has been under a constant anthropogenic influence (industry, thermal power plants, untreated communal water, and agriculture) for centuries, which has led to most of them no longer meeting natural reference conditions. These pressures affect diatom communities which represent a reliable bioindicator of the overall degradation of water bodies. The current study provides detailed information about benthic diatoms from the large international lowland rivers Sava and Tisa, analyzed using digital microscopy. Using the digital method and the BIIGLE 2.0 image annotation system, a total of 205 and 206 diatom taxa in the Sava and Tisa rivers were identified, belonging to 65 and 63 genera, respectively. Some of the dominant genera in the Sava River were Achnanthidium, Cocconeis, Gyrosigma, and Navicula, while in the Tisa River, mostly centric diatoms (Discostella, Cyclotella, Stephanodiscus) were dominant. Most of the recorded species are alkaliphilic and characteristic of running waters with high trophic conditions. The presence of halophilic taxa was also noted (e.g. Bacillaria paxilifera, Tryblionella species, Nitzschia clausii, Navicula salinarum). These taxa are sensitive indicators of even short-term changes in lowland lotic ecosystems characterized by elevated conductivity. The diatom indices showed very consistent ecological status, mainly moderate in terms of the general pollution index IPS, and poor to bad ecological status according to trophic diatom indices (Rott TI and TDI). [ABSTRACT FROM AUTHOR]

The main objective of this work is to propose a new technique for water quality parameters monitoring by applying artificial intelligence methods to optimize remote sensing data processing. A multiple regression model was developed to create a total suspended solids (TSS) prediction model, using unsupervised machine learning. Currently, water bodies throughout the world are poorly supervised in terms of quality, so it is necessary to implement efficient mechanisms to obtain synoptic information for a good diagnosis in TSS evolution, because they are a key indicator of the biophysical state of lakes and an essential marker for continuous monitoring. Conventional methods used to monitor the physical parameters of water bodies, for example, in situ sampling, have proven impractical due to time, cost and space constraints, and remote sensing tools can help to achieve this purpose more efficiently. The proposed multiple regression model requires calibration and to that end, Lake Chapala data from the monitoring time series collected by the National Water Commission (CONAGUA) were used. Lake Chapala is the largest freshwater body in Mexico, and the human intervention that develops around the lake has caused drastic changes such as decrease in the size of the lake and increase in suspended matter and aquatic vegetation. These changes alter the balance of the system, endangering the health of the lake. This work presents a generalized semi-empirical model that uses Landsat image data and machine learning methods for estimating total suspended solids (TSS) in water bodies, with a good prediction precision (R = 0.81, RMSE = 32.52). [ABSTRACT FROM AUTHOR]

The interaction between climate warming and alien fish invasions could have severe consequences in inland waters, which represent isolated environments with high biodiversity richness. Due to the current climatic trend, increasing water temperatures and salinization, shorter ice cover period, and altered flow regimes are predicted for these environments. The aim of this review is to offer a comprehensive analysis at a global scale of the recent studies available in the literature, focused on the responses of invasive freshwater fish to the effects of climate change in both lotic and lentic environments. To achieve this purpose, we selected 34 relevant papers, using the Scopus and Google Scholar database. New alien species establishment, distribution range expansion of species already introduced, and exacerbating impacts on freshwater ecosystems and the native fish communities they host were included in the topics covered by the analyzed papers. Despite the uncertainties related to the unpredictability with which the effects of global warming will occur, the findings of the selected studies served as a support to evaluate conservation and management implications, with particular reference to possible mitigation strategies. [ABSTRACT FROM AUTHOR]

The terms 'non-native', 'non-indigenous', 'alien', and 'exotic' refer to species or races that do not occur naturally in an area, i.e., they have not previously existed there, or their dispersal into the area has been mediated by humans. In a broad sense, these terms can refer to species that may originate within the same region or country but not occur naturally in a particular water body until colonization is facilitated by humans. In Bulgaria, some efforts have been made to summarize the distribution of alien fish species, but nothing is known about the translocated species. Here, both groups are considered according to the Water Framework Directive's (WFD) classification of lotic ecosystems: the main ichthyogeographical regions, the river typology, and the ecological status of the Biological Quality Element (BQE) "Fish". In total, 7 alien species and 15 translocated species were established, with approximately the same total number of specimens. In general, even though the relative abundance of non-native species reaches 100% in single cases, their total numbers are low, compared to native species. Concerning certain basins/river types, these percentages are slightly higher, due to a complex of parameters determining their distribution: environmental factors (hydromorphological) reflecting the ecological (species' requirements and tolerance) factors. Some river types are more vulnerable to colonization. The relative abundances of the non-native fish species per sampling site showed a weak connection with the ecological status of the BQE "Fish". As the distribution of organisms is affected by environmental parameters and biotic interactions, standardized multiannual data, as viewed by the WFD, could become a solid basis for elucidating various aspects of this complex issue. [ABSTRACT FROM AUTHOR]

Countries with heterogeneous climatic and geographic characteristics may find it challenging and limiting to fulfill the requirements of the Water Framework Directive (WFD), such as defining ecoregion and water body types. To overcome this limitation, they implement optional factors in addition to the obligatory factors defined in the WFD. As a candidate country, Türkiye is required to comply with the WFD requirements and must determine its own optional and obligatory factors. In this context, we addressed the relevance of Chironomus spp. in determining these factors. We used twenty distinct national lake typologies for Türkiye and identified a total of 24 Chironomus species. The Chironomus genus was found to be effective in determining the optional factors. Statistical analyses revealed that fetch, altitude, salinity, water temperature, pH, saturated and dissolved oxygen, conductivity, orthophosphate, ferrous ion, chloride, and nitrogen compounds were significant in discriminating the regions. The canonical correspondence analysis (CCA) explained 56.62% of the variance. We also statistically analyzed the effectiveness of the class boundaries of the obligatory factors used in Türkiye for regionalization. Among the official obligatory factors, only the altitude boundaries gave a significant result and explained a total of 62% variance. We recommend revising the class boundaries of obligatory factors and using fetch data as a significant genuine parameter for lake typology as an optional factor [ABSTRACT FROM AUTHOR]

