Search Results (80)

(1) Although lotus ponds exhibit ecological benefits in wetland restoration, their efficacy in water purification and eutrophication mitigation remains unclear. (2) This study utilized Jinluo lotus pond as the experimental group and the adjacent river as the control. Five sampling points were established in each area, with water samples collected in June 2022, April 2025, and May 2025. (3) The pH, BOD, COD, TN, and NH₃-N concentrations in Jinluo lotus pond water are higher than those in rivers, while the TP, NO₃-N, Chl-a, and algal cell density in rivers are higher. However, there was no significant difference in the nine parameters (p > 0.05) in June 2022. The pH, DO, algal cell density, and algal biomass of the Jinluo lotus pond were significantly higher (p < 0.05 for DO); the concentrations of BOD, COD, TN, TP, NH₃-N, NO₃-N, PI, and Chl-a in rivers are higher, with significant differences in Chl-a (p < 0.05) in April 2025. The BOD, COD, TP, NO₃-N, and PI of the Jinluo lotus pond were relatively high (p < 0.05 for PI); the pH, TN, NH₃-N, DO, Chl-a, algal cell density, and algal biomass of rivers are higher, with significant differences in Chl-a (p < 0.05) in May 2025. The results showed that there was no significant difference in the four diversity indicators in June 2022, April 2025, and May 2025. There was no significant difference in the algal diversity indices, including species richness (S), Shannon–Wiener diversity index (H), Simpson diversity index (P), and Pielou evenness index (E) between Jinluo lotus pond and rivers. (4) Conclusions and Recommendations: The Jinluo lotus pond and adjacent rivers suffer from severe nutrient overload, especially with BOD, COD, and TN all being classified as Class 5 water. Expanding natural and constructed reed communities is recommended to enhance nutrient removal. However, given the limited purification capacity of lotus ponds, maintaining or increasing their area may not be justified. Full article

During intensive aquaculture of Eriocheir sinensis (E. sinensis), wastewater containing feed additives, heavy metals, and antibiotics can cause water eutrophication and lead to the accumulation of complex pollutants in sediments. In this study, heavy metals and antibiotic resistance genes (ARGs) were analyzed for their distribution and accumulation patterns via ICP-OES and qPCR, and their correlations with bacterial communities in sediments from E. sinensis ponds were evaluated using co-occurrence network and redundancy analysis. Our results demonstrated that aquaculture activities significantly elevated the concentrations of heavy metals such as Cadmium (Cd) and Manganese (Mn) in the sediments, and Cd was identified as the dominant factor contributing to the increase in the potential ecological risk index (RI). The abundance of ARGs significantly increased, with sulfonamide resistance genes (sul1, sul2), β-lactam resistance genes (blaTEM), and integron-associated genes (intl1) showing the highest levels. Correlation and redundancy analyses showed that most ARGs were positively correlated with and linked to Proteobacteria, Bacteroidetes, and Dechloromonas as potential hosts. Positive correlations were generally observed among heavy metals, suggesting a common source, namely aquaculture wastewater, and some showed positive associations with Acidobacteria. This study provides a theoretical basis for further understanding the distribution, accumulation patterns, and coupling relationships of heavy metals and ARGs, as well as their relation and effects on bacterial communities in the sediment of E. sinensis ponds. Full article

With the rapid development of urbanization in rural areas of China, various environmental issues have become increasingly prominent, particularly the water pollution problems in small rural watersheds, which have garnered considerable attention. Comprehensive management of small watersheds requires an initial analysis of the sources and characteristics of water pollution. This study focuses on small rural watersheds in the Pearl River Delta. Based on the characteristics of the watersheds, 35 water quality monitoring stations were set up to collect water quality data. Cluster analysis was used to study the spatial distribution characteristics of water quality indicators at each monitoring point. Further, factor analysis methods (PCA/FA) and Absolute Principal Component Scores-Multiple Linear Regression (APCS-MLR) models were employed to identify water quality influencing factors and quantify pollution source contributions. Finally, the comprehensive index method for eutrophication assessment was used to evaluate and analyze the potential eutrophication pollution risk in the watersheds. The results indicate significant pollution in the water quality of rural small watersheds in the study area, with varying degrees of pollution over time and space. During the wet season, water quality is mainly influenced by agricultural nutrients, followed by biochemical factors. In the normal and dry seasons, water quality is primarily affected by oxygen-consuming organic pollutants, followed by eutrophication factors. The comprehensive eutrophication evaluation shows that the overall water quality in the watershed is better during the wet season, with a lower risk of eutrophication; during the normal season, the overall water quality is poorer, with the highest eutrophication risk in the midstream; during the dry season, the upstream and midstream water quality is better, while the downstream water quality is poorer. In contrast, the pond water exhibits a higher risk of eutrophication during the wet season compared to the normal and dry seasons. This is mainly due to the peak of fish farming during the wet season, which results in a heavier load on the water body. This study provides effective data support for the water environment management of rapidly developing rural small watersheds. Full article

