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Aim: Over the last century, lakes all over the world have experienced significant eutrophication and become more susceptible to critical transitions. This has prompted a growing need to understand how community dynamics shift following ecological perturbations. This study aims to elucidate the present status, spatial patterns and determinants of biological diversity, and how they have changed in response to alterations driven by eutrophication. Location: Lakes of East China, mostly in the Yangtze River Basin. Taxa: Bacillariophyceae (163 species in 33 genres, see taxa names in Appendix S1). Methods: The environmental conditions of over 60 lakes were assessed based on parameters such as water quality, physical characteristics and biogeochemical constituents. Surface sediment samples and high‐resolution sediment records were collected to quantify the biodiversity of diatom communities, and principal component analysis (PCA) was used to determine the major environmental gradients. Meanwhile, linear regression, canonical correlation analysis and Mantel tests were used to quantify the correlations between variables. Results: Biodiversity metrics showed no distinct geographic patterns, although areas near large lakes showed comparatively high evenness. Smaller pairwise dissimilarities were observed among hypereutrophic lakes in comparison to lakes with a lower trophic status. The past century has witnessed a decrease in both pairwise dissimilarity and the standard deviation of evenness. A significant statistical association was found between dissimilarity and ionic concentration and composition in the surface sediment of lakes, rather than nutrient levels. Main Conclusions: Following regional eutrophication and human disturbance, a significant reduction in biodiversity differentiation was observed in lakes located in East China. Currently, the dominant factor in determining the beta diversity of diatom communities is geochemical conditions rather than nutrient concentrations. Long‐term stress caused by cultural eutrophication may also have altered the dominant determinant of regional biodiversity and diatom community dynamics. [ABSTRACT FROM AUTHOR]

Aim: Decreasing in the diversity and distribution of native submerged plants have been widely observed in recent decades. Global underwater darkening, which is mainly caused by radiation dimming and a decrease in transparency due to, e.g. eutrophication, has emerged as a general trend that strongly hampers the growth of submerged plants in lakes by decreasing the light available for photosynthesis. However, few studies have attempted to compare the responses of native and invasive submerged plants to underwater darkening. In this study, we aimed to compare the effects of light attenuation on the growth and photosynthesis traits of native and invasive submerged plants. Location: East China. Method: Through field investigations and a mesocosm experiment, the responses of functional traits of two representative native [water thyme (Hydrilla verticillata), Eurasian watermilfoil (Myriophyllum spicatum)] and one invasive [Carolina fanwort (Cabomba caroliniana)] plant species to various environmental factors, notably to underwater light attenuation, were studied. Results: Underwater photosynthetically active radiation (PAR) exerted a substantial effect on the relative coverage and abundance of the three studied submerged plants in their natural freshwater habitats. Invasive C. caroliniana showed relatively superior growth (total biomass and relative growth rate) and photosynthesis traits (maximum quantum yield of photosystem II Fv/Fm, chlorophyll a content, chlorophyll b content and the ratio of Chl a and b contents) compared to the two native plants under low underwater PAR conditions. In contrast, under high underwater PAR conditions, C. caroliniana showed the opposite response. Main Conclusions: Light attenuation inhibits the growth of native submerged plants but facilitates the growth of invasive plant species. Restoration of freshwater lakes by reducing deterioration from underwater darkening (for instance, by reducing of external nutrients loading) may therefore constrain the growth and spread of the invasive C. caroliniana. [ABSTRACT FROM AUTHOR]