A total of 385 species of diatoms were identified in the phytoplankton of 14 small Arctic tundra water bodies in the vicinity of Tiksi Bay. We found that the species composition of phytoplankton in each lake is strictly individual. The ecological preferences of diatom species in the studied water bodies were determined for more than 90% of the list. Indicator characteristics show a certain response of the species composition of phytoplankton to changes in salinity and organic pollution. Several regularities were revealed in the spatial distribution of diatom communities in the study area in connection with the physicochemical parameters of their habitat, the height of the lake, its remoteness from the seacoast, and belonging to a specific watershed. Statistical mapping of the data on the diversity of communities and the chemical properties of water revealed a strong reaction of the communities of water bodies to point one-time anthropogenic pollution, and also made it possible to assume the influence of summer, northeast winds on the species composition as a climatic factor. The results of the study are important for developing the foundations for monitoring the non-impact (background), ecologically sensitive territory of the Arctic. They are highly relevant for assessing the consequences of local anthropogenic impacts and climate change in the future. Spatial ecological mapping in conjunction with bioindication can be used as a new method for identifying natural and non-natural stress factors. [ABSTRACT FROM AUTHOR]

This research demonstrated the feasibility of applying Sentinel-2 images to generate empirical models and estimate physicochemical parameters concentration, particularly nutrients in the wetland system called Bajo Sinú wetlands complex, Colombia. Spearman correlations were determined between water quality parameters, which were monitored at 17 points in the wetland on 5 February 2021, with Sentinel-2 images reflectance values from the same monitoring date; the correlations allowed the identification of statistically significant bands in the multiple linear regression algorithm implementation to determine empirical water quality models. The results show significant correlations between the optically active parameters, TSS-Turbidity, which in turn correlated with the optically inactive parameters Turbidity-NO3 and TSS-DO, as well as non-optically active parameters among themselves, TDS-NO3 and TDS-TP; the empirical models presented higher than 74.5% fit (R2), particularly DO (R2 = 0.948), NO3 (R2 = 0.858) and TP (R2 = 0.779) were the models with the highest fits (R2). These models allowed us to properly estimate the spatial distribution of nutrient-forming compounds in the wetlands complex. The determinant role played by turbidity in this type of water body is highlighted; it acts as a connecting constituent that makes the estimation of water quality parameters without spectral response through remote sensing feasible. Sentinel-2 images and multiple linear regression algorithms have been shown to be effective in estimating the concentration of water quality parameters without spectral response, such as NO3 and TP in shallow tropical wetlands, due to the processes of transformation, interaction and dependence between the different environmental variables in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Nutrient pollution may negatively affect the water quality and ecological status of rivers and estuaries worldwide, specifically in stratified and small inland estuaries. We present a long-term, two-decade data set of dissolved inorganic nutrient concentrations, chlorophyll-a (chl-a), dissolved oxygen (DO), and potentially toxic algal cell concentrations at the Kishon River estuary (Israel) as a case study for assessing nutrient ecological thresholds in such type of estuaries, prevalent along the Mediterranean coast of Israel. In-situ measurements and water samples were collected at 3 permanent stations at the lower part of the estuary every March and October/November in 40 campaigns over the years 2002 to 2021. In spite of an improvement in nutrient loads and concentrations as recorded over the last 2 decades, the nutrient and chl-a levels at the Kishon estuary surface water represent mostly a 'bad' or 'moderate' ecological state, considering the recommended thresholds discussed in this study. It is suggested to develop a combined suite of nutrient and biological variables for assessing Good Environmental Status (GES), considering the relatively high residence time of such small, low-flow estuarine water bodies. [ABSTRACT FROM AUTHOR]

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Flow variability determines the conditions of river ecosystems and river ecological functioning. The variability of ecological processes in river ecosystems gradually decreases due to river channelization and incision. Prediction of the environmental flow allows us to keep biological diversity and river health developed as a response to the degradation of aquatic ecosystems overexploited by humans. The goal of the study was to test the influence of river incision on environmental flow estimation based on the Biological Monitoring Working Party (BMWP) macroinvertebrate index. A total of 240 macroinvertebrate assemblages of 12 waterbodies differing in bed substrate and amplitude of discharge were surveyed in southern Poland. Variations in the distribution of 151 466 macroinvertebrates belonging to 92 families were analysed. The similarity of benthic macroinvertebrates reflects the typological division of the rivers into three classes: Tatra mountain streams, mountain flysch rivers, and upland carbonate and silicate rivers. As a response variable reflecting the macroinvertebrate distribution in the river, the BMWP_PL index was chosen. The river incision significantly increased the values of e-flow calculations in relation to redeposited channels. The area of optimal habitat for macroinvertebrates decreased with the bed incision intensity. In highly incised rivers, the environmental flow values are close to the mean annual flow, suggesting that a high volume of water is needed to obtain good macroinvertebrate conditions. As a consequence, river downcutting processes and impoverishment of optimal habitats will proceed. [ABSTRACT FROM AUTHOR]

From 2018 to 2019, a survey of a typical lakes system in the Taihu Lake basin, China, was carried out. To provide reference values for the restoration and management of submerged vegetation in the lakes, the optical attenuation coefficient (Kd) and euphotic depth (Zeu) of the water body were calculated, and the distribution characteristics and factors that influenced the underwater optical field lands with different nutrition levels in the basin were analyzed. The main factor affecting the distribution of photosynthetically active radiation (PAR) in lakes in the Taihu Lake basin is suspended solids (SS), dominated by inorganic suspended matter (ISS). Chlorophyll a (Chl-a), dissolved organic carbon (DOC), and chromophoric dissolved organic matter (CDOM) all affect, although weakly, the optical characteristics of lake wetlands. In CDOM, humic-like components have a more significant impact on Kd. The Kd of lakes in the Taihu Lake basin is closely related to permanganate index (CODMn) and especially total phosphorus (TP); The growth of aquatic vegetation is increased in Shanghu, Dianshan-Yuandang, Yangcheng, and Wuli Lakes that have higher Zeu and Zeu/Depth values. [ABSTRACT FROM AUTHOR]

