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The article presents the results of a hydrogeological survey aimed to substantiate the engineering recultivation of accumulation ponds of lignin mud by inwashing it with coal ash. The ash bed causes compression consolidation of lignin bed, leading to an increase in the pond seal margin. The mass exchange between the ash and the lignin mud is accompanied by changes in the hydrogeochemical conditions: the mineralization of the liquid phase of technogenic soils increases by a factor of up to 8, and the concentration of microcomplex increases to very high values. The analysis of the qualitative state of groundwater showed it to be tolerant to the effect of accumulation ponds. The moderate deviation from the local natural background is due to other pollution sources. The applied recultivation technology is effective and environmentally safe, though it needs modernization. The alternative technology, proposed by OOO VEB-Inzhiniiring, i.e., grouting the pond content, is extremely hazardous, and the implementation of the project involves considerable environmental risk because of the possible loss of pond containment. [ABSTRACT FROM AUTHOR]

Mediterranean Temporary Ponds (MTPs) are among the most precious habitats in the Mediterranean bioclimatic because they shelter extremely rare and isolated organisms from different taxa and are included in Annex 1 of the Habitat Directive under code 3170*. Nevertheless, their conservation is highly precarious to such an extent to be considered a disappearing ecosystem. To evaluate the perspectives of MTPs in the third millennium, we carried out a literature search, getting on the trail of the string "Mediterranean Temporary Ponds" to answer the following questions: is the focus of these research papers on MTPs sensu Habitat Directive? Do the research areas of investigation mirror the habitat distribution? Which are the main gaps in the issues analysed? Are all the components of the system considered? Our results highlighted the great interest of the scientific community in MTPs. However, it also brought out several problems and knowledge gaps related to the different features analysed: in many cases in which code 3170* is reported, it is just mentioned; the geographical distribution of the studied areas revealed gaps, particularly in the east Mediterranean and throughout the biogeographic regions; among the issues analysed a dearth of research papers related to the identification of the habitat and effects of climate change has emerged; the studies on the biotic components are strongly unbalanced on vascular plants and abiotic components, such as hydrology and water quality, are scarcely investigated. We believe that great efforts should be made to improve practical conservation actions for this habitat in the medium and long term. [ABSTRACT FROM AUTHOR]

The paper is aimed at reconstruction of a source term for external exposure of population that inhabited the banks of the Techa River from 1949 to 1956. The composition of γ-emitting nuclides contributing to radiation environment of the river banks and floodplain is also studied. The γ-emitting nuclides entered the river system both in solutions and as industrial and natural suspended matter. The paper considers archive data on measured parameters of radiation contamination of the Techa bottom sediments and riverside area. Results of the present-day radiation surveys of the Techa River show that the distribution of the exposure dose rate has a pronounced spotted and non-monotonic character along the entire river stretch and is due to sedimentation of suspended particles contaminated with the γ-emitting nuclides on the soil surface. The activity of γ-emitting nuclides accumulated in the upper reaches of the river due to sorption of water-soluble radionuclides onto bottom sediments and to sedimentation of contaminated suspended matter on the surface of bottom sediments was calculated using a stationary sorption model and a hydrodynamic model of settling ponds. Until July 1951, when the river runoff did not exceed 1 m3/s, practically all industrial and natural suspended particles settled to and accumulated at the bottom of Metlinsky Pond. Only a small portion of clay particles could enter the river below the dam of Metlinsky Pond. 95Zr and 95Nb are of high importance for reconstruction of the radiation environment in the Techa riverside area, because before 1953 the activity of the bottom sediments in all segments of the river was predominantly determined by these γ-emitting nuclides. There is practically no sorption of 95Nb onto bottom sediments and suspended matter, and the river flow carries predominantly soluble 95Nb species. 95Zr, on the contrary, is strongly sorbed onto bottom sediments and can be transferred for long distances only as suspended matter or bed silt. Until October 1951, the radiation environment along the entire river stretch below Metlinsky Pond was contributed predominantly by 95Nb and was characterized by uniform and stable contamination level in all swampy areas of the floodplain. Vast contamination of the bottom sediments and the floodplain along the entire river stretch by other γ-emitting nuclides (95Zr, 137Cs, 141,144Ce, 103,106Ru, etc.) could result only from "washing" of Metlinsky Pond in October 1951, when the flow rate in the upper reaches of the river was up to 30 m3/s. This was accompanied by intensive stirring-up of the bottom sediments and activity transfer out of Metlinsky Pond. [ABSTRACT FROM AUTHOR]

The spatially hierarchical stream hydrogeomorphology classification presented by Cox et al. ([3]), based on 42 Irish headwater streams, is simple to apply and may be applicable across northern and western Europe with similar climate - landscape conditions. It is clear from these papers and others presented at SEFS12 that the extensive length of the small stream network and high numbers of ponds poses challenges in terms of water quality and biodiversity monitoring. Small water bodies are increasingly recognised as important for biodiversity and in terms of their influence on downstream water quality and contributions to catchment ecosystem services (Riley et al., [12]). [Extracted from the article]

Monitoring the condition (water quality, biodiversity, hydromorphology) of small water bodies presents a challenge for the relevant authorities in terms of time and resources (labour and financial) due to the extensive length of the stream network or the sheer number of small standing water bodies. Citizen science can help address information gaps, but the effort required should not be underestimated if such projects are to generate reliable and sustained data collection. The overall aim of this paper is to propose a framework for operationalisation of citizen science targeting collection of data from small water bodies. We first consider the data gaps and the elements (water chemistry, ecology, hydromorphology) to be addressed, in order to define where citizen science could best make an impact. We review examples of tools and methods that are appropriate for small water bodies, based on experience from a selection of freshwater citizen science projects, and the support that is needed for effective and sustained small water body projects across Europe. [ABSTRACT FROM AUTHOR]

Regulatory bodies require bioaccumulation evaluation of chemicals within organisms to better assess toxic risks. Toxicokinetic (TK) data are particularly useful in relating the chemical exposure to the accumulation and depuration processes happening within organisms. TK models are used to predict internal concentrations when experimental data are lacking or difficult to access, such as within target tissues. The bioaccumulative property of chemicals is quantified by metrics calculated from TK model parameters after fitting to data collected via bioaccumulation tests. In bioaccumulation tests, internal concentrations of chemicals are measured within organisms at regular time points during accumulation and depuration phases. The time course is captured by TK model parameters thus providing bioaccumulation metrics. But raw TK data remain difficult to access, most often provided within papers as plots. To increase availability of TK data, we developed an innovative database from data extracted in the scientific literature to support TK modelling. Freely available, our database can dynamically evolve thanks to any researcher interested in sharing data to be findable, accessible, interoperable and reusable. Measurement(s) chemical concentration Technology Type(s) High-performance Liquid Chromatography-UV • radioactivity detection • high resolution mass spectrometry Sample Characteristic - Organism Gammarus pulex Sample Characteristic - Environment pond water Sample Characteristic - Location Canton of Zurich [ABSTRACT FROM AUTHOR]