Microbiota play essential roles in nitrogen (N) cycling in freshwater river ecosystems. However, our understanding of microbial functional groups associated with N cycling (especially denitrification) in freshwater rivers under anthropogenic disturbance is still poor. Here, we studied the impacts of different land‐use types on denitrification‐related microbiota in the Weihe River, Hanjiang River, and their tributaries, in the Qinling Mountains, China. The major land‐use types in the three river areas were divided into natural (forest, shrub, grassland, and open water) and anthropogenic (agricultural and urbanized land) types. A landscape survey of microbiota in the river water and sediment was carried out with extensive sample sources based on deep 16S rRNA gene sequencing, which yielded operational taxonomic units for predicting functional groups. With increases in proportions of agricultural and urbanized land areas, electrical conductivity, total N, ammonium‐N, and nitrate‐N all increased in water samples. Conversely, microbial diversity exhibited a decreasing trend in water samples, whereas the relative abundance of denitrification‐related functional groups increased, with increases in the proportions of agricultural and urbanized land areas. The relative abundances of denitrification‐ and human‐related microbial functional groups in sediment samples were distinctively higher in Weihe River (mainly under agriculture and urbanization), when compared with those of Hanjiang River and Qinling tributaries (dominated by forests). The results indicate that anthropogenic land‐use types, such as agricultural and urbanized land, result in simple microbial community structure and stimulate microbe‐mediated denitrification in freshwater rivers. [ABSTRACT FROM AUTHOR]

In order to study the seasonal changes of the freshwater zooplankton functional groups and the impact of water environment in cold temperate wetlands in China, nine sampling sites were selected in Genheyuan nature reserve in spatiotemporal of 2020. The results showed that we found seven functional groups, including protozoa filter feeders (PF), rotifer filter feeders (RF), rotifer carnivore (RC), small copepodas and cladocera filter feeders (SCF), middle copepodas and cladocera carnivore (MCC), large copepodas and cladocera carnivore (LCC) and large copepodas and cladocera filter feeders (LCF). In spring, the PF (54.32%) and RF (39.5%) functional groups were dominant. In summer, the PF was contributing 93.2%. In autumn, the PF (54.64%) and RF (44.62%) were dominant. The seasonal succession was characterzed by PF+RFPF+RF+RCPF+RF+MCC, which indicates that the filter feeding zooplankton usually dominates in three seasons, resulting in a long-term poor trophic state of the water. Pearson correlation analysis and redundancy analysis multivariate statistical analysis showed that the chemical oxygen demand, dissolved iron and pH were the mainly influencing fators. Our finding has certain reference significance for the freshwater wetlands management and protection in the cold temperate zone. [ABSTRACT FROM AUTHOR]

Simple Summary: From 2019 to 2020, 28 species of fish were collected from the upper reaches of the Jinsha River. The dominant species of fish were Triplophysa stenura, Schizothorax wangchiachii, and Schizopygopsis malacanthus. Fish diversity was at a deficient level, and flow velocity, altitude, and dissolved oxygen were the main influencing factors causing the differences in fish community structure in the upper Jinsha River. The abundance/biomass curve showed that the fish community in the upper Jinsha River was moderately or seriously disturbed. The standardized biomass size spectrum of fish showed that the degree of disturbance of fish in tributaries was much lower than that in the main stream. Compared with the historical data, the structure of the fish community in the Jinsha River changed significantly, with more exotic species and smaller individual fish. It is suggested that habitat conservation strategies be adopted in the upper tributaries of the Jinsha River to provide a reference for the restoration of fishery resources and the conservation of fish diversity in the Yangtze River. To understand the characteristics of the fish community structure and biomass particle-size spectrum in the upper reaches of the Jinsha River, fish and environmental surveys were conducted in 21 segments of the upper reaches of the Jinsha River in September 2019 and June 2020. A total of 4062 fish belonging to 2 orders, 5 families, 18 genera, and 28 species were collected. Among them, Cyprinidae fish were the most abundant (14 species), accounting for 50.00%. The Shannon index and Pielou evenness index values varied from 0.402–1.770 and 0.254–0.680, respectively. The dominant species of fish were Triplophysa stenura, Schizothorax wangchiachii, and Schizopygopsis malacanthus. Redundancy analysis (RDA) was used to analyse the relationship between the fish community and environmental factors. Velocity, altitude, and dissolved oxygen were the main influencing factors of fish community structure differences in the upper reaches of the Jinsha River. The abundance/biomass curves showed that the fish communities in the upper reaches of the Jinsha River were moderately or severely disturbed. The standardized biomass particle-size spectrum of fish showed that the degree of disturbance of fish in tributaries was much lower than that in the main stream. Compared with the historical data, the fish community structure in the Jinsha River has changed significantly, with the number of exotic species increasing, and the individual fish showing miniaturization and younger ages. It is suggested that habitat conservation strategies be adopted in the upper tributaries of the Jinsha River to provide a reference for the restoration of fishery resources and the conservation of fish diversity in the Yangtze River. [ABSTRACT FROM AUTHOR]