Simple Summary: The humic lake represents a special kind of aquatic ecosystem with high humic substances, low irradiance, and a high potential for greenhouse gas emissions. Despite the special environment and biogeochemical processes in humic lake water, knowledge about the underlying microbial-driven functions remains elusive. Here, we studied the compositions and functional gene structures of microbial communities in a humic lake (HL) and a reference weakly alkaline lake (RAL). We found that the high organic matter content in the HL supported higher gene diversity; and, specifically, the carbon and nitrogen fixations, the degradation of various types of carbon, methane oxidation and methanogenesis, ammonification, denitrification, and assimilatory N reduction might be enhanced more in the HL than in the RAL. By contrast, the humic fractions in the HL might reduce microbial metabolic potential for sulfur oxidation and phosphorus degradation. The potential interactions between different functional microorganisms might be down-regulated provided that there were more easily acquired nutrients in the HL. Overall, our results showed the functional gene "landscape" of microbial communities in the surface water of a humic lake, which helps understand the biogeochemical processes and the remediation of organic matter pollution in lacustrine ecosystems. Humic lakes (HLs) are special water bodies (high organic matter content, low pH, and low transparency) that are important sources of major greenhouse gases. The knowledge about microbial functional potentials and the interactions among different genes in HL water has been scarcely understood. In this study, we used 16S rRNA gene sequencing and the GeoChip 5.0 to investigate microbial community compositions and functional gene structures in an HL and a reference weakly alkaline lake (RAL). The HL microbial communities showed distinct compositions and functional gene structures than those in the RAL. The functional gene diversity was significantly higher in the HL than in the RAL. Specifically, higher gene relative intensities in carbon and nitrogen fixations, the degradation of various types of carbon, methane oxidation and methanogenesis, ammonification, denitrification, and assimilatory N reduction were observed in the HL samples. By contrast, the metabolic potentials of microorganisms involved in dissimilatory N reduction, phosphorus degradation, and sulfur oxidation were weaker in the HL than in the RAL. Despite higher functional gene diversity, the interaction efficiency among genes (reflected by network geodesic distance and clustering coefficient) might be reduced in the HL. Different functional microbes may develop less interdependent relationships in acquiring nutrients given the high resource availability in the HL. Overall, the enhanced microbial metabolic potentials and less efficient functional interactions might have great consequences on nutrient cycling and greenhouse gas emissions in the HL ecosystem. [ABSTRACT FROM AUTHOR]

The European Union enforces the member states designate sensitive areas and nitrate vulnerable zones according to Water Framework Directive and its daughter directives Nitrates Directive and Urban Wastewater Treatment Directive. The aim of this study is to develop an approach for designation of sensitive areas (SAs) and nitrate vulnerable zones (NVZs) for surface water bodies. SAs are designated with a three‐step approach using initial characterization, physicochemical monitoring, and application of biotic indices. Nitrate concentration data of monitoring stations and the total nitrate loading rates of agriculture were two parameters for the determination of NVZs. This simplified methodology was applied to Yesilirmak River Basin. A total of 42 water bodies (23 river and 19 lake) were specified as SA and 30 water bodies (17 river and 13 lake) were designated as NVZ which constitutes about 63% and 49% of the total drainage area of the basin, respectively. Although the final definition of SAs and NVZs will depend on policies and regulations adopted in Turkey, the study contributed to efforts of Turkish water authorities for the determination of the SAs and NVZs of Turkey. [ABSTRACT FROM AUTHOR]

This paper presents data compilation for invertebrates and protists indicator taxa of organic pollution and trophic state of continental waters. Information was collected from research papers, monographs, electronic resources, and our own research. Altogether 1732 indicator taxa of Kingdoms Protista, Protozoa, Chromista, and Animalia from 19 taxonomical Phyla are represented with ecological preferences for saprobity with saprobity index (S) and trophic state. This comprehensive data can be used for the purpose of aquatic ecosystem assessment and monitoring of water quality based on bioindication methods. [ABSTRACT FROM AUTHOR]

Although the Mediterranean area is a well-known hotspot of biological diversity, the crustacean assemblages inhabiting inland waters of the Mediterranean islands are to date unevenly known, and detailed information is missing for most taxa and areas. In the frame of this paper, we provide a checklist and a characterization of the copepod fauna of the lentic water bodies occurring in a traditional rural landscape of Sicily, where the co-existence of agriculture, woodlands, and pastoral activities lead to the presence of a wide range of different aquatic habitats. Overall, 22 copepod species belonging to the orders Calanoida, Cyclopoida, and Harpacticoida have been found in the 92 surveyed sites, stressing the conservation value of the area. In the study area, species widespread in the west Palaearctic region co-exist with strictly Mediterranean elements and a small but biogeographically significant group of species with northern or Balkan affinities, which support the role of the investigated area as a refugium for species that colonised Sicily during Pleistocene climate fluctuations and are now restricted to the more wet parts of the island. A single non-native species has been found, and its distribution is currently limited to permanent, man-made reservoirs. [ABSTRACT FROM AUTHOR]