Fishponds are regarded as hypertrophic systems accompanied by low biodiversity. We focused on the phytoplankton diversity of 15 fishponds located in Austria. Of the 15 fishponds, 12 waterbodies are aquaculture ponds stocked with common carp, which converted to organic farming some years ago with grain as supplementary feed, and 3 ponds are used for recreational fishing. The trophic state index increased from 59 to 71 in spring to 80 to 93 in autumn and classified the ponds as mid-eutrophic to hypertrophic. The taxa number was surprisingly high (taxa richness up to 100 taxa per pond). The phytoplankton resource use efficiency was in the upper range of eutrophicated waters and did not show seasonal differences (median Chlorophyll-a/total phosphorus = 1.94, Chlorophyll-a/total nitrogen = 0.12). Linking environmental data with the algal community resulted in a distinct temporal community pattern with a significant seasonal shift from the cooler season dominated by Ochrophyta taxa to green algae as the most abundant group in summer and autumn. Our findings challenge general assumptions regarding low phytoplankton diversity with long-lasting Cyanobacteria blooms and conform to the algal dynamics described in the plankton ecology group (PEG) model for temperate shallow lakes. These man-made systems are an ecological asset, highly connected to terrestrial habitats in their vicinity and significantly contributing to the ecological health and long-term sustainability of the region. Full article

The urban water environment, an integral component of the terrestrial hydrosphere, is closely linked to human activities and serves as a fundamental resource for industrial and agricultural development. Sedimentary organic matter in water bodies contains rich biological, physical, and chemical information, playing a central role in nutrient cycling and serving as a primary reservoir for nutrient accumulation. This study assesses the water quality, chemical indicators, and sediment productivity of four typical urban water bodies (Canal, Pond, Lake, and River) in Shaoxing City, eastern China. The results show that artificial water bodies, particularly canals, have higher dissolved oxygen (DO) compared to natural water bodies. Stationary water bodies, such as lakes and ponds, generally have higher total dissolved solids (TDS) and electrical conductivity (EC) than flowing water bodies like rivers and canals. All four urban water body types slightly exceed China’s Class-V water quality standard for total nitrogen (TN), with canals, lakes, ponds, and rivers averaging 1.29, 1.22, 1.23, and 1.23 times the standard, respectively. Ponds exhibit the highest total dissolved nitrogen (TDN) content, while ammonium (NH₄⁺–N) and nitrate (NO₃⁻–N) levels are relatively consistent across the bodies, except for lower NO₃⁻–N in lakes. Higher organic matter in canals and lakes, indicated by chlorophyll-a (Chl-a) and permanganate index (COD_Mn), suggests greater eutrophication compared to ponds and rivers. Sediment total organic nitrogen (TON) content is relatively uniform across all water bodies, with slightly higher values in lakes and rivers. Total organic carbon (TOC) content is highest in lake sediments, 1.51 times that of canals. Carbon/nitrogen (C/N) ratios vary, with ponds and lakes showing the highest averages. Source quantification using isotopic analysis (δ¹³C and δ¹⁵N values) indicates that phytoplankton is the primary sedimentary organic matter source in rivers and canals, while terrestrial sources are significant in lakes and ponds. Sewage notably contributes to rivers and canals. These findings highlight the need for targeted pollution control strategies, focusing on phytoplankton and sewage as key sedimentary organic matter sources to mitigate eutrophication and enhance water quality in urban environments. Full article