Algal biomass has been gaining attention over the last decades as it is versatile and can be used in different industries, such as wastewater treatment and bioenergy industries. Microalgae are mixotrophic microorganisms that have potential to utilize nitrogen and phosphate (nutrients) and remove organic matters from wastewater streams. Phycoremediation is an intriguing and cost-efficient technique to simultaneously remove heavy metals from wastewater while removing nutrients and organic matters. The cultivated and produced algal biomass can be a promising candidate and a sustainable feedstock to produce biofuels (e.g., biodiesel, bio-alcohol, and bio-oil) and value-added products such as biochar, glycerol, functional food, and pigments. The algae suspended cultivation systems, WSP and HRAP, are efficient methods for the wastewater treatment in shallow ponds with no mechanical aeration and less required energy consumption, but when a short HRT and minimum evaporation losses are key points in the algal cultivation the PBRs are recommended. It was reported that biosorption and bioaccumulation are the two promising techniques of phycoremediation. Studies showed that among the current processes of algal biomass conversion to biofuels, transesterification of algal lipids and pyrolysis of algal biomass were found to be the most efficient techniques. This review paper investigates the applications of algal biomass in the phycoremediation of wastewater, productions of bioenergy and value-added products by reviewing articles mainly published over the last five years. [ABSTRACT FROM AUTHOR]

Dams are hydraulic infrastructure that have several purposes, such as irrigation, hydropower, water supply, flood control, recreation, fish breeding and navigation. However, their failure or malfunctioning can pose a threat to downstream communities, and thus, their safety is paramount to public protection and economic security. A variety of approaches to classify dams can be found in countries worldwide. Their classification allows to distinguish among those that are to be subject to safety regulation in each country. A common approach to classify them is according to their potential damage in case of failure. Roads are usually among the infrastructures that these approaches consider to be assessed in terms of the level of damage that can suffer. A new people-centred criterion is proposed in this paper to assess potential intangible damage (i.e. human lives) when roadways could be flooded due to a dam failure. This novel methodology is based on the Average Daily Traffic (ADT) of roadways and sets a maximum and a minimum number of vehicles expected in the area receiving the flood. To evaluate its appropriateness, it is verified from the results obtained after being applied to three existing ponds located in Catalonia (Spain). [ABSTRACT FROM AUTHOR]

Urban surfaces are often covered by impermeable materials such as concrete and asphalt which intensify urban runoff and pollutant concentration during storm events, and lead to the deterioration of the quality of surrounding water bodies. Detention ponds are used in urban stormwater management, providing two-fold benefits: flood risk reduction and pollution load minimization. This paper investigates the performance of nine proposed detention ponds (across the city of Renton, Washington, USA) under different climate change scenarios. First, a statistical model was developed to estimate the pollutant load for the current and future periods and to understand the effects of increased rainfall on stormwater runoff and pollutant loads. The Personal Computer Storm Water Management Model (PCSWMM) platform is employed to calibrate an urban drainage model for quantifying stormwater runoff and corresponding pollutant loads. The calibrated model was used to investigate the performance of the proposed nine (9) detention ponds under future climate scenarios of 100-year design storms, leading to identifying if they are likely to reduce stormwater discharge and pollutant loads. Results indicated significant increases in stormwater pollutants due to increases in rainfall from 2023 to 2050 compared to the historical period 2000–2014. We found that the performance of the proposed detention ponds in reducing stormwater pollutants varied depending on the size and location of the detention ponds. Simulations for the future indicated that the selected detention ponds are likely to reduce the concentrations (loads) of different water quality constituents such as ammonia (NH3), nitrogen dioxide (NO2), nitrate (NO3), total phosphate (TP), and suspended solids (SS) ranging from 18 to 86%, 35–70%, 36–65%, 26–91%, and 34–81%, respectively. The study concluded that detention ponds can be used as a reliable solution for reducing stormwater flows and pollutant loads under a warmer future climate and an effective adaptation option to combat climate change related challenges in urban stormwater management. [ABSTRACT FROM AUTHOR]

Combining environmental isotope analysis with principal component analysis can be an effective method to discriminate the inflows and sources of contamination in mining-affected watersheds. This paper presents a field-scale study conducted at an acid mine drainage (AMD)-contaminated site adjacent to a pyrite mine in South China. Samples of surface water and groundwater were collected to investigate transport in the vadose zone using stable isotopes of oxygen (δ18O) and hydrogen (δD) as environmental tracers. Principal component analysis of hydrogeochemical data was used to identify the probable sources of heavy metals in the AMD. The heavy metal pollution index (HPI) was applied to evaluate the pollution status of heavy metals in the groundwater. The groundwater associated with the Datai reservoir was recharged by atmospheric precipitation and surface water. On the side near the AMD pond, the groundwater was significantly affected by the soluble metals produced by pyrite oxidation. The concentrations of some metals (Al, Mn, and Pb) in all of the samples exceed the desirable limits prescribed by the World Health Organization (Guidelines for drinking-water quality, 4th edn. World Health Organization, Geneva, 2011). Among them, the concentration of Al is more than 30,000 times higher than the desirable limits prescribed by the World Health Organization (2011), and the concentration of Mn is more than 3000 times higher. The HPI values based on these heavy metal concentrations were found to be 10–1000 times higher than the critical pollution index value of 100. These findings provide a reference and guidance for research on the migration and evolution of heavy metals in vadose zone water in AMD-contaminated areas. [ABSTRACT FROM AUTHOR]

Increasing demand for fishes has necessitated boosting aquaculture production worldwide. Development of aquaculture system is possible by using manmade devices called aerators. Aerators have been used over the years which are typically installed in ponds to facilitate water movement also help to supply sufficient dissolved oxygen (DO). The main point of concern is selecting a suitable aerator in optimizing the benefits with less operational cost of aeration. The aim of this paper is the economic evaluation of the proposed venturi aerator (VA) with different existing aerators, i.e., 1HP 4 paddle wheel aerator (PWA), 2HP 4 submersible venturi jet aerator (SVJA1), 1HP submersible venturi jet aerator (SVJA2), and aspirating aerator (AA) for different pond volumes, different initial DO concentration values of pond, and varying operating hours of aerators. To find out the suitability of an aerator, analysis is based on the aeration cost assessment per unit time of operational hours. It was found that the proposed VA has a meagre aeration cost as compared to other aerators for initial DO concentration of pond when considering the low volumes of pond. Thus, the VA can be considered efficient to meet the aeration demand in an aquaculture system. [ABSTRACT FROM AUTHOR]