The decline of freshwater flora due to alteration, reclamation and trophic perturbation of lowland wetlands is among the most relevant issues in biological conservation. The contribution of heavily modified water bodies (HMWBs) in preserving plant diversity is notable, but the underlying ecological mechanisms are not completely explored. To contribute to this debate and expand the knowledge on the role of HMWBs in maintaining wetland biodiversity in overexploited agroecosystems, a canal network of about 1150 km (SE Po valley, N-Italy) was analysed to study the geographical patterns of riparian flora and plant communities, and their land use and hydrochemical drivers. A systematic sampling procedure was adopted by randomly selecting 96 transects (10 m2) along 79 drainage canals. Additionally, 22 transects were sampled for water quality evaluation. Flora was characterised based on species richness and presence of threatened, alien and invasive species. We also studied the contribution of land use and water quality in explaining plant richness and composition. Slope and aspect of canals do not significantly affect plant species composition, whereas the «proximity to protected areas» seems to have a negative influence. Both threatened and alien plants richness decrease approaching protected areas. Among land use types, only agro-zootechnical settlements influence plant species composition, favoring nitrophilous species, as demonstrated by water parameters (the spatial patterns of nitrophilous species mirrored the progressive worsening of canal waters). This work confirms the key role of HMWBs in sustaining plant species diversity in oversimplified landscapes, highlighting complex regulation mechanisms that need further investigations. [ABSTRACT FROM AUTHOR]

A massive shift in agricultural practices over the past decades, to support exceptionally high yields and productivities involving intensive agriculture, have led to unsustainable agriculture practices across the globe. Sustenance of such high yields and productivities demand high use of organic and industrial fertilizers. This acts as a negative pressure on the environment. Excessive use of fertilizers leads to nutrient surplus in the fields, which, as a part of catchment runoff, flows into the water bodies as diffuse pollution. These nutrients through rivers are eventually passed into seas. High nutrients ending up into water bodies cause eutrophication. The situation is worsened when such unsustainable agricultural activities are carried out on drained peatlands. As a result, the nutrients that were not part of the nutrient cycle in the landscape for years begin to leach out due to mineralization of peatlands, thereby putting an additional load of nutrients on the environment, that was already under the negative impact of nutrient surplus. In view of the above, a small lowland catchment of the Ryck river in northeast Germany was assessed for its nitrogen losses from agricultural lands through empirical modelling. Initial empirical modelling resulted in an average annual total nitrogen loss of 14.7 kg ha−1 year−1. After a comparative analysis of these results with procured data, the empirical equation was modified to suit the catchment, yielding more accurate results. The study showed that 75.6% of peatlands in the catchment are under agricultural use. Subsequently, a proposal was made for potential wetland buffer zones in the Ryck catchment. Altogether, 13 peatland sites across 8 sub-catchments were recommended for mitigation of high nutrient runoff. In the end, nutrient efficiency of proposed WBZs in one of the sub-catchments of Ryck has been discussed. The results show that (i) the modified empirical equation can act as a key tool in application-based future strategies for nitrogen reduction in the Ryck catchment, (ii) restoration of peatlands and introduction of WBZs can help in mitigating the nutrient runoff for improved water quality of Ryck, and subsequently (ii) contribute to efficient reduction of riverine loads of nutrients into the Baltic Sea. [ABSTRACT FROM AUTHOR]

Artificial and natural water bodies, such as reservoirs, ponds, rivers and lakes, are important components of water-related ecosystems; they are also important indicators of the impact of human activities and climate change on surface water resources. However, due to the global and regional lack of artificial and natural water bodies data sets, understanding of the changes in water-related ecosystems under the dual impact of human activities and climate change is limited and scientific and effective protection and restoration actions are restricted. In this paper, artificial and natural water bodies data sets for China are developed for the years 2000, 2005, 2010, 2015 and 2020 based on satellite remote sensing surface water and artificial water body location sample data sets. The characteristics and causes of the temporal and spatial distributions of the artificial and natural water bodies are also analyzed. The results revealed that the area of artificial and natural water bodies in China shows an overall increasing trend, with obvious differences in spatial distribution during the last 20 years, and that the fluctuation range of artificial water bodies is smaller than that of natural water bodies. This research is critical for understanding the composition and long-term changes in China's surface water system and for supporting and formulating scientific and rational strategies for water-related ecosystem protection and restoration. [ABSTRACT FROM AUTHOR]

Water body mapping is an effective way to monitor dynamic changes in surface water, which is of great significance for water resource management. Super-resolution mapping is a valid method to generate high-resolution dynamic water body maps from low-spatial-resolution images. However, the accuracy of existing super-resolution mapping methods is not high due to the low accuracy of fraction images and the insufficiency of spatial pattern information. To solve this problem, this paper proposes a spectral similarity scale-based multiple-endmember spectral mixture analysis (SSS-based MESMA) and a multiscale spatio-temporal dependence method based on super-resolution mapping (MESMA_MST_SRM) for water bodies. SSS-based MESMA allows different coarse pixels to have different endmember combinations, which can effectively improve the accuracy of spectral unmixing and then improve the accuracy of fraction images. Multiscale spatio-temporal dependence adopts both pixel-based and subpixel-based spatial dependence. In this study, eight different types of water body mappings derived from the Landsat 8 Operational Land Imager (OLI) and Google Earth images were employed to test the performance of the MESMA_MST_SRM method. The results of the eight experiments showed that compared with the other four tested methods, the overall accuracy (OA) value, as well as the overall distribution and detailed information of the water map generated by the MESMA_MST_SRM method, were the best, indicating the great potential and efficiency of the proposed method in water body mapping. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Environmental Protection is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Researchers, policymakers, and governments are increasingly interested in assessing the ecological health (EH) of lakes and streams. The EH of a lake can be expressed in terms of water quality, trophic state and biodiversity of riparian vegetation, macroinvertebrates and fishes. The ecological health index (EHI) of Renuka lake, Himachal Pradesh of India, was analyzed based on National Sanitation Foundation Water Quality Index (NSFWQI), Carlson's Trophic State Index (TSI), Simpson Diversity Index (SDI), and Shannon-Weiner index (SWI). The results of NSFWQI and CTSI are found in the range of 40-59 and 49.9-58.9 respectively indicating that the water quality was poor to medium and not suitable for drinking purposes but can be used for secondary purposes such as agriculture, industry, and recreation etc. The trophic state of the lake is similarly in the eutrophic range, with an overall EHI of 1.81-2.47, indicating poor to medium trophic status. Apart from analyzed results, the EH category from mesotrophic to a eutrophic state of the lake is caused due to the cultural siltation/nutrient loading, religious practices, land tenurial issues, and uncontrolled tourist pressure followed by recreational activities on water bodies and lake vicinity. Accordingly, suitable restoration methods such as source control, desilting/dredging, and lake aquatic plantation are suggested to recover the ecological health of the lake back to a mesotrophic or oligotrophic state. [ABSTRACT FROM AUTHOR]

