Alteration of freshwater ecosystem services under global change - A review focusing on the Po River basin (Italy) and the Red River basin (Vietnam)

Sustainable Ecosystem Services of a Time-Honored Artificial River Ecosystem-Enlightenments from the Carp Brook, in Northern Fujian Province, China

Building a harmonious relationship between human society and river ecosystems has attracted much attention from both government officials and the academy community. Based on the perspective of social-ecological systems (SES), taking the Carp Brook (located in northern Fujian Province, China) as an example, the construction and maintenance of a time-honored artificial river ecosystem was investigated, and its ecosystem services were analyzed. Findings show that the Carp Brook was constructed through a series of ecological engineering, including a transformation of the river channel, building a stable habitat, and breeding carps. The carps have been protected effectively by some folk customs, such as village regulations and folk belief. Meanwhile, the water quality has been maintained through some engineering and institutional measures, which were completed by the local government and villagers. Furthermore, some cultural elements with local characteristics have been formed during the long years of coexistence between human society and the Carp Brook. Based on a healthy ecosystem and abundant culture elements, the Carp Brook provided continuous ecosystem services to human society for more than 800 years, including regulation services (e.g., water purification and flood control) and cultural services (e.g., tourism, research and education, inspiration). Major enlightenments from the Carp Brook are: (a) the Chinese traditional view of nature is important for the construction and maintenance of an artificial ecosystem; (b) traditional folk customs have a strong binding force regarding the protection of the ecosystem; and (c) the choice between material and immaterial services should be made carefully.

Spatial and Seasonal Assessment of Water Quality in the Lobo Stream River Basin, Brazil Using Multivariate Statistical Techniques

In view of the complexity of the processes associated to water quality, this study objective is to identify the main factors related to spatial and seasonal variability in water courses of the Lobo Stream River Basin. To this, multivariate statistical techniques were used. Data collection for water quality and streamflow variables were carried out monthly, from May 2018 to April 2019, at 10 monitoring points along basin's tributaries. The results show that, during the dry season, the main causes for water quality decrease are related to erosion process on the river margins, which is intensified by inadequate handling in livestock activities in some monitoring points. In the rainy season, the main causes are related to soil leaching in agricultural areas that increases the nitrogen compounds concentration and reduces water quality. However, in addition to this, it was noted that regardless the environmental conditions, the most impactful factor is the point pollution from the effluent discharge of Itirapina City sewage treatment plant, responsible for nutrient concentration increase, organic contamination, OD reduction, and, consequently, water quality deterioration. With this, the study shows how multivariate statistical analysis enables more relevant evaluation of water quality data variability and supports further studies in the basin.

Effects of excessive water extraction on groundwater ecosystem services: Vulnerability assessments using biophysical approaches

In this research, a systematic, integrated framework was developed to evaluate the biophysical state and vulnerability intensity of groundwater supply ecosystem service (GSES) regarding excessive groundwater withdrawal in the Mashhad plain located in the northeastern of Khorasan Razavi province in Iran. At first, following an indexing approach, the biophysical aspects of the ecosystem, including capacity, flow, and the benefits of GSES, were analyzed. Afterward, the relationship between the capacity and flow ecosystem service (ES) was assessed to identify ecosystem's sustainability status. Furthermore, GSES stability was spatially shown. Finally, GSES vulnerability and its associated ESs was assessed based on 3D model of vulnerability via indexing three components of exposure, sensitivity, and adaptive capacity. The final map spatially indicated the zoning of groundwater ecosystem services' vulnerability intensity in Mashhad Plain. The outcomes indicate a high and very high vulnerability in more than 35% of studying area. The results indicate that about 18%, 30%, and 15% of studying land show moderate, low, and no vulnerability, respectively. Finally, it was observed that due to groundwater's over-extraction, supplying the aquifer ecosystem services was disrupted. This method can be used as a solution for the sustainable management of groundwater resources, especially in the arid and semi-arid countries facing the depletion of water resources.