Urban and storm water retention ponds eventually become eutrophic after years of receiving runoff water. In 2020, a novel biological and chemical treatment was initiated to remove accumulated nutrients from an urban retention pond that had severe algae and weed growth. Our approach installed two 6.1 m × 6.1 m floating treatment wetlands (FTWs) and two airlift pumps that contained slow-release lanthanum composites, which facilitated phosphate precipitation. Four years of treatment (2020–2023) resulted in median nitrate-N concentrations decreasing from 23 µg L⁻¹ in 2020 to 1.3 µg L⁻¹ in 2023, while PO₄-P decreased from 42 µg L⁻¹ to 19 µg L⁻¹. The removal of N and P from the water column coincided with less algae, weeds, and pond muck (sediment), and greater dissolved oxygen (DO) concentrations and water clarity. To quantify the sustainability of this bio-chemical approach, we focused on quantifying nitrate removal rates beneath FTWs. By enclosing quarter sections (3.05 × 3.05 m) of the field-scale FTWs inside vinyl pool liners, nitrate removal rates were measured by spiking nitrate into the enclosed root zone. The first field experiment showed that DO concentrations inside the pool liners were well below the ambient values of the pond (<0.5 mg/L) and nitrate was quickly removed. The second field experiment quantified nitrate loss under a greater range of DO values (<0.5–7 mg/L) by including aeration as a treatment. Nitrate removal beneath FTWs was roughly one-third less when aerated versus unaerated. Extrapolating experimental removal rates to two full-sized FTWs installed in the pond, we estimate between 0.64 to 3.73 kg of nitrate-N could be removed over a growing season (May–September). Complementary laboratory mesocosm experiments using similar treatments to field experiments also exhibited varying nitrate removal rates that were dependent on DO concentrations. Using an average annual removal rate of 1.8 kg nitrate-N, we estimate the two full-size FTWs could counter 14 to 56% of the annual incoming nitrate load from the contributing watershed. Full article

Ponds are important habitats for aquatic plants and other biota, particularly in regions where the quality of aquatic ecosystems is deteriorating or even disappearing. Ponds provide refuge for many species and serve as foraging places for others. The ponds studied are located in the Brdo Estate and are under special protection to maintain their educational and other ecosystem services. This study examined the temporal differences (20 years) of the plant communities in eleven ponds concerning eutrophication and/or other human pressures. Various measurements were taken between the two surveys to improve the quality of inflowing water. The selected ponds’ physical and chemical parameters, water depth, and transparency were measured. According to our results, water transparency and temperature significantly shaped the structure of the plant community and significantly influenced the presence and abundance of aquatic plants. The changes were reflected in the disappearance of four species of the genus Potamogeton, namely P. filiformis, P. lucens, P. pectinatus, and P. trichoides, which were recorded in 2001 but not in 2021. Secondly, the average number of plant species in the ponds has slightly increased in 20 years, mainly due to emergent plants. The construction of wastewater treatment plants in the catchment area prevented the eutrophication processes. Full article

Softwater ponds with Lobelia dortmanna (EU habitat type 3110) represent the rarest aquatic habitat in Belgium. As in many other European countries, its unfavourable conservation status necessitates restoration according to the EU Habitats Directive, which is compromised by a range of pressures and faces increasing social–economic opposition. To explore appropriate goals and remaining obstacles for its ecological rehabilitation, we investigated the environmental history of a pond, formerly renowned for the occurrence of this habitat. We complemented monitoring data with information inferred from diatoms analysed from old samples, herbarium specimens and surface sediments, vegetation records, physical–chemical analyses and additional observations. This indicated almost circumneutral, slightly buffered and nutrient-poor conditions for the first decades of the 20th century. Deposition of atmospheric pollutants caused gradual acidification from the early 1940s, intensifying into mineral-acidic conditions by the 1970s. More recently, a period of alkalinisation and eutrophication followed despite some restoration efforts. We discuss these changes in the contexts of general setting, external pressures and internal processes. Reflecting upon the prospects for restoring the pond’s emblematic biodiversity, management implications for this and other softwater sites dealing with similar problems are discussed. A new combination in the diatom genus Iconella is proposed. Full article