The Lake Habitat Survey for Polish Lakes (LHS_PL) is a method for the hydromorphological investigation of lakes employed for the assessment of the ecological status of surface water bodies in Poland. It was developed based on the British Lake Habitat Survey method. In 2015, after almost a decade of work on the adaptation, the LHS method was finally adjusted to Polish conditions, and since 2016, it has been implemented in the State Environmental Monitoring programme. This paper presents the assumptions and evolution of the method and the approach for determining boundary values for the high/good (H/G) and good/less than good (G/LTG) ecological status classes. The method involves the assessment of the morphological features of the lake and anthropogenic pressures at 10 observation plots as well as the analysis of hydrological alterations and anthropogenic activities within the lake basin and the entire catchment area. The data collected in the field are used to calculate the index of lake hydromorphological alteration, that is, the Lake Habitat Modification Score for Polish Lakes (LHMS_PL). The LHMS_PL values range from 0 to 144, where 0 means no modification and 144 refers to a hydromorphologically highly modified state. The boundary values for the H/G and G/LTG status classes have been determined using the quartile method based on the relationship between hydromorphological modifications of lakes and the condition of the phytoplankton and macrophyte communities therein. [ABSTRACT FROM AUTHOR]

Freshwater conservation is vital to the maintenance of global biodiversity. Ponds are a critical, yet often under‐recognized, part of this, contributing to overall ecosystem functioning and diversity. They provide habitats for a range of aquatic, terrestrial, and amphibious life, often including rare and declining species.Effective, rapid, and accessible survey methods are needed to enable evidence‐based conservation action, but freshwater taxa are often viewed as "difficult"—and few specialist surveyors are available. Datasets on ponds are therefore limited in their spatiotemporal coverage.With the advent of new recording technologies, acoustic survey methods are becoming increasingly available to researchers, citizen scientists, and conservation practitioners. They can be an effective and noninvasive approach for gathering data on target species, assemblages, and environmental variables. However, freshwater applications are lagging behind those in terrestrial and marine spheres, and as an emergent method, research studies have employed a multitude of different sampling protocols.We propose the Pond Acoustic Sampling Scheme (PASS), a simple protocol to allow a standardized minimal sample to be collected rapidly from small waterbodies, alongside environmental and methodological metadata. This sampling scheme can be incorporated into a variety of survey designs and is intended to allow access to a wide range of participants, without requiring complicated or prohibitively expensive equipment.Adoption of this sampling protocol would enable consistent sound recordings to be gathered by researchers and conservation organizations, and allow the development of landscape‐scale surveys, data sharing, and collaboration within an expanding freshwater ecoacoustic community—rather than individual approaches that produce incompatible datasets. The compilation of standardized data would improve the prospects for effective research into the soundscapes of small waterbodies and aid freshwater conservation efforts. [ABSTRACT FROM AUTHOR]

Monitoring changes in natural ecosystems is considered essential to natural resource management. Despite the global importance of the lakes' quality monitoring, there is currently a research gap in the simultaneous predictive modeling of lakes' land-use changes and ecosystem measurements. In the present study for projecting the water bodies of lakes and their surrounding ecosystems, the land-use changes and the landscape analysis of different periods, i.e., 1987, 2002, 2018, and 2030, are studied using remote sensing data and various metrics. The trend of land-use and landscape changes is projected for 2030. The results indicate significant degradation of rangelands and forests due to the conversion to agriculture and construction and the declining trend of lakes' water body and their transformation to salt lake and salt lands. The increase of agricultural lands and the overuse of groundwater wells upstream of the lakes could be one of the reasons for this decline. Decreasing the lakes' water body and subsequently increasing salt lands are considered a severe threat to human health and the ecosystem services of the lakes. Besides, the dust generated by salt lands could also decrease crop yield in the study area. [ABSTRACT FROM AUTHOR]

Microbial communities in surface waters used for recreational purposes are indicators of contamination and risk of contact with human pathogens. Hence, monitoring microbial communities in recreational waters is important for potential public health threats to humans. Such monitoring is rare in Colombia, even in its capital, Bogotá, the most populous city in the country. This city encompasses metropolitan and linear parks with recreational water bodies that are used frequently by the public, and the presence of pathogens can compromise the health of the citizens. Therefore, we examined the bacterial, and eukaryotic communities in urban recreational lakes (URL) in four metropolitan parks in Bogotá, Colombia. Samples from four metropolitan parks (Los Novios, Simon Bolivar, El Tunal, and Timiza) and one stream contaminated with sewage from a linear park (El Virrey) were collected. We used amplicon next-generation sequencing of the 16S-rRNA gene and 18S-rRNA gene to characterize microbial communities followed by bioinformatics analyses. In addition, general water quality parameters—pH, hardness, acidity, alkalinity, dissolved oxygen, and nitrites—were recorded using a commercial kit. Genera of pathogens, including Legionella, Pseudomonas, Mycobacterium, Candida, and Naegleria, were found in lake waters. The stream El Virrey was, however, the only surface water that showed an abundance of fecal bacteria, often associated with low oxygen concentrations. All water bodies showed a predominance of fungal phyla, except for the lake at Timiza. This lake showed the highest pH, and its ecological dynamics are likely different from other water bodies. Likewise, some URLs displayed a greater abundance of cyanobacteria, including toxin-producing species. Algal genera associated with eutrophication were predominant among primary producing microorganisms. This study shows for the first time the description of the bacterial and eukaryotic communities of some URLs and a stream in Bogotá. The URLs and the stream harbored various pathogens that might pose a risk to the citizen's health. [ABSTRACT FROM AUTHOR]