Aim: The invasion of exotic macrophytes causes native biodiversity loss in aquatic ecosystems of China. However, the influence of invasive free‐floating macrophytes on epiphytic algal communities has rarely been reported, especially in comparison with those of native free‐floating macrophytes. Region: Southern China. Methods: We investigated the interrelationship between epiphytic algal communities on the roots of three free‐floating macrophytes [two invasive species (Eichhornia crassipes and Pistia stratiotes) and one native species (Hydrocharis dubia)] and environmental factors in 40 natural freshwater ecosystems throughout southern China. We also tested the relationship between allelochemicals from the macrophytes and epiphytic algae. A mesocosm experiment was conducted to verify the discoveries of the field investigation. Results: The abundance of epiphytic algae on the invasive macrophytes was lower than that on the native species in the field investigation and mesocosm experiment. Macrophyte traits were the main factor explaining the epiphytic algal abundance in both the field investigation and mesocosm experiment. In linear models, the slopes of epiphytic algal abundance were lower across gradients of native macrophyte biomass and coverage than across gradients of invasive macrophyte biomass and coverage. The allelochemical contents secreted by the invasive macrophytes were significantly higher than those secreted by the native species. The composition of allelochemicals was another factor that drove the decrease in epiphytic algal abundance. Among the allelochemicals, organic acids and alkaloids were abundant. Main Conclusions: The inhibitory effect of two invasive free‐floating macrophytes on epiphytic algae is stronger than that of the native macrophyte H. dubia. The main reason for this finding is that the invasive macrophytes have greater biomass and occupied more space, resulting in greater limitations on spatial niches and resources. Moreover, invasive macrophytes release more allelochemicals than native macrophytes, leading to stronger inhibitory effects on epiphytic algae. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems face multiple threats to their stability globally. Poyang Lake is the largest lake in China, but its habitat has been seriously degraded because of human activities and natural factors (e.g. climate change), resulting in a decline in freshwater biodiversity. Zooplankton are useful indicators of environmental stressors because they are sensitive to external perturbations. DNA metabarcoding is an approach that has gained significant traction by aiding ecosystem conservation and management. Here, the seasonal and spatial variability in the zooplankton diversity were analyzed in the Poyang Lake Basin using DNA metabarcoding. The results showed that the community structure of zooplankton exhibited significant seasonal and spatial variability using DNA metabarcoding, where the community structure was correlated with turbidity, water temperature, pH, total phosphorus, and chlorophyll‐a. These results indicated habitat variations affected by human activities and seasonal change could be the main driving factors for the variations of zooplankton community. This study also provides an important reference for the management of aquatic ecosystem health and conservation of aquatic biodiversity. [ABSTRACT FROM AUTHOR]

Emerging contaminants (ECs) are increasingly recognized as a global threat to biodiversity and ecosystem health. However, the cumulative risks posed by ECs to aquatic organisms and ecosystems, as well as the influence of anthropogenic activities and natural factors on these risks, remain poorly understood. This study assessed the mixed risks of ECs in Dongting Lake, a Ramsar Convention-classified Typically Changing Wetland, to elucidate the major EC classes, key risk drivers, and magnitude of anthropogenic and natural impacts. Results revealed that ECs pose non-negligible acute (30% probability) and chronic (70% probability) mixed risks to aquatic organisms in the freshwater lake ecosystem, with imidacloprid identified as the primary pollutant stressor. Redundancy analysis (RDA) and structural equation modeling (SEM) indicated that cropland and precipitation were major drivers of EC contamination levels and ecological risk. Cropland was positively associated with EC concentrations, while precipitation exhibited a dilution effect. These findings provide critical insights into the ecological risk status and key risk drivers in a typical freshwater lake ecosystem, offering data-driven support for the control and management of ECs in China. [Display omitted] • 111 emerging contaminants were identified in Dongting Lake, a typical wetland ecosystem. • Multi-level risk assessment revealed non-negligible mixture toxicity of ECs to biota. • Neonicotinoids identified as main risk contributors via prioritization screening method. • Cropland area and precipitation levels drive ECs distribution and ecological risks. [ABSTRACT FROM AUTHOR]