Aquatic plants and ecotoxicological assessment in freshwater ecosystems: a review

This paper reviews the current state-of-the-art, limitations, critical issues, and new directions in freshwater plant ecotoxicology. We selected peer-reviewed studies using relevant databases and for each (1) publication year, (2) test plant species, (3) reference plant group (microalgae, macroalgae, bryophytes, pteridophytes, flowering plants), (4) toxicant tested (heavy metal, pharmaceutical product, hydrocarbon, pesticide, surfactant, plastic), (5) experiment site (laboratory, field), and (6) toxicant exposure duration. Although aquatic plant organisms play a key role in the functioning of freshwater ecosystems, mainly linked to their primary productivity, their use as biological models in ecotoxicological tests was limited if compared to animals. Also, toxicant effects on freshwater plants were scarcely investigated and limited to studies on microalgae (80%), or only to a certain number of recurrent species (Pseudokirchneriella subcapitata, Chlorella vulgaris, Lemna minor, Myriophyllum spicatum). The most widely tested toxicants on plants were heavy metals (74%), followed by pharmaceutical products and hydrocarbons (7%), while the most commonly utilized endpoints in tests were plant growth inhibition, variations in dry or fresh weight, morpho-structural alterations, chlorosis, and/or necrosis. The main critical issues emerged from plant-based ecotoxicological tests were the narrow range of species and endpoints considered, the lack of environmental relevance, the excessively short exposure times, and the culture media potentially reacting with toxicants. Proposals to overcome these issues are discussed.

Modulation of the intestinal barrier adaptive functions in red-eared slider (Trachemys scripta elegans) invading brackish waters

Globally, the increase in sea levels is leading to salinization of freshwater, which might influence the freshwater organisms such as red-eared slider, Trachemys scripta elegans. The turtle can invade brackish water environments, in which it must deal with elevated salinity in the gastrointestinal tract that could impact the intestinal function. The intestinal barrier provides a front-line of organismal defense against the chemical and biological environmental insults. In this study, the adaptive functions of the intestinal barrier including intestinal histomorphology, genes involved in intestinal barrier functions, and the intestinal micro-ecosystem were analyzed in the turtles exposed to freshwater (S0), 5‰ salinity (S5) and 15‰ salinity (S15) water for 30 days. The results showed that the intestine of T. s. elegans maintained normal histomorphological structure in the S5 group, whereas the villus height, crypt depth and the number of goblet cells in the S15 group were lower than that in the S5 and S0 groups. In addition, the relative expression levels of epithelial tight junction-related genes and intestinal immune-related genes in the gut were significantly upregulated in the S15 group, compared to the freshwater group. Mucin-2 gene expression was downregulated, but mucin-1 transcript levels were upregulated in salinity-treated groups. Furthermore, the abundances of phylum Proteobacteria, and genera Morganella and Aeromonas in the intestine were particularly enhanced in the S15 group than the S0 and S5 groups. Taken together, these results indicate that the intestinal barrier plays a protective role in T. s. elegans adaptation to brackish water environments. Our results provide a perspective on the evolution of salinity tolerance and help to evaluate the potential danger of the turtle to other species, and understand the challenges that other species must meet with rising sea levels.

Research on ecosystem services of water conservation and soil retention: a bibliometric analysis

Water conservation and soil retention are two essential regulating services that are closely related, and their relationship might produce synergies or trade-offs. Distinguishing the current status and evolution of research in this field could provide a scientific foundation for subsequent research. "Water conservation" and "soil retention" were selected as keywords for a search of Web of Science for publications during 1976-2018. A total of 4489 periodical articles were obtained. Using bibliometric and social network analysis tools, the scientific output performance, national research contributions, potential hot topics, and connections between keywords and the levels of cooperation between countries at different stages were explored to reveal the related development trends. The results showed that the literature on water conservation and soil retention increased rapidly, especially after 2008. The USA, China, and India were the most productive countries, and the USA, the UK, and Canada were the most influential countries regarding international cooperation. Agriculture, water resource utilization, water-soil erosion, and ecosystem services were closely related topics, and the connections between these topics have increased since 1998. In addition to sustainability, the response of water conservation and soil retention to global environmental change, such as water resource management, land use, and land conservation, are potential emerging research hotspots.