Healthy pond ecosystems are critical for achieving several sustainable development goals (SDG) through numerous ecosystem services (e.g., flood control, nutrient retention, and carbon sequestration). However, the socio-economic and ecological value of ponds is often underestimated compared to the larger water bodies. Ponds are highly vulnerable to mounting land-use pressures (e.g., urban expansion, and agriculture intensification) and environmental changes, leading to degradation and loss of the pond ecosystem. The narrow utilitarian use-based conservation fails to recognize the multiple anthropogenic pressures and provides narrow solutions which are inefficient to regenerate the degraded pond ecosystem. In this paper, we holistically examined the legal challenges (policies) and key anthropogenic and environmental pressures responsible for pond degradation in India. The country is strongly dedicated to attaining SDG and circular economy (CE) through aquatic ecosystem conservation and restoration. Considerable efforts are required at the administration level to recognize the contribution of pond ecosystem services in attaining global environmental goals and targets. Worldwide restoration strategies were reviewed, and a framework for pond restoration and conservation was proposed, which includes policies and incentives, technologies such as environmental-DNA (e-DNA), life cycle assessment (LCA), and other ecohydrological measures. Nature-based solutions (NBS) offer a sustainable and cost-effective approach to restoring the pond’s natural processes. Furthermore, linkage between the pond ecosystem and the CE was assessed to encourage a regenerative system for biodiversity conservation. This study informs the need for extensive actions and legislative reforms to restore and conserve the pond ecosystems. [ABSTRACT FROM AUTHOR]

Stormwater ponds are widely used for controlling runoff quality through the sedimentation of particles and associated pollutants. Their maintenance requires regular removal and disposal of accumulated material. This necessitates an assessment of material hazardousness, including potential hazard due to its contamination by metals. Here we analyze 32 stormwater pond sediment samples from 17 facilities using several chemical analysis methods (total extraction, sequential extraction, diffusive gradients in thin-films DGT, and pore water extraction) in order to consider the complementarity and comparability of the different approaches. No clear relationship was found between analyses that have the potential to measure similar metal fractions (DGT and either fraction 1 of the sequential extraction (adsorbed and exchangeable metals and carbonates) or pore water concentrations). Loss on ignition (LOI) had a significant positive correlation with an indicator of the environmental risk developed in this paper (∑ranks) that incorporates different metals, speciations, and environmental endpoints. Large variations in metal levels were observed between ponds. As clustering was limited between the different analyses, a comprehensive analysis of different parameters is still needed to fully understand metal speciation and bioavailability. [ABSTRACT FROM AUTHOR]

The constant dynamic changes in salt pond make it difficult to achieve accurate prediction of ion concentration. It is of great significance to get the accurate prediction of potassium ion concentration in salt pools for the actual production of potash fertilizer. In this paper, some machine learning methods, such as support vector regression (SVR), AdaBoost regressor, K neighbor regressor, gradient boosting regressor, extra trees regressor and neural network regressor, have been used to build the prediction models. In the experiment, the MSE and R2 of the K+ concentration by using SVR in test data set reach 0.26385 and 0.9414, which are better than other models. Therefore, the SVR model has high research value in the field of salt pool ion concentration prediction. [ABSTRACT FROM AUTHOR]

In this paper, a multi-objective decision model is formulated utilizing both single-layer and three-layer radon reduction layer materials by considering radon emanation rate and cost as decision objectives. Through a multi-objective non-dominated ranking method, the optimal solution is identified from a range of feasible alternatives. In the case of the example uranium tailings pond, the optimized three-layer radon reduction layer materials reduce the comprehensive cost by 47.8% compared with the single-layer radon reduction layer materials while meeting the radon emanation rate limit. Furthermore, the utilization of non-dominated multi-objective optimization techniques demonstrates higher efficiency in optimizing each radon reduction layer schemes. [ABSTRACT FROM AUTHOR]

Specified class II nationally rare species of wild fauna/flora designations were first made in Japan for three species, the Tokyo salamander (Hynobius tokyoensis), golden venus chub (Hemigrammocypris rasborella), and giant water bug (Kirkaldyia deyrolli). These species depend on the shallow water in agroecosystems, secondary forests, and parks. The objective of this paper was to provide an overview of the factors relating to their conservation, which were as follows: (1) the landscape affects significantly on distributions of three species. H. tokyoensis and K. deyrolli both require landscapes in which wetlands and forests connect. While H. rasborella inhabits isolated ponds also, the original habitat is a flood plain where fishes seasonally move temporary pools for spawning. Therefore, channel networks are needed to protect fishes including H. rasborella. (2) Agricultural land infrastructure affects the three species, as dry paddy fields and concrete-lined ditches are unsuitable for them, as well as other aquatic animals. Several construction methods, however, have been trialed to allow fish to live in modernized ditches. (3) K. deyrolli is highly sensitive to pesticides. (4) Mid-summer drainage of paddy fields will threaten populations of H. tokyoensis and K. deyrolli as these paddy fields lose water before these species have completed their metamorphosis. Wet-paddy fields that are not completely dried, postponement of mid-summer drainage, and the installation of diversion ditches, however, could all help to mitigate this issue. (5) The impacts of abandoned cultivation and pond management are significant for these species. (6) Invasive alien species have a significant impact on H. tokyoensis and H. rasborella. (7) Habitat creation and translocation of these species has often been successful. However, the sustainability of the translocated populations is a challenge. When these species are introduced outside their natural habitats, it is thus necessary to consider the ecosystem of the destination area and the genetic background of the target species. I conclude that the combination of biotopes with wildlife-friendly farming and continuity of paddy fields with forests throughout the landscape secure the population sustainability. [ABSTRACT FROM AUTHOR]

Ponds are often identified by their small size and shallow depths, but the lack of a universal evidence-based definition hampers science and weakens legal protection. Here, we compile existing pond definitions, compare ecosystem metrics (e.g., metabolism, nutrient concentrations, and gas fluxes) among ponds, wetlands, and lakes, and propose an evidence-based pond definition. Compiled definitions often mentioned surface area and depth, but were largely qualitative and variable. Government legislation rarely defined ponds, despite commonly using the term. Ponds, as defined in published studies, varied in origin and hydroperiod and were often distinct from lakes and wetlands in water chemistry. We also compared how ecosystem metrics related to three variables often seen in waterbody definitions: waterbody size, maximum depth, and emergent vegetation cover. Most ecosystem metrics (e.g., water chemistry, gas fluxes, and metabolism) exhibited nonlinear relationships with these variables, with average threshold changes at 3.7 ± 1.8 ha (median: 1.5 ha) in surface area, 5.8 ± 2.5 m (median: 5.2 m) in depth, and 13.4 ± 6.3% (median: 8.2%) emergent vegetation cover. We use this evidence and prior definitions to define ponds as waterbodies that are small (< 5 ha), shallow (< 5 m), with < 30% emergent vegetation and we highlight areas for further study near these boundaries. This definition will inform the science, policy, and management of globally abundant and ecologically significant pond ecosystems. [ABSTRACT FROM AUTHOR]