Shihoudian Lake is one of the ecological restoration engineering pilot sites of Baiyangdian Lake, China. To evaluate the phytoplankton characteristics and eutrophication status in Shihoudian Lake, we investigated the community structure of phytoplankton, including the species composition, density, biomass dominance, biodiversity and water quality parameters, in autumn 2018 and spring and summer 2019. The relationships between the community structure and the main environmental factors were analysed using a multivariate statistical method. A total of 143 species of phytoplankton were identified, belonging to 53 genera and eight phyla, and Cyanophyta and Prochlorophyta were the most dominant phyla. Both the density and the biomass were the highest in the summer. A redundancy analysis showed that total phosphorus and chemical oxygen demand were the primary influencing factors of the community distribution of Cyanophyta. Evaluation of the comprehensive diversity index and water quality index revealed that the water of Shihoudian Lake was lightly to moderately polluted, providing scientific evidence for eco-environmental protection and remediation. [ABSTRACT FROM AUTHOR]

The Amazon is the largest river by discharge volume and one of the most biodiverse biomes in the world. Lately, there has been a rapid increase of the urban population in the region, which has been translated into a growing emission of organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) into surface water bodies. This study provides the most comprehensive evaluation of the PAH contamination levels in surface waters of the Amazon basin. We investigated the occurrence and potential sources of 16 priority PAHs and characterised their risks for freshwater ecosystems. For this, we took 40 water samples from different sites along the Brazilian part of the Amazon River, including three major tributaries, and smaller rivers crossing the main urban areas. The results of this study show that PAHs are widespread contaminants in rivers of the Brazilian Amazon. The sum of the total concentration of the 16 priority PAHs reached values of 134 ng L -1 in the Amazon River, and 163 ng L -1 near densely populated areas. On the other hand, the total PAH concentration was generally lower in the monitored tributaries. In most samples, the contamination pattern was dominated by high molecular weight PAHs, suggesting a major contribution of pyrogenic sources, although petrogenic contamination was also present in some locations near urban areas. We assessed ecological risks posed by PAH mixtures using a hazard index. The results indicated that PAH contamination is not likely to pose direct toxic effects for Amazonian freshwater organisms, however continued monitoring is recommended near densely populated areas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Degradation of freshwater ecosystems and the services they provide is a primary cause of increasing water insecurity, raising the need for integrated solutions to freshwater management. While methods for characterizing the multi-faceted challenges of managing freshwater ecosystems abound, they tend to emphasize either social or ecological dimensions and fall short of being truly integrative. This paper suggests that management for sustainability of freshwater systems needs to consider the linkages between human water uses, freshwater ecosystems and governance. We present a conceptualization of freshwater resources as part of an integrated social-ecological system and propose a set of corresponding indicators to monitor freshwater ecosystem health and to highlight priorities for management. We demonstrate an application of this new framework —the Freshwater Health Index (FHI) — in the Dongjiang River Basin in southern China, where stakeholders are addressing multiple and conflicting freshwater demands. By combining empirical and modeled datasets with surveys to gauge stakeholders' preferences and elicit expert information about governance mechanisms, the FHI helps stakeholders understand the status of freshwater ecosystems in their basin, how ecosystems are being manipulated to enhance or decrease water-related services, and how well the existing water resource management regime is equipped to govern these dynamics over time. This framework helps to operationalize a truly integrated approach to water resource management by recognizing the interplay between governance, stakeholders, freshwater ecosystems and the services they provide. [ABSTRACT FROM AUTHOR]