Estuary ecosystems serve as crucial connectors between terrestrial and marine environments, thus playing vital roles in maintaining the ecological balance of coastal marine ecosystems. In recent years, the eutrophication in estuaries caused by aquaculture sewage has been revealed, highlighting the necessity to understand its influence on the nutrient conditions and carbon storage of estuaries. In this study, δ¹⁵N and δ¹⁸O were used to indicate the contribution of aquaculture-derived sewage to dissolved inorganic nitrogen in Zhangjiang Estuary, and δ¹³C and C:N ratio were used to reveal its effects on the particulate organic matter. The major results are as follows: (1) Aquaculture water contributed 62~86% and 60~100% of the total nitrate and ammonium in Zhangjiang Estuary, respectively, and the drainage periods of the cultured species has a great influence on the content and composition of dissolved inorganic nitrogen. (2) Aquaculture water was also the major source of particulate organic matter (24~33% of the total content) here, most of which may be derived from crab ponds. (3) The imports of nutrients by aquaculture water may potentially regulate particulate organic matter in Zhangjiang Estuary by promoting the growth of phytoplankton and zooplankton. Our study revealed the coupling effects of aquaculture activities on the nitrogen and carbon storage in an estuarine ecosystem. It also indicates that isotopes may be efficient in the monitoring of a coastal environment, which may further aid the management of inshore cultivation. Full article

The study investigates water quality in a small water body in an agricultural catchment in a zone of temperate climate (East Poland). The pond is affected by annual mass cyanobacterial blooms, limiting its use. The improvement of the state of water quality involved the application of underwater aerating reactors. The economic analysis of their application was also an important issue. The analysis of the effectiveness of the proposed solution was conducted from February to October 2021. The results from the analysis of water from the pond showed that the nutrient content and phytoplankton structure conformed to the trophic status of eutrophy–hypertrophy. The primary factors causing excessive eutrophication of the pond included nutrient supply from the river, sediments, and fallen tree leaves. No development of cyanobacterial scum was observed in the water body, a phenomenon which was interpreted as the effect of the operation of the aerators ensuring additional water circulation in the pond and promoting its aeration. It was found that permanent improvement of the water quality in the studied water body is largely dependent on limiting the nitrogen and phosphorus supply to the pond. This should involve the application of systems combining traditional hydrotechnical infrastructure with Nature-Based Solutions (NBS). The economic analysis of the use of underwater aeration reactors confirmed the validity of searching for alternative solutions to power them, e.g., a photovoltaic installation. When designing a reactor system with a photovoltaic installation, it is necessary to choose the correct dimensions to reduce construction costs and, thus, increase the profitability of the potential investment. Full article

Aquaculture plays a vital role in global food production, with fish pond water quality directly impacting aquatic product quality. The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) serves as a key producer of aquatic products in South China. Monitoring environmental changes in fish ponds serves as an indicator of their health. This study employed the extreme gradient boosting tree (BST) model of machine learning, utilizing Landsat imagery data, to assess Chlorophyll-a (Chl-a) concentration in GBA fish ponds from 2013 to 2022. The study also examined the corresponding spatiotemporal variations in Chl-a concentration. Key findings include: (1) clear seasonal fluctuations in Chl-a concentration, peaking in summer (56.7 μg·L⁻¹) and reaching lows in winter (43.5 μg·L⁻¹); (2) a slight overall increase in Chl-a concentration over the study period, notably in regions with rapid economic development, posing a heightened risk of eutrophication; (3) influence from both human activities and natural factors such as water cycle and climate, with water temperature notably impacting summer Chl-a levels; (4) elevated Chl-a levels in fish ponds compared to surrounding natural water bodies, primarily attributed to human activities, indicating an urgent need to revise breeding practices and address eutrophication. These findings offer a quantitative assessment of fish pond water quality and contribute to sustainable aquaculture management in the GBA. Full article