The Government of the Republic of Armenia (RA) strives to ensure the measures to achieve good ecological status for Armenian surface water bodies. However, the main goal remains unaccomplished, as the hydro-biological monitoring tools are not properly developed. Thus, the current work aims at contributing to the establishment of principles and a relevant and cost-effective biological monitoring tool for the RA aquatic ecosystems, through the development of a simplified multimetric index (MMI). Since the adoption of the decree N° 927-N from 11 Jun 2011, the baseline studies have been initiated in the six river basin management areas established in the RA. The current work is summing up the results for the Arpa River system in order to test the methodology. In particular, it is testing the possibility to develop MMI based on the use of Rapid Biological Assessment protocol accepted in our monitoring system. Also, the work represents the approach of bottom-up biotic validation of reference sites established in the recent hydro-biologic monitoring system. Due to the proposed validation procedure, further use of one of the established reference sites in the case study object has been rejected. Considering well-established approaches for MMI development in EU member states, four variations of MMI were developed for a particular river system, and the combination of Ntaxa-%EPT-Abundance(ind/m2)-BMWP-ASPT-FBI-Nfamily metrics has been proposed as the main one. However, further development of a river typology and the establishment of joint reference conditions in the Caucasus region have concluded as a priority. [ABSTRACT FROM AUTHOR]

Featured Application: The LUPLES method, explained in this paper, allows for the estimation of the level of pressures to which lentic waterbodies are exposed from land uses in the catchment area and direct alterations in their basin. The method can be used to approach the intensity of pressures and the possible effects of land uses in the catchment (and its changes) on the ecological status of lentic waterbodies, as having being validated by the correlation of the LUPLES estimated pressure levels with the metrics measuring impacts according to the Water Framework Directive. The features of lentic waterbodies largely depend on the surrounding environment. Mediterranean coastal lagoons have been historically altered, with their catchment being highly modified for agricultural, livestock, or urban uses. Changes in land uses induce pressures that impact the waterbodies and alter their ecological status. The objectives of this paper were: to develop a methodological approach (LUPLES: Land Uses for estimating Pressure Levels to approach the Ecological Status), to quantify the main pressures on the waterbodies and to forecast the possible impacts of these pressures on their ecological status. Corine-Land Cover maps and Geographic Information System technics were used to delineate and identify land uses in the catchments. Specific algorithms were created to quantify the main pressures from land uses in the catchment and hydro-morphological alterations in the immediate basin. The values of the estimated pressure levels were correlated with ecological status indicators using metrics developed for the European Water Framework Directive. Data were obtained from European and River Basin Authorities databases. Results showed statistically significant correlations between the pressure levels quantified by the LUPLES method and the impact level detected by biological, physical and chemical metrics. This method provides a useful approach to estimate the pressure levels affecting lentic waterbodies and could be applied to approach how they could affect their ecological status. [ABSTRACT FROM AUTHOR]

The biological assessment of rivers i.e., their assessment through use of aquatic assemblages, integrates the effects of multiple-stressors on these systems over time and is essential to evaluate ecosystem condition and establish recovery measures. It has been undertaken in many countries since the 1990s, but not globally. And where national or multi-national monitoring networks have gathered large amounts of data, the poor water body classifications have not necessarily resulted in the rehabilitation of rivers. Thus, here we aimed to identify major gaps in the biological assessment and rehabilitation of rivers worldwide by focusing on the best examples in Asia, Europe, Oceania, and North, Central, and South America. Our study showed that it is not possible so far to draw a world map of the ecological quality of rivers. Biological assessment of rivers and streams is only implemented officially nation-wide and regularly in the European Union, Japan, Republic of Korea, South Africa, and the USA. In Australia, Canada, China, New Zealand, and Singapore it has been implemented officially at the state/province level (in some cases using common protocols) or in major catchments or even only once at the national level to define reference conditions (Australia). In other cases, biological monitoring is driven by a specific problem, impact assessments, water licenses, or the need to rehabilitate a river or a river section (as in Brazil, South Korea, China, Canada, Japan, Australia). In some countries monitoring programs have only been explored by research teams mostly at the catchment or local level (e.g., Brazil, Mexico, Chile, China, India, Malaysia, Thailand, Vietnam) or implemented by citizen science groups (e.g., Southern Africa, Gambia, East Africa, Australia, Brazil, Canada). The existing large-extent assessments show a striking loss of biodiversity in the last 2–3 decades in Japanese and New Zealand rivers (e.g., 42% and 70% of fish species threatened or endangered, respectively). A poor condition (below Good condition) exists in 25% of South Korean rivers, half of the European water bodies, and 44% of USA rivers, while in Australia 30% of the reaches sampled were significantly impaired in 2006. Regarding river rehabilitation, the greatest implementation has occurred in North America, Australia, Northern Europe, Japan, Singapore, and the Republic of Korea. Most rehabilitation measures have been related to improving water quality and river connectivity for fish or the improvement of riparian vegetation. The limited extent of most rehabilitation measures (i.e., not considering the entire catchment) often constrains the improvement of biological condition. Yet, many rehabilitation projects also lack pre-and/or post-monitoring of ecological condition, which prevents assessing the success and shortcomings of the recovery measures. Economic constraints are the most cited limitation for implementing monitoring programs and rehabilitation actions, followed by technical limitations, limited knowledge of the fauna and flora and their life-history traits (especially in Africa, South America and Mexico), and poor awareness by decision-makers. On the other hand, citizen involvement is recognized as key to the success and sustainability of rehabilitation projects. Thus, establishing rehabilitation needs, defining clear goals, tracking progress towards achieving them, and involving local populations and stakeholders are key recommendations for rehabilitation projects (Table 1). Large-extent and long-term monitoring programs are also essential to provide a realistic overview of the condition of rivers worldwide. Soon, the use of DNA biological samples and eDNA to investigate aquatic diversity could contribute to reducing costs and thus increase monitoring efforts and a more complete assessment of biodiversity. Finally, we propose developing transcontinental teams to elaborate and improve technical guidelines for implementing biological monitoring programs and river rehabilitation and establishing common financial and technical frameworks for managing international catchments. We also recommend providing such expert teams through the United Nations Environment Program to aid the extension of biomonitoring, bioassessment, and river rehabilitation knowledge globally. [ABSTRACT FROM AUTHOR]