• We develop an integrated method for assessing lake ecosystem health. • Lake ecosystem degradation shows clear spatial heterogeneity patterns in East China. • Identifying the nonlinear contribution of multiple stressors to lake degradation. • Lake ecosystem health is significantly influenced by its distance from the city. Freshwater lake ecosystems face unprecedented challenges with escalating anthropogenic pressure worldwide. An improved understanding of how environmental and socioeconomic factors impact lake health is crucial for strategic conservation and management. Here, we compiled data from 85 lakes from China's most densely populated regions and proposed an integrated index to examine spatial patterns of lake ecosystem health. We further evaluated how 16 socioeconomic drivers and environmental conditions drive these changes by using the Bayesian hierarchical model and Gradient boosting decision tree models. Our results suggest the integrated index can provide a comprehensive picture of lake ecosystem quality from a systems perspective combining water bodies and lakeshore zones. We find that lake degradation shows clear spatial heterogeneity patterns given the common forcings associated with climate factors and land-use practices within this region. We further reveal the non-linear relationships between the social and economic factors (distance, population, food production, gross domestic product [GDP], etc.) and lake ecology, and find that distance of the lake from the city center was the predominant factor that influenced the lake system health among these multiple drivers. This study contributes to the understanding of the differences and driving mechanisms of lake ecological degradation in areas of high human activity as a basis for further identifying environmental conflicts and recommendations to improve the state of lake ecosystems. [ABSTRACT FROM AUTHOR]

Despite the worldwide concern over the impact of microplastics (MPs) and associated organic contaminants, the information regarding the occurrence and characteristics of these emerging class of pollutants is limited in freshwater environment. We present data on the distribution and concentration levels of MPs and phthalate esters (PAEs) from Rewalsar Lake, a shallow eutrophic lake in Northwest Himalaya. The MPs were identified in all samples, with concentration of 13-238 particles L -1 and 750 to 3020 particles kg -1 dry weight (dw) in surface water and sediments respectively. Majority of MPs were dominated by polystyrene, polyethylene, polypropylene polymers that principally occurred in the form of pellets and fragments. The MPs distribution was different among sampling sites, being more abundant to sites in the proximity of domestic sewage effluents and high level of religious and tourist activities. The di-isobutyl phthalate, dibutyl phthalate (DBP) and its branched isomer, di(2-ethylhexyl) phthalate (DEHP) are the identified PAE congeners in sediments, and the measured total concentrations of Σ 3 PAE ranged from 1.69 μg/g to 4.03 μg/g dw. Notably, concentration values of DEHP were higher as compared to other detected phthalates, and exceeded recommended environmental risk limit. The findings of this study emphasize the requirement for proper waste management measures in the region to reduce entry of these pollutants into the ecosystem. Further, this work contributes to the understanding of MPs and PAEs potential contamination profiles and sources in freshwater environments, and provides valuable information for future management decisions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Gold mining (GM) is a major source of metals and metalloids in rivers, causing severe environmental pollution and increasing the exposure risks to the residents of surrounding areas. Mining in Ecuadorian Amazonia has dramatically increased in recent years, but its impacts on Indigenous local populations that make use of rivers are still unknown. The aim of this study was to assess the risks to adults and children caused by the exposure to metals and metalloids in freshwater ecosystems contaminated with tailings released by GM activities in 11 sites of the upper Napo River basin, Ecuador. We selected a carcinogenic and a noncarcinogenic risk assessment method to estimate the hazard index (HI) and total cancer risk (TCR). The concentration of Ag, Al, As, Cd, Cu, Fe, Mn, Pb, Zn, B, and V in water and sediment samples was considered to assess the risks to human health. The calculated HI was 23-352 times greater than the acceptable limits in all sites for both children and adults. Mn and Fe were the main contributors (75% in water and 99% in sediment) to the total calculated risk based on the HI. The calculated TCR for children and adults exceeded approximately one to three times the permissible threshold in all sites. As and Pb contributed up to 93% of the total calculated risk based on TCR for both children and adults. This study demonstrates that the emission and mobilization of metals and metalloids caused by mining activities increase the risk to human health, to which we recommend further monitoring of freshwater contamination in the area and the implementation of preventive health management measures. Integr Environ Assess Manag 2023;19:706-716. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)., (© 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).)