The aim of this study was to investigate the dynamic changes in the microbial communities of both the environment and gut of Litopenaeus vannamei, as well as to elucidate the mechanisms underlying microbial community assembly in greenhouse farming. 16S rDNA high-throughput sequencing and bioinformatics methods were used to carry out the research on the community structure of the microorganisms under greenhouse culture conditions in water, sediment, and gut microorganisms; correlations pertaining to environmental factors; the feasibility of using Source Tracker; and the mechanisms of community construction. The results show that the dominant microorganisms in water, sediment, and gut farming in a greenhouse environment varied and were subject to dynamic change. A variety of beneficial microbiota such as Bacillus were found in the gut, whereas a variety of microorganisms such as Marivita and Pseudomonas, which function as nitrogen and phosphorus removers, were present in water. Source Tracker and environmental correlation analyses showed that changes in the gut were associated with eutrophication indicators (total nitrogen, total phosphorus, ammonia nitrogen) and changes in environmental microorganisms (in water and sediment). The results of the community-building mechanism analysis show that stochastic processes determine the community-building directions of environmental and gut microorganisms. These findings will help us to understand the microbiota characteristics of shrimp ponds under greenhouse farming conditions, and the complex interactions between the shrimp gut and the environmental microbiota and environmental variables, as well as revealing the changing rules of the gut microbiota. Full article

The efficient management of slurry, which is a by-product rich in nutrients derived from feces, urine, cleaning water, and animal waste that stands out for its high concentration of nutrients such as nitrogen, phosphorus, and potassium, is of vital importance, highlighting the importance of slurry management in storage ponds, which. The Murcia–Spain region has an important number of pig farms. Hence, infrastructures dedicated to managing by-products are necessary to prevent environmental pollution and eutrophication of groundwater. The aim of a recent study was to evaluate the relationship between electrical values and geochemical parameters of pig slurry stored in a pond using ERT and geochemical analysis. In addition, the study was designed to monitor the pond to determine the geochemical characteristics of the slurry and to assess the risk of lateral contamination. The study results indicate a noticeable decrease in electrical resistivity values at 0.4 and 1.6 m depth in surveys 1 and 2. The reduction ranges from 50 to 100 percent. This paper presents a new method for monitoring slurry ponds using electrical resistivity tomography. This non-invasive method provides detailed information on the distribution and characteristics of the fluids, as well as a clear picture of the electrical resistivity of the subsurface. Full article

Cercarial dermatitis (CD), or “Swimmer’s itch” as it is also known, is a waterborne illness caused by a blood fluke from the family Schistosomatidae. It occurs when cercariae of trematode species that do not have humans as their definitive host accidentally penetrate human skin (in an aquatic environment) and trigger allergic symptoms at the site of contact. It is an emerging zoonosis that occurs through water and is often overlooked during differential diagnosis. Some of the factors contributing to the emergence of diseases like CD are related to global warming, which brings about climate change, water eutrophication, the colonization of ponds by snails susceptible to the parasite, and sunlight exposure in the summer, associated with migratory bird routes. Therefore, with the increase in tourism, especially at fluvial beaches, it is relevant to analyze the current epidemiological scenario of CD in European countries and the potential regions at risk. Full article

Dredging, adsorbent inactivation, and phytoremediation are commonly used to control internal nitrogen and phosphorus sediment loads in eutrophic still-water ecosystems, such as lakes and ponds. However, the effectiveness of these remediation techniques has not been verified for rivers, lakes, and reservoirs with large disturbances. In this study, a calcium-loaded clay granular adsorbent (CRB) was prepared as an alternative to commercial adsorbents, and an experiment was conducted on the ecological restoration effects of both dredging and adsorbent single treatments as well as combined treatments on eutrophic flowing water. The enhancement effect of phytoremediation on the above restoration techniques was investigated. The results indicated that CRB inactivation treatment reduced the phosphorus and turbidity of the water by 63% and 80%, respectively and increased the total nitrogen and permanganate index (COD_Mn) by 25% and 101% before phytoremediation, respectively compared to the control group. There were no significant differences in the nutrient indexes of the sediment and water between the dredging treatment and the control group, but dredging enhanced the effect of the CRB treatment. Compared with the CRB treatment, the total nitrogen and COD_Mn of water in the dredging and combined CRB treatments decreased by 13% and 15%, respectively. Phytoremediation significantly improved the effectiveness of the dredging and adsorbent treatments, both individually and in combination. Additionally, there were notable differences in the growth rates of the submerged plants and the contents of different phosphorus speciation among the plant species. Selecting suitable plant species is recommended when implementing phytoremediation methods. This study highlights that the combination of multiple restoration techniques is effective for eutrophic flowing water. The results provide a guide for the ecological restoration of flowing water. Full article