Disease outbreaks have been seen as the major threat to sustainable aquaculture worldwide. Injectable vaccines have been one of the few strategies available to control the diseases, however, the adoption of this technology globally is limited. Genetic selection for disease resistance has been proposed as the alternative strategy in livestock and aquaculture. Economic analysis for such strategies is lacking and this study assesses the economic worth of using tilapia fingerlings resistant to Streptococcosis in both cage and pond production systems. The paper also assesses the profitability of paying the higher price for such fingerlings. Partial-budgeting was used to develop a stochastic simulation model that considers the benefits and costs associated with the adoption of tilapia fingerlings resistant to Streptococcosis at the farm level, in one production cycle. In both ponds and cage production systems, the use of genetically selected Streptococcus resistant tilapia fingerlings was found to be profitable where Streptococcus infection is prevalent. In the cages and ponds where Streptococcus related mortality was ≥ 10%, the Nile tilapia aquaculture was found to be profitable even if the amount paid for genetically selected Streptococcus resistant tilapia fingerlings was 100% higher than the amount paid for standard fingerlings. [ABSTRACT FROM AUTHOR]

In species with complex life cycles, such as anuran amphibians, several traits are influenced by ecological factors during ontogeny. The anuran Physalaemus nattereri shows an aquatic spawning behavior, placing foam nests at the edges of a pond where the water contacts land, exposing tadpoles to dehydration once the pond dries. P. nattereri tadpoles are known to present an intermediate ability to survive out of water when compared to other species reproducing in permanent or temporary ponds. A decrease in size of tadpole tails has been suggested to represent a response to cope with dehydration stress, but might impair swimming performance. We investigated the effect of dehydration on morphological traits, focusing especially on tail proportions, as well as burst swimming speed. P. nattereri tadpoles were exposed to hydric stress on moist paper substrates and morphology and locomotor performance was compared within the same individuals before and after hydric stress. Our experiment showed that morphological changes induced by hydric stress were directly related to swimming performance. Individuals having smaller tails, due primarily to contractions of the medial to distal tail portions, exhibited reduced times to reach burst speed and reduced burst speeds. [ABSTRACT FROM AUTHOR]

The article attempts to define and determine the intangible components of cultural heritage related to the spatial structure of land in a comprehensive way using computational methods. The components were quantified and a method of empirical evaluation of landscape durability was proposed for agricultural areas of significant cultural and historical value with an evident mosaic structure of fields, baulks, ponds, meadows, and forests. This method allows us to identify places more resistant to political transformation and those with greater cultural potential. The paper proposed an integrated approach to the measuring of the degree of preservation of spatial arrangements in the landscape based on a set of objects that describe the spatial land structure. The article classifies areas by the degree of preservation of rural spatial arrangements of land. The spatial analysis employed facilitated a synthetic quantification of the multi-criteria process. Three groups of factors were used: spatial assessment of land-cover type persistence (u), agricultural land structure persistence (w), and persistence of settlement buildings (z). The final results pinpointed areas in need of strategic intervention to sufficiently protect the rural cultural heritage, properly consider them in zoning planning, and ensure their sustainable development. The proposed tool can be used to monitor the degree of changes in the landscape layout structure when multiple time points are analysed as well. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD) is a serious and persistent environmental pollution problem. At present, many studies have focused on the tailings pond's cover systems. This paper introduced the research results of using tin tailings from Laili mountain to make the covering layer of tailings pond. The first part included a detailed description of tailings characterization and acid production potential. On this basis, the hard layer (HL) was prepared and its feasibility as oxidation barrier was evaluated. It was found that when the proportion of tailings waste was 70%, the immobilization efficiency of heavy metals can reach more than 99.45%, and the pH of leaching solution was about 10.8. Moreover, the beneficial effect of solid waste addition on the HL was also verified. This suggests that HL as a post-mining restorative strategy has strong positive influence on pollution control. [ABSTRACT FROM AUTHOR]

Creep properties of altered granite were changed due to water level rise and fall in the tailings ponds. In this paper, the effects of water influx-lost cycles on the creep properties were tested. The axial load was applied with the 30%, 40%, 60%, 75% and 100% of the triaxial compressive strength, the rock creep test results showed that: (1) Significant creep effects of altered granite subjected to water influx-lost cycles, the creep stages were included decay creep stage, steady creep stage, and accelerated creep stage. It was found that the creep strain gradually increases with of the number of water influx-lost cycles increases, and the ratio of the maximum creep strain to total strain can reach 10.42%. (2) The degradation of long-term strength of altered granite subjected to water influx-lost cycles was studied, the long-term strength was decreased from 32.13 to 5.46 MPa. The relationship between the long-term strength and number of cycles was indicated by an exponential function. It was found that water influx-lost cycles have adversely effects on the long-term stability of the tailing pond slope, and the research results are of great significance to the prevention of slope engineering disasters. [ABSTRACT FROM AUTHOR]

The paper is concerned with the results of 137Cs monitoring in the irrigation ponds of the Okuma town in the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) exclusion zone. The 137Cs activity concentrations in the ponds appeared to be higher than those in the rivers and dam reservoirs in the region. The study has revealed a trend for a decline in 137Cs activity concentrations, both particulate and dissolved. The rate of particulate 137Cs decline was much higher than that of dissolved. The total distribution coefficient ) in the suspended sediment–water system in the studied ponds was decreasing in time with the rate constant of 0.12–0.18 year–1. Assuming that the decrease in is associated with decomposition of hot glassy particles, the time scale of 137Cs leaching from them in these water bodies was estimated to be 5–8 years. These estimates are consistent with the findings of recent laboratory experiments on the subject. With respect to seasonal variations, the highest levels of dissolved 137Cs in the studied ponds were observed from June to October as a function of specific pond and monitoring year. Based on data about 137Cs speciation in the bottom sediment top layer of the ponds and its distribution in the sediment–water system, the exchangeable radiocesium interception potential for the ponds sediments was estimated to be 1650–2250 mg-eq/kg, which is within the range of values measured by laboratory studies. [ABSTRACT FROM AUTHOR]

The paper focuses on the effect of ponds (geographically isolated wetlands) on water quality within internally drained areas in a river catchment. The important part of the study was the point of formation of a periodic hydrographic network of internally drained areas linked with a main river as well as the identification of the circulation pattern of ions in such a system. The aim of the study was to examine the extent to which ponds pollute the main river upon physical connection with it. Research has shown that ponds participate actively in material circulation—including that of water and biogenic ions. The hydrographic network in Young Glacial areas is subject to very large seasonal changes. In the study area, the total length of the stream network in the dry season equaled 12 km, while in the wet season almost 75 km. At the same time, almost 50% of the internally drained areas in the catchment became connected with the surface runoff network. Such large seasonal changes in the hydrographic network yield large changes in stream water chemistry. In the study area, only 6 ponds were linked to the stream network during the dry season, while in the wet season, this number increased to 125. The parts of catchments featuring the largest changes in the hydrographic network as well as the largest number of ponds temporarily linked with surface runoff networks were characterized by a high content of total nitrogen and phosphorus—up to 244.2 kg N km2 per month and 26.2 kg P km2 per month. [ABSTRACT FROM AUTHOR]