Eutrophication impact on key aquatic communities (phytoplankton, macrophytes and macrozoobenthos) was studied in three standing water bodies in Bulgaria (Kardzhali, Koprinka and Batak). The reservoirs had a high summer nutrient level and were between eu- and hypertrophic category. In the meso-eutrophic condition the highest number of phytoplankton species and functional diversity (Kardzhali Reservoir) and domination of functional groups (FGs) B, F, X3 and T were registered. The most intensive cyanobacterial growth was recorded in eu- to hypertrophic conditions (Koprinka Reservoir), as well as lower functional and species diversity, and domination of FGs M and J. Hydrological regime in hydroelectric reservoirs was a serious pressure for aquatic macrophytes and macrozoobenthos. Along the nutrient gradient, the Batak Reservoir had highest phytoplankton biovolume and macroinvertebrate taxa richness, well developed macrophyte community, dominated by eutrophication-tolerant species. The results suggested that measures for mitigating ecological impacts from pressures should be implemented without significant adverse effect on water use. [ABSTRACT FROM AUTHOR]

Reference conditions of water bodies are defined as the natural or minimal anthropogenically disturbed state. We compared the methods for determining total phosphorus and total nitrogen concentrations in rivers in Finland, Norway and Sweden as well as the established reference conditions and evaluated the possibility for transfer and harmonisation of methods. We found that both methods and values differed, especially for lowland rivers with a high proportion of agriculture in the catchment. Since Denmark has not yet set reference conditions for rivers, two of the Nordic methods were tested for Danish conditions. We conclude that some of the established methods are promising but that further development is required. We moreover argue that harmonisation of reference conditions is needed to obtain common benchmarks for assessing the impacts of current and future land use changes on water quality. [ABSTRACT FROM AUTHOR]

Artificial ponds assure continuous societal water supply, especially during droughts. Obligate aquatic and amphibiotic insects readily inhabit novel water bodies, as many possess mobility traits for opportunistic colonization. We review here the value of artificial ponds (< 2 ha) (and reservoirs; > 2 ha) for local aquatic insect diversity in mostly dry and drought-prone southern Africa. We compare these ponds to natural pools, wetlands, and stream deposition pools. The region has a highly varied topography and physiographical zones. Flat, arid areas largely support widespread insect generalists, while the mountainous orographic zones support an additional rich fauna of localized endemics. However, the many ponds (> 0.5 million) have greatly changed the local distribution patterns of surface freshwater across the region, increasing the area of occupancy for many aquatic insect species, especially dragonflies. We focus on the extent to which aquatic insect assemblages have benefitted from new ponds and reservoirs. We conclude that these novel ecosystems benefit almost all lentic aquatic insect species, while also enabling population resilience during droughts. However, while these benefits are substantial, these ponds are not a substitute for natural still waters, which are still required to maintain all indigenous lentic aquatic insect diversity. [ABSTRACT FROM AUTHOR]

Understanding patterns of beta diversity (heterogeneity) and its components (substitution and subset) is important for managing freshwater ecosystems and the research on these topics has increased over the last decade. However, there has been limited empirical research exploring the drivers of these components of beta diversity in ponds from agricultural landscapes, in which hydroperiod length is often a key structural driver. The purpose of our work was to examine the contribution of substitution (species replacement among sites without changes in richness) and subset (species differences among sites when species-poor sites constitute subsets of those with a greater number of taxa) structuring processes on macrophyte beta diversity patterns of sixteen permanent and ten temporary Mediterranean ponds. We also aimed to test the structuring role of local environmental factors and geographic isolation and to determine whether there are differences in the community heterogeneity and the relative importance of the substitution and subset fractions of beta diversity between permanent and temporary ponds. We found that temporary ponds were environmentally and biologically less heterogeneous and supported lower richness than permanent waterbodies. In both pond types, beta diversity almost entirely reflected patterns of species substitution rather than subsets. Local environmental conditions, and not among-pond distance, were the main drivers of macrophyte community structure. Overall, our results suggest that local environmental variables operating through niche processes were the primary mechanisms driving macrophyte beta diversity patterns, thus highlighting the importance of environmental heterogeneity for maintaining pond community diversity in agricultural landscapes. Accordingly, conservation initiatives and ecosystem management strategies should include permanent and temporary pond clusters comprising wide environmental gradients in their efforts to ensure high levels of regional biodiversity. [ABSTRACT FROM AUTHOR]