• Geographical and anthropogenic factors co-contribute to the prevalence of MPs. • MPs in sediments have a higher vertical mobility than those in soils. • MPs communities in different compartments are significantly different. • Community similarities of MPs are highly correlated with geographical distance. • MPs transport to the ocean through water rather than riverine sediments and soils. Rivers have been recognized as major transport pathways for microplastics into the sea but large-scale quantitative data on the environmental fate of riverine microplastics remains limited, hindering proper risk assessment and development of regulatory measures. Microplastics in the whole Yangtze River Basin of China were systematically investigated by sampling the water, sediment, and soil. Microplastics were detected in all samples, with an average abundance of 1.27 items/L, 286.20 items/kg, and 338.09 items/kg for water, sediments, and soils, respectively, with polypropylene and polyethylene being the most abundant polymers. A generally increasing trend of microplastic abundance from upstream to downstream was identified, which were co-attributed by geographical and anthropogenic factors including elevation, longitude, distance from the nearest city, population density, urbanization rate, and land use. Microplastics in the sediments showed more prominent vertical migration than those in the soils, and the density and size of microplastics may be the key factors governing the migration of microplastics across different compartments. Community analysis showed that microplastics in different compartments were significantly different and highly correlated with geographical distance. Major cities at the middle and lower reaches were considered pivotal nodes of microplastic pollution in the Yangtze River Basin. Policy recommendations were also proposed towards better remediation of microplastic pollution involving riverine systems. [Display omitted] [ABSTRACT FROM AUTHOR]

The relative risk model (RRM) was applied to evaluate the ecological risk characterization of the freshwater ecosystems in China, from both overall and region-specific levels. Ten large-scale river basins (further broken into 15 risk regions) in China were chosen as the study objects; 10 sources, two habitats, and seven endpoints were identified as risk components. The results reveal the status of ecosystem conditions, key ecological risk issues, and the spatial heterogeneity of the freshwater ecosystems in China. The policy implications for the ecosystem-based water management contained in the results are discussed. The results obtained in this article provide a deeper understanding of the ecological risk characterization of the freshwater ecosystems in China, and aid in promoting the applications of the RRM as the tool for ecosystem-based water management. [ABSTRACT FROM PUBLISHER]

[Display omitted] • This study recorded the largest number of China's freshwater fish species in wilds. • The largest number of China's exotic and translocated species were reported. • Non-native species mainly belonged to three orders or families. • Native species were significantly different from non-native species in the traits. China's freshwater ecosystems are gradually invaded by an increasing number of non-native fish species. However, to date, some controversy about the number of native and non-native freshwater fish species in wild habitats and very limited information on ecological or biological traits mediating fish introduction success at a national scale have prevented the proposal and implementation of targeted conservation and management strategies. To address these urgent issues, first we compiled an up-to-date inventory of 1,797 fish species (1,597, 84, and 116 native, exotic (originating from outside China), and translocated (originating from within China) species, respectively) along with 13 traits encompassing various ecological and life-history strategies for each species, which is the most comprehensive freshwater fish database in China as we know. Here, we found that non-native species mainly belonged to three orders (Perciformes, Siluriformes, and Cypriniformes) and three families (Cichlidae, Cyprinidae, and Salmonidae). Native species were significantly (P < 0.001) different from both exotic and translocated species according to their quantitative traits, while no remarkable differences between exotic and translocated species were detected (P = 0.93). Specifically, G -tests of independence, Similarity Percentage Analysis (SIMPER), and Mann-Whitney-Wilcoxon rank sum tests showed that compared to native species, species with relatively higher vulnerability (intrinsic vulnerability of fishes to fishing), trophic level, and pectoral fin vertical position, but less resilience and lateral body shape were deemed as potential candidates for introduction and dispersal in China. [ABSTRACT FROM AUTHOR]