In Europe, ponds are an exceptionally numerous and widely distributed landscape feature forming a major part of the continental freshwater resource and contributing significantly to freshwater biodiversity conservation. This has been reflected by a growing scientific concern over the first few years of the twenty-first century and is evidenced by an increasing number of academic publications on pond related topics, particularly those relating to biodiversity. It is essential, however, that this expanding scientific knowledge is widely disseminated to those involved with pond management and is then rapidly translated into action. Inevitably, the task of transferring science to practice remains a significant challenge. As a first step towards meeting this challenge the European Pond Conservation Network (EPCN), at its biennial meeting in 2008 in Valencia (Spain), made this the main theme of the conference together with two special workshops further encouraging exchanges between scientists, practitioners and policy makers. The papers selected for this special issue of Hydrobiologia (from over 120 communications presented) are all from the conference. They represent a diverse collection of themes from across the continent and North Africa and present new and original insights into topics as wide ranging as: pond biodiversity; human disturbance; landscape ecology; ecological assessment and monitoring; practical management measures; ecological restoration; hydrology and climate change; invasive species and threatened species. In all cases, the papers demonstrate an overriding need for the development of a tight link between scientific knowledge and management. Furthermore, scientific advances have to be beneficial for on the ground management and, vitally, have to be disseminated, communicated and implemented into local, national and international policy. As such, national and international networks (such as the EPCN) have a central role to play and have to develop a robust information and communication strategy which will enable the dissemination of best practice materials and advice across the continent and beyond. The work contained in this volume represents a step in the right direction and will help to ensure that ponds remain a characteristic and highly visible feature of the European landscape in the twenty-first century. [ABSTRACT FROM AUTHOR]

This paper investigates the capability of adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) modeling approach to predict the unconfined compressive strength (UCS) of stabilized pond ashes with lime alone and in combination with lime sludge. Out of 170 data set, a total of 119 data were randomly selected for training, whereas remaining 51 were used for testing the model. Four membership's functions (MFs) such as Gaussian, generalized bell-shaped, triangular, and trapezoidal were used with ANFIS model. Statistical parameters were used to compare the performance of four MF-based ANFIS and ANN models. A comparison of results suggests that Triangular MF-based ANFIS model exhibit better predictive performance with higher CC = 0.980 and lower MSE = 3028.515 and RMSE = 55.032 than other MF-based ANFIS and ANN model. The results of single-factor analysis of variance indicate that there is an insignificant difference between measured and predicted values of UCS using different models. Further, results of sensitivity analysis depict that the curing period, lime sludge, and lime are the most important parameters which affect the performance of Triangular MF-based ANFIS in predicting the UCS of stabilized pond ashes. Thus, the Triangular MF-based ANFIS model could be a useful tool in predicting the UCS value of stabilized pond ashes because of its adequacy in handling uncertainties in the test results with accuracy. [ABSTRACT FROM AUTHOR]

Groundwater resources are depleting at an alarming rate all over the world. Therefore, ensuring water security is the foremost priority of every nation. This paper presents a simple methodology to estimate groundwater recharge from rural ponds and to study the impact of climate change and urbanization on the recharge potential. It was found that built-up in the study area has increased by 51% since 2002 as a consequent of which, the total area occupied by ponds has decreased by 11%. This has resulted in a decrease in the recharge volume from these ponds by 14.74%. Thus, there is an urgent need to rejuvenate and maintain natural ponds and lakes, which is much more economical than constructing artificial percolation tanks and injection wells as discussed in the report. This study will also help various Government initiatives of rejuvenation of natural ponds and lakes in identifying those ponds which need to be revived based on their size, amount of surface runoff stored by the ponds and the volume of groundwater recharge through seepage from the bed of ponds. [ABSTRACT FROM AUTHOR]

This paper presents a case study on the impact of dynamic management of wetland storage on downstream flood control at the Cypress Creek Watershed in Houston, Texas. Dynamic storage management is performed by optimizing the schedule of flow releases from managed wetlands for minimizing downstream inundation. The novelty of this study is to increase the available storage capacity of wetlands on a watershed scale and thus improve their performance on flood mitigation. The main objective of this study is to compare the extent of downstream flood inundation with and without dynamic management of wetland storage. This study used HEC-HMS for the overland flows and the level pool routing in the wetlands and HEC-RAS for simulating river inundation. Wetlands were implemented in the midstream region of the watershed. The schedule of optimal wetland flow releases were determined using the MATLAB Genetic Algorithm toolbox. The optimization results indicate that, when wetland size exceeds a fairly low threshold, dynamic storage management of wetlands can significantly reduce flood area, flood depth and flood duration at the downstream region of the watershed compared with the case without dynamic storage management. [ABSTRACT FROM AUTHOR]

Stormwater ponds manage urban runoff and mitigate storm-event flooding. Stormwater ponds also offer various secondary advantages such as filtering pollutants, providing a habitat for wildlife, and adding recreational value and access to green spaces to communities. However, stormwater pond features and their potential to offer secondary benefits can vary based on the initial construction and the ongoing maintenance practices. This study developed an assessment tool for evaluating stormwater ponds' expected functioning for secondary benefits, including potential for pollutant filtering by shoreline vegetation, safety, and access by people for activities like walking or wildlife viewing. We used the tool to compare stormwater ponds in East Tampa and Riverview, Florida, communities with contrasting socioeconomic backgrounds. The overall pond functioning was consistent between both communities; however, several distinctions emerged between specific pond attributes. Suburban ponds exhibited narrower buffer zones, lower bank stability, and less lighting. Conversely, ponds in the lower-income East Tampa had lower accessibility due to a higher number of fences, more litter, and inferior water appearance. This study uncovered a need for consideration of stormwater pond secondary benefits in both communities and an untapped potential to transform stormwater ponds into vibrant green spaces. Highlights: Stormwater ponds offer secondary ecological and social benefits, varying by initial construction and upkeep practices. Differences in pond features were noted between inner-city and suburban communities, indicating areas for improvement. There is potential to enhance stormwater ponds as green spaces in all communities, irrespective of socioeconomic status. [ABSTRACT FROM AUTHOR]