Controlling phosphorus is fundamental to limit the risk of eutrophication of continental aquatic ecosystems. Integrated modelling of its concentration in the aquatic continuum requires specific tools for water bodies. However, although simple static empirical models and complex biogeochemical models are numerous, there are few relatively simple and flexible models able to simulate seasonal variations in phosphorus concentrations in water bodies and particularly in reservoirs. In this study, the two-layer dynamic model, LakeMab, simulating phosphorus variations in water bodies, was enhanced to consider some tributary characteristics and reservoir specificities. It was then applied to the case of a reservoir in western France, Lake Bultière. Without any calibration, the modified model reproduced reasonably well seasonal variations in phosphorus concentration in the lake. A sensitivity analysis showed the importance of improvements related to reservoir functioning (outlet depth, water level fluctuations) and the smaller importance of those related to tributaries (variable concentrations, depth of riverine inputs). The model can easily be applied to diverse lentic systems and could be coupled to stream models, thereby making it a useful tool for managing water quality in lakes and reservoirs. [ABSTRACT FROM AUTHOR]

Artificial water bodies like ditches, fish ponds, weirs, reservoirs, fish ladders, and irrigation channels are usually constructed and managed to optimize their intended purposes. However, human-made aquatic systems also have unintended consequences on ecosystem services and biogeochemical cycles. Knowledge about their functioning and possible additional ecosystem services is poor, especially compared to natural ecosystems. A GIS analysis indicates that currently only ~ 10% of European surface waters are covered by the European Water Framework directive, and that a considerable fraction of the excluded systems are likely human-made aquatic systems. There is a clear mismatch between the high possible significance of human-made water bodies and their low representation in scientific research and policy. We propose a research agenda to build an inventory of human-made aquatic ecosystems, support and advance research to further our understanding of the role of these systems in local and global biogeochemical cycles as well as to identify other benefits for society. We stress the need for studies that aim to optimize management of human-made aquatic systems considering all their functions and to support programs designed to overcome barriers of the adoption of optimized management strategies. [ABSTRACT FROM AUTHOR]

The representativeness of aquatic ecosystem monitoring and the precision of the assessment results are of high importance when implementing the EU's Water Framework Directive that aims to secure a good status of waterbodies in Europe. However, adapting monitoring designs to answer the objectives and allocating the sampling resources effectively are seldom practiced. Here, we present a practical solution how the sampling effort could be re-allocated without decreasing the precision and confidence of status class assignment. For demonstrating this, we used a large data set of 272 intensively monitored Finnish lake, coastal, and river waterbodies utilizing an existing framework for quantifying the uncertainties in the status class estimation. We estimated the temporal and spatial variance components, as well as the effect of sampling allocation to the precision and confidence of chlorophyll-a and total phosphorus. Our results suggest that almost 70% of the lake and coastal waterbodies, and 27% of the river waterbodies, were classified without sufficient confidence in these variables. On the other hand, many of the waterbodies produced unnecessary precise metric means. Thus, reallocation of sampling effort is needed. Our results show that, even though the studied variables are among the most monitored status metrics, the unexplained variation is still high. Combining multiple data sets and using fixed covariates would improve the modeling performance. Our study highlights that ongoing monitoring programs should be evaluated more systematically, and the information from the statistical uncertainty analysis should be brought concretely to the decision-making process. [ABSTRACT FROM AUTHOR]

Saltmarshes provide a broad range of high-value ecosystem services and can be sensitive to eutrophication, but elucidating such impacts at broad spatial scales demands a better understanding of the underlying nutrient linkages between saltmarsh soil and tidal waters. We used existing water quality data and field surveys of 15 saltmarshes across a broad trophic gradient of coastal waters, but similar biogeographic setting (in Ireland) to investigate if phosphorus and nitrogen pools in saltmarsh soils are related to those in tidal water across saltmarshes. We also investigated if the strength of such relationships is inversely related to ground elevation, which approximates the degree of tidal inundation. Plant-available phosphorus and nitrogen pools in soil were related to water nutrients, albeit only weakly. We did not find any support for the moderating influence of elevation, indicating that it may be obscured by internal cycling and external sources. We also found evidence for effect of birds on the saltmarsh nutrient pool. Saltmarsh soils are unlikely to serve as general sentinels of nutrient conditions in their corresponding water bodies and may need separate assessment criteria and management tools, which in turn require disentangling localised and whole-saltmarsh sources of variation in nutrient concentrations. [ABSTRACT FROM AUTHOR]

Copyright of Actualidad Jurídica Ambiental is the property of CIEMAT, through its Centro Internacional de Estudios de Derecho Ambiental (CIEDA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Knowledge & Management of Aquatic Ecosystems is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surveys on benthic macroinvertebrate communities of ten standing water bodies (Bezbog, Kalin, Choklyovo marsh, Bistraka, Dospat, Stoykovtsi, Drenov dol, Pchelina, Dolna Dikanya, Dyakovo) were conducted in the period July-August 2018. They were chosen to represent natural (lakes) characterized with reference conditions as well as artificial and heavily modified water bodies (dams). They were associated with earlier data for three dams (Studena, Pyasachnik, Ovchi kladenets), studied over the period 2013-2017. The standing waters fall into the West and East Aegean Basin districts and belong to all types of water bodies (identified according to the Bulgarian typology) located in the Ecoregion 7 (L1-Glacial high-mountain lakes/ Alpine lakes, L3-Mountain lakes, L4-Lowland and semi-mountain lakes and swamps, L6-Riverside wetlands, L11-Large deep reservoirs, L13-Medium-size and small semi-mountain reservoirs, L15 Large lowland reservoirs up to middle depth, L17-Small and medium size reservoirs). A current evaluation based on the values of the measured physicochemical parameters, regulated by the national water legislation was made. Four experimental biological metrics - Total number of taxa, Biotic index for slow-flowing river stretches, percentage of Oligocheata and PETI were applied to assess the ecological status of the studied water bodies. The Biotic index is leading in the evaluation, others metrics have a supportive role. The lack of type-specific scales of the indices used, insufficiently long ranges of data sets on which to test the methods as well as the anthropogenically induced fluctuations at the water level which affects the distribution of macrozoobenthos in the sampling littoral zone are the main difficulties for a more precise assessment of the ecological status/potential of standing water bodies in Bulgaria. [ABSTRACT FROM AUTHOR]