Ecological footprint (EF) analysis is an effective tool to assess ecosystem appropriation, but weaknesses still exist. In order to estimate a city's ecosystem appropriation, we made two modifications to EF: 1) including different types of freshwater area in the calculating framework; and 2) re-adjusting all equivalent factors in terms of different types of freshwater. The modifications are mainly concerned with changes in the composition of freshwater areas in EF analysis; that is, the proportion of aquaculture freshwater and tap freshwater. An assumption of 25 % of aquaculture freshwater was used to conduct a sensitivity test. It shows that variation of the proportion leads to different equivalent and yield factors for tap freshwater areas. The variations not only change the EF of freshwater but also the total EF. The modified EF calculation served to assess ecosystem appropriation in Jiangyin city in 1998. By comparing the original and the modified EF, it was found that the ecological deficit was larger (2.19 ha per capita) in the modified calculation than in the original (2.16 ha per capita). The original calculation is an underestimate because direct consumption of freshwater was not fully included in its calculating framework. From the modified calculation, the EF for different categories of ecosystems decreased, from fossil energy land, arable land and pasture to built-up areas, which together occupy about 97.58% of the total EF. Fossil energy land occupied 68.55% of the total, while freshwater areas took only 0.62%. The main ecological deficits were from fossil energy land, arable land, pasture and marine areas. Ecological supply is lacking within Jiangyin and relies on ecosystems outside the city to survive. Ecosystem management is indispensable to optimise the efficiency of ecosystem use and to expand the biological capacity of the city. The modified EF could provide a more reasonable instrument in policy-making and implementing sustainable management of freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems provide a host of services to humanity. These services are now rapidly being lost, not least because of the inability of making the impacts measurable. To overcome this obstacle, assessment frameworks for freshwater ecosystem services are needed. A simple water equivalent framework to assess the ecological services provided by freshwater ecosystems was developed in this study. It translated the occupation of freshwater ecosystem services into biologically freshwater volumes and then compares this consumption to the freshwater throughput, that is, the ecological capacity available in this region. In this way, we use the example of Yangzhou Prefecture, to account the main categories of human occupation of water ecosystem services. The result showed that there is a huge gap between the consumption and the supply of freshwater ecosystem services. This must encourage local government to make land-use and water management decisions both economically rational and environmentally sound. [ABSTRACT FROM AUTHOR]

The habitat and feeding environment of freshwater fish in freshwater lakes have been destroyed, with the problem of miniaturization and simplification of catches being serious. An artificial reef is an effective technical measure to protect and proliferate offshore fishery resources, but little research has been conducted on its application in freshwater lakes. A small artificial reef for freshwater lakes was designed according to the water depth of the lake and the habits of benthic fish. The artificial reef is composed of biomass modules, each of which is 900 × 120 mm. The community structure of phytoplankton around the artificial reef and its adjacent waters was studied. The results showed that 77 species from seven phyla were identified, with a high number of species from the Chlorophyceae. In terms of density composition, the density of cyanobacteria decreased month by month, while the phylum Chlorophyta and Cryptophyta increased first and then decreased. As for biomass composition, Chlorophyta and Cryptophyta increased first and then decreased. RDA analysis showed that water temperature, dissolved oxygen, and total phosphorus were the main influencing factors. To sum up, the artificial reef can improve the algae phase in the surrounding water column, inhibit the growth and reproduction of cyanobacteria to a certain extent, and have a significant enrichment and promotion effect on diatoms. Artificial fish reef affects the phytoplankton community structure of the surrounding water bodies mainly through the absorption of phosphorus nutrients. Artificial reefs can be popularized and applied in freshwater lakes to provide foraging and shelter for benthic fish in the lake. [ABSTRACT FROM AUTHOR]