This study aims to analyze survival rates in milkfish modular cultivation systems and their correlation with fluctuations in temperature and salt content. The modular system method was used, with three plots: plot A as the nursery plot, plot B as the first rearing plot, and plot C as the enlargement plot 2. The research was conducted over 1 year with three maintenance cycles, each cycle lasting 4 months. The organisms were placed in plot A for a period of 1–8 months. Thus, in 1 year, plot A gets the opportunity to rest for 4 months while preparing, then in grow-out plot 1 and grow-out plot 2 for 2 months each, so that each grow-out plot gets the opportunity to rest while preparing for the next maintenance cycle. Results revealed that the temperature, salt content, pH, and dissolved oxygen were within the optimal range, with an average value of 29.4 °C, pH of 6.9, and dissolved oxygen of 31 ppm. However, the salt content fluctuated a lot, with values ranging between 5 and 45 ppt with an average value of 26.9 ppm. The average survival rate was 91% with a correlation of R2 = 0.906 (cycle 1), 95% with a correlation of R2 = 0.890 (cycle 2), and 97% with a correlation of R2 = 0.997 (cycle 3). To conclude, the modular cultivation system, apart from increasing survival rates, can also improve the pond soil environment. This system is highly suitable as a promising approach for sustainable fisheries development in the region. [ABSTRACT FROM AUTHOR]

Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries. [ABSTRACT FROM AUTHOR]

Freshwater invertebrates and zooplankton (FIZ) play a key role in freshwater ecosystems and in food webs, but there is little research on their life cycle, ecology, and conservation. Therefore, this study focused on FIZ' annual dynamics (abundance, diversity, and gross energy) in 30 ponds located in two wetlands: the Marais breton and Marais poitevin (Atlantic coast, France, Europe). These ponds had a FIZ abundance of 50,412 ind/m3 per site [range of 28,864–80,690] in a year. The study defined four typologies of ponds according to the environmental variables and the presence of some key FIZ taxa. The first group had a long flooding time, high silt content, and aquatic vegetation cover. The associated taxa were Chironomidae, Gammaridae and Atyidae. The second group of ponds had moderate slopes, high sand content in the sediment and a rich abundance of microcrustacea. The third group contained shallow ponds with soft slopes and a high aquatic vegetation cover (100%), which result in high FIZ diversity. Finally, the fourth group contained ponds with steep slopes, high silt content in the sediment, and Oligochaeta as the major taxon in this environment. Defining pond typologies based on environmental factors and FIZ is essential to adapting FIZ management and conservation measures implemented on ponds. In a context of global change, a reduction or even disappearance of FIZ communities would have a catastrophic impact on all faunal taxa dependent on FIZ as a food resource. [ABSTRACT FROM AUTHOR]

Computational models often are applied to simulate water quality for management of natural and constructed aquatic systems. As part of a larger study, a three-dimensional hydrodynamic and biogeochemical model was applied to three storm-water ponds in the City of Edmonton to examine relations between nutrients and eutrophication. This paper reports on the calibration and validation procedure of the hydrodynamic component of the model suite. It was found that correcting surface heat fluxes for atmospheric instability (defined as the difference between air and water temperature) led to greater latent and sensible heat loss (up to ~ 32% and ~ 34%, respectively) and resulted in the most accurate simulation of observed temperature time series (root-mean-square error, RMSE < 3.03 °C). The calibration also involved tuning of albedo and light attenuation coefficients, which were optimized by applying a global sensitivity analysis tool that showed the model was more sensitive to albedo. Global sensitivity analysis, can be applied to develop a resulting limited area, which is shown to be a valuable tool to optimize the calibration process. [ABSTRACT FROM AUTHOR]

Background: This study examines seasonal and regional trends in chlorophyll-a concentrations and the dynamics of nitrogen (N) and phosphorus (P) in 32 fishponds (resulting in 150 pond-year cases) employed for fish production. Fishponds have a poor ecological state, requiring further insights for pond management. To gain those insights, monthly data on the pond environment were collected over the growing seasons from April to September (up to 14 years) across lowland to highland regions in Czechia. We used a ratio of dissolved inorganic nitrogen to total phosphorus (DIN:TP) to investigate seasonal patterns of N and P limitations. Results: Fishponds in the lowland region (below 199 m above sea level, a.s.l.) were predominantly N-limited (80%), while ponds in the midland region (200–449 m a.s.l.) exhibited P limitation at the beginning of the growing season (April–May) and N limitation by the end of the season (August–September; 90% of fishponds). Highland fishponds (above 450 m a.s.l.) showed frequent P limitations, especially during the beginning of the season. Chlorophyll-a concentrations varied on both regional and seasonal scales, with the overall phytoplankton biomass peak at 31 ha of pond surface area. Chlorophyll-a remained stable at the beginning of the season regardless of the DIN:TP ratio but increased with a lower DIN:TP ratio by its end. The chlorophyll-a concentrations were lowest at the beginning and highest at the end of the season and decreased with altitude. Conclusions: Seasonal and regional variations in nutrient limitations and chlorophyll-a occur in fishponds. Our study suggests that targeted seasonal nutrient input and enhanced monitoring can significantly improve fishpond management practices and ecosystem stability. [ABSTRACT FROM AUTHOR]

The Gore Glen pond is located in the forested floodplain of the Gore River, in the Mid-Lothian region near Edinburgh, Scotland. This work has considered in detail the hydrology, hydrochemistry, and biodiversity of the pond together with all their interactions and in addition interactions with the adjacent Gore River. It is important as it is one of few studies considering all these issues for a pond located in a riverine floodplain. This work shows the pond is connected to the Gore River for discharge events in the river larger than a 1 in 5-year return period. For these events, the pond acts as an online storage feature and will attenuate the flow, thus contributing towards the mitigation of downstream flooding. These large events are also a potential source of the large amount of sediments, as well as adsorbed chemicals, accumulated in the pond. The open water surface of the pond is covered by duckweed, Lemna minor, for most of the year, and that has profound implications for the hydrobiological community and biogeochemical cycling. The system is characterised by nutrient release from sediments due to the extensive hypolimnion anoxia in the summer/autumn period caused by the decomposition of organic matter. Algae are mostly represented by epiphytic diatoms and the cyanobacterium Microcystis, but their development appears to be constrained by light penetration. The eutrophic conditions are also conducive for the population of Difflugia (Protozoa, Rhizopoda). This work improves our understanding of the ecological relations of testate amoebae—an important group which has recently been used as biological indicators for the analysis of paleoecological relationships and paleogeographical reconstructions. [ABSTRACT FROM AUTHOR]

During the opening session of ICCE 2019, Professor emeritus Panagiotis Siskos, University of Athens, Greece, received the DCE Lifetime Achievement Award for his early and long-lasting contributions to environmental chemistry studies in the Mediterranean region and particularly in Greece and his services for the Division of Chemistry and Environment of the European Chemical Society. The 17th International Conference on Chemistry and the Environment (ICCE 2019) took place in the period 16-20 June 2019, in Thessaloniki, Greece. The ICCE has been organized since 1980 by the Division of Chemistry and the Environment (DCE) of the European Chemical Society (EuChemS) as a biennial conference. [Extracted from the article]

Polyculture of black tiger shrimp Penaeus monodon, mud crab Scylla paramamosain, and red seaweed Gracilaria tenuistipitata, were applied in improved extensive ponds in the Vietnamese Mekong delta to evaluate production and financial efficiency. The trial consisted of two treatments: (1) non-feed supplement, in which shrimp consumed only natural food in the culture pond; and (2) feed supplement, in which shrimp received commercial feed (50% feeding rate). Treatments were in triplicate; ponds featured natural occurrence of red seaweed. Postlarvae of shrimp and crab were stocked at densities of 4 ind./m2 and 0.15 ind./m2, respectively, and culture for six months. Results showed that shrimp receiving feed supplement demonstrated much better (P < 0.05) growth and survival than those without feed supplementation. Shrimp yield was significantly higher (P > 0.05) in the feed supplement pond (348.9 kg/ha) than in the non-feed supplement pond (169.2 kg/ha). Crab production was similar between the two treatments (P > 0.05), varying from 88.1 to 92.4 kg/ha. Production cost (456.2 US$/ha) in the non-feed supplement pond was significantly lower than that in the feed supplement pond (944.8 US$/ha), but the former produced less profit (2,230.9 US$/ha) than the latter (4,169.2 US$/ha). Notably, the average benefit–cost ratio in the non-feed supplement group (4.84 times) was relatively higher compared to the feed supplement group (4.35 times). These findings suggest that polyculture of shrimp, crab, and seaweed in the improved extensive pond could be applied either non-feed supplement or feed supplement for shrimp, depending on the financial conditions of the farmers. [ABSTRACT FROM AUTHOR]

The present study investigated the integration of halophytes in IMTA as extractive species on the water quality, growth, digestive, and antioxidant activity of Penaeus monodon and Chanos chanos in earthen ponds for 120 days. The experimental setup consisted of three treatments: control (C) and two different halophyte-based IMTA treatments, T1 and T2, randomly assigned to nine earthen ponds (200 m−2) in three replicates. All treatments were uniformly stocked with P. monodon (Post larve 12) and C. chanos (13.4–14 g); in addition to these, T1 had Avicennia officinalis and Meretrix casta and T2 had Bruguiera gymnorhiza and Meretrix casta as extractive species. The average final body weights of P. monodon (32.01 ± 0.27 g) and C. chanos (94.18 ± 1 g) were found in the A. officinalis based IMTA treatment (T1). T1 also had shown a significant (p < 0.05) reductions in total ammonia nitrogen (97.5%), nitrite-N (NO2-N) (56.1%), and nitrate (NO3-N) (41.1%). Biological oxygen demand (BOD) (3.17 ± 0.15 ppm), chemical oxygen demand (COD) (25 ± 0.58 mg L−1), and total suspended solids (TSS) (20 ± 1.15 mg L−1) were significantly (P < 0.05) lower in T1. Digestive enzyme activity in shrimp and fish was higher in T1 and T2. A decrease in catalase and SOD enzyme activities was observed in T1 and T2. Halophyte-and M. casta-based IMTA treatments (T1 and T2) showed a decrease in the total Vibrio and heterotrophic bacterial counts. The present research findings elucidated that halophytes as extractive species can be beneficial in brackishwater IMTA systems to maintain water quality, improve the health status of cultivated organisms, and increase aquaculture productivity. [ABSTRACT FROM AUTHOR]

Urbanisation is one of the greatest threats to freshwater biodiversity, with the area of land covered by towns and cities predicted to increase significantly in the future. Ponds are common features in the urban landscape and have been created for a variety of reasons ranging from ornamental/amenity purposes through to the detention of urban runoff and pollution. This paper aims to quantify the aquatic macroinvertebrate biodiversity associated with garden, ornamental and other urban ponds in Leicestershire, UK. We examined the macroinvertebrate biodiversity of 41 urban ponds (13 garden, 12 park and 16 other urban ponds) within the town of Loughborough, UK. Park ponds supported greater macroinvertebrate richness than garden or other urban ponds. Garden ponds were the most taxon poor. Pond size was strongly correlated with macroinvertebrate diversity. Collectively, urban ponds were found to be physically and biologically heterogeneous and were characterised by high community dissimilarity. Urban ponds provide a diverse range of habitats for a mixture of common and rare aquatic macroinvertebrate taxa and represent a valuable biodiversity resource within anthropogenically dominated landscapes. Recognition of the significant contribution of ponds to urban freshwater biodiversity is important for future aquatic conservation within anthropogenically dominated landscapes. [ABSTRACT FROM AUTHOR]

This paper discusses four challenges for mainstreaming climate change into European flood and drought risk management policies within the water and agriculture sectors: the climate change impact challenge; the robust policy challenge; the EU policy maze challenge; and the implementation challenge. We illustrate with examples from the Warta River Basin in Poland. The challenge of reliably estimating the impact of climate change on flood and drought risk at the local and regional scales has led to the pursuit of robust policy solutions. Robust policy solutions, as we demonstrate by comparing reservoirs and small ponds, can be equally intractable given the lack of information on their costs, benefits, and co-benefits, particularly if climate change is taken into account. The mainstreaming challenge is further complicated by the myriad of EU policies targeting flood and drought risks. While the European Commission is working towards a coherent policy picture, we demonstrate contradictions regarding reservoir and other water retention policies. Finally, mainstreaming climate change in flood and drought policy is further challenged by the web of responsible institutions at local, regional, and national scales. [ABSTRACT FROM AUTHOR]

In contrast to pelagic and benthic realms of the aquatic ecosystems, studies on the metaphytic habitats remain underrepresented in the literature. However, this realm may have a potential impact on composition and diversity of the open water assemblages through metacommunity processes (source-sink dynamics, mass-effect) especially in small ponds with extended littoral zone. Using a limnocorral experiment we studied how metaphyton affects diversity and composition of open water phytoplankton in a small eutrophic pond in the vegetation period. The three habitats (metaphyton, isolated and non-isolated open water) showed considerable differences in their taxa and functional group composition. Abundance-based diversity measures did not reveal remarkable differences among the assemblages of the three habitats. However, taxonomic and functional richness of the metaphyton and the non-isolated part of the pelagial significantly exceeded that of the limnocorral. Incidence-based similarity index values also showed closer resemblance of the metaphyton and plankton samples compared to that of the limnocorral. In the case of several functional groups, their functional redundancy in the metaphyton exceeded that in the open water areas. These results suggest that the metaphyton provides a refuge for several euplanktic elements that survive in the littoral and occasionally enrich the phytoplankton of the open water areas, representing that a within–lake metacommunity processes shape the composition and functioning of the open water areas in standing waters. [ABSTRACT FROM AUTHOR]

Grass carp (Ctenopharyngodon idellus) is the most productive freshwater fish in China, but its traditional aquaculture model still has problems, such as poor water quality and frequent diseases. We have taken monoculture and 80:20 polyculture grass carp ponds as the research object and used EwE software to build the Ecopath model of two ponds. We analyzed and compared the characteristics of ecological structure and energy flow in two ponds. The result showed the highest effective trophic level in the polyculture pond that was higher than that in the monoculture pond, and fish in polyculture had higher EE values which showed the production of fish in polyculture contributed more to the energy conversion efficiency of the ecosystem. Flows into detritus were the largest component of TST both in the two ponds, which accounted for 49.34% and 50.37%. And the average transfer efficiency in monoculture was 13.07%, while that in polyculture was 15.6%. The ascendency/total development capacity (A/TDC) and overhead/total development capacity (O/TDC) were 0.35 and 0.65 both in the two ponds, respectively, which indicated that both systems had a strong anti-perturbation ability, but the stability could be improved. Finn's cycling index (FCI) in polyculture was higher and showed that the polyculture pond was more mature and stable. Unused energy of functional groups will flow to detritus, and that in the monoculture pond was higher, the energy of C. idellus that flowed to detritus in monoculture was 48.17% higher than that in polyculture; unused energy of bacteria and phytoplankton were also high. The result showed that polyculture could improve energy utilization, increase transfer efficiency, and raise the stability of the ecosystem. Grass carp ponds still need to be improved in the aspects of mixed species and energy consumption. It is necessary to improve the ecological and economic benefits of grass carp ponds by optimizing the aquaculture structure and adjusting the aquaculture proportion. [ABSTRACT FROM AUTHOR]

What a strain is and how many strains make up a natural bacterial population remain elusive concepts despite their apparent importance for assessing the role of intra-population diversity in disease emergence or response to environmental perturbations. To advance these concepts, we sequenced 138 randomly selected Salinibacter ruber isolates from two solar salterns and assessed these genomes against companion short-read metagenomes from the same samples. The distribution of genome-aggregate average nucleotide identity (ANI) values among these isolates revealed a bimodal distribution, with four-fold lower occurrence of values between 99.2% and 99.8% relative to ANI >99.8% or <99.2%, revealing a natural "gap" in the sequence space within species. Accordingly, we used this ANI gap to define genomovars and a higher ANI value of >99.99% and shared gene-content >99.0% to define strains. Using these thresholds and extrapolating from how many metagenomic reads each genomovar uniquely recruited, we estimated that –although our 138 isolates represented about 80% of the Sal. ruber population– the total population in one saltern pond is composed of 5,500 to 11,000 genomovars, the great majority of which appear to be rare in-situ. These data also revealed that the most frequently recovered isolate in lab media was often not the most abundant genomovar in-situ, suggesting that cultivation biases are significant, even in cases that cultivation procedures are thought to be robust. The methodology and ANI thresholds outlined here should represent a useful guide for future microdiversity surveys of additional microbial species. What a microbial strain is and how many strains make up a natural bacterial population remain elusive concepts. Here, Viver et al. analyse Salinibacter ruber isolates and metagenomes from two solar salterns, revealing gaps within the species sequence space that they use to define and quantify sub-species categories, such as genomovars and strains, that co-exist in a saltern pond. [ABSTRACT FROM AUTHOR]

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The (ultra-)mafic mine tailings pond revealed a weathering discrepancy in the tailings profile, which provided a valuable analog to assess the role of carbonate and silicate weathering of the basalt. In this study, drill-cores samples were selected from the Wanniangou V–Ti–Fe mine tailings pond (Sichuan province, China) to investigate the mineralogicand geochemical characteristics in the tailings profile. The results reveal (1) the tailings pond profile consist of upper and lower layers. The upper layer is composed of carbonate weathering (1.4 %), which was formed in the initial stages of tailings exposure and represented a minimal weathering degree. (2) The lower layer was primarily observed at the aquifer zone of the tailings pond, and was consistent with 0.45 % carbonate weathering and 48.4 % silicate weathering. (3) The weathering discrepancy in the tailings profile could be due to the sulfide oxidation and aerobic/flowing aquifer, which facilitate the water-tailings reactions. The tailings profile provides an analog to studying basalt weathering, as it spans both carbonate and silicate weathering. This research reinforces the idea that silicate weathering is predominant in basaltic areas and plays a crucial role in regulating atmospheric CO2 (carbon dioxide) levels on Earth. [ABSTRACT FROM AUTHOR]

Large branchiopods are a key component of the fauna of temporary ponds and play an important role in the functioning of these vulnerable ecosystems. Owing to the establishment of new settlements and agricultural expansion, temporary ponds in Tanzania are disappearing at an alarming rate whilst little is known about their diversity and ecology. We contrasted temporary ponds from a protected area with those in communal lands to detect associations between land-use types and large branchiopod community structure. Six large branchiopod species were collected, five of which have been previously reported from Southern Africa, whilst one turned out to be new to science: Streptocephalus manyarensis n.sp. Kafula and Brendonck (2023). The clam shrimp Cyzicus sp., fairy shrimps Streptocephalus lamellifer Thiele (1900) and S. bourquinii Hamer and Appleton (1993) were the most abundant and widely occurring. Variation in large branchiopod community structure was explained by the presence of Nothobranchius killifish and orthophosphate concentration. The large branchiopod community structure was different in settlement and protected areas. Our study on the occurrence and structure of large branchiopod communities in relation to land-use types serves as a base for formulation of guidelines and management tools to regulate land-use practices adjacent to temporary pond ecosystems. [ABSTRACT FROM AUTHOR]

Analysis of available monitoring data sets on concentrations of accidentally derived dissolved radiocesium in water bodies is indicative of two major physicochemical mechanisms responsible for their seasonal variations in water bodies in the course of the year: temperature dependence of radiocesium desorption from suspended material and ion-exchange remobilization of radiocesium by ammonium cations formed during decomposition of organic matter in anoxic conditions. An equation describing seasonal variations in concentration of dissolved radiocesium in water bodies has been derived accounting for two factors: water temperature, and combined concentration of key competing cations. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying chemical and biological quality characteristics of the aquatic environment in the area of operation of trout farms in Kondopoga Bay, Onega Lake. The concentrations of biochemically labile substances and phosphorus were found to increase near the ponds. The development dynamics of phytoplankton, zooplankton, and benthic organisms in the zone of pond farms. When the procedure of fish production is strictly followed, the effect of ponds on the aquatic environment and biota is minimal. [ABSTRACT FROM AUTHOR]

Mediterranean temporary ponds (MTPs) is a priority habitat according to the Natura 2000 network of the European Union (Natura code 3170, Habitats Directive 92/43/EEC) and is located in various Mediterranean countries. Priority habitats are those habitat-types or elements with a unique or important significance to a diverse group of species. They consist of a unique flora composition, succession stage and/or structural factor. Increased urbanisation and agriculture in addition to climate change, in the Mediterranean region, has led to the extinction of a very large number of temporary ponds. This paper is a review of the value and the numerous threats, concerning MTPs. Protection and conservation of the ponds is very important and appropriate managerial measures should be immediately taken, to save such a vulnerable ecosystem. [ABSTRACT FROM AUTHOR]