A Scoring Matrix Method for Integrated Evaluation of Water-Related Ecosystem Services Provided by Urban Parks

Increasing urbanization, landscape conversion, and resource consumption represent the most important, visible and irreversible human-induced actions on Earth. As a consequence, nowadays it is of seminal importance to understand and assess how anthropic pressures are related to the provision of ecosystem services (ES). This paper focuses on urban parks and their provision of water-induced ecosystem services (WES) connected to urban hydrologic cycle. The study uses a broad holistic approach to comprehensively understand the links between anthropic pressures and WES production. With the help of biological, chemical, and physical indicators collected in publicly available databases a scoring matrix was created. The method was applied to two different parks in Turin (Italy), the Arrivore Park and the Michelotti Park. The matrices reveal that anthropic pressures are marked, and the most affected WES are habitat maintenance, recreational services, and the provision of drinkable and non-drinkable water. The hydromorphological alterations are the anthropogenic pressures most strongly present in both parks. More specifically, in the Arrivore Park urbanization represents one of the most important pressures while the main pressures in the Michelotti Park are water abstraction for industrial and agricultural use and point source pollution. This study makes a major contribution to research on WES assessment by demonstrating the possibility to understand and to assess the impact of anthropic pressures. Moreover, the proposed matrix method provides an easy tool to support policymakers, public administrations, and private companies within sustainable urban planning.

Functional response of fish communities in a multistressed freshwater world

Freshwater fish communities are impacted by multiple pressures, determining loss of functional diversity and redundancy. Our aim was to disentangle the roles and relevancies of different pressures in shaping fish communities in small streams of the Po plain (North Italy). Long term trend (1998-2018) of functional diversity of 31 fish communities was assessed and modeled in respect to three potential pressures: temperature increase, intensity of exotic fish invasion, and habitat quality degradation. Ecological traits mostly influenced by the pressures were also identified. Reduction of functional richness mostly due to local extinction or contraction of cold adapted predators, such as salmonids, was linked to increasing temperatures. Warming probably also led to a shift of generalist and dominant species, which became more abundant in streams hosting mixed communities of salmonids and cyprinids, and determined the increase of functional dispersion and uniqueness. Reduction of functional redundancy and increasing functional dispersion were both also related to the introduction of new ecological traits brought by expanding exotic species. Low functional overlap was found among native and exotic species, indicating that the invasion process was mainly controlled by competitive interactions and/or resource opportunism. Functional response to habitat quality was not clearly evident. In conclusion, the impact of temperature increase and exotic species on fish functional diversity was effective, idiosyncratic and mediated by the scale of analysis and by the intensity of pressures.

Physiological Profiling and Functional Diversity of Groundwater Microbial Communities in a Municipal Solid Waste Landfill Area

The disposal of municipal solid wastes in landfills represents a major threat for aquifer environments at the global scale. The aim of this study was to explore how groundwater geochemical characteristics can influence the microbial community functioning and the potential degradation patterns of selected organic substrates in response to different levels of landfill-induced alterations. Groundwaters collected from a landfill area were monitored by assessing major physical-chemical parameters and the microbiological contamination levels (total coliforms and fecal indicators—Colilert-18). The aquatic microbial community was further characterized by flow cytometry and Biolog EcoPlatesTM assay. Three groundwater conditions (i.e., pristine, mixed, and altered) were identified according to their distinct geochemical profiles. The altered groundwaters showed relatively higher values of organic matter concentration and total cell counts, along with the presence of fecal indicator bacteria, in comparison to samples from pristine and mixed conditions. The kinetic profiles of the Biolog substrate degradation showed that the microbial community thriving in altered conditions was relatively more efficient in metabolizing a larger number of organic substrates, including those with complex molecular structures. We concluded that the assessment of physiological profiling and functional diversity at the microbial community level could represent a supportive tool to understand the potential consequences of the organic contamination of impacted aquifers, thus complementing the current strategies for groundwater management.

An Optimal Allocation Model for Large Complex Water Resources System Considering Water supply and Ecological Needs

Water resources are very important to support the socio-economic development and maintain environmental health, which is a typical issue in water resources management. In this study, we developed an optimal allocation model for a large complex system of water resources by considering both water supply and river ecological benefits. The water supply benefit is defined as the minimum water deficit for different water users, while the ecological benefit involves making the reservoir release as close as possible to the natural streamflow. To solve this problem, the combination of decomposition-coordination (DC) and discrete differential dynamic programming (DDDP) methods were proposed. The proposed methods first decomposed a large system with multi-objective programming into subsystems, and the optimal solution of each subsystem was accomplished by the DDDP method to solve the system efficiently. Then the subsystems’ solutions were coordinated to figure out the near global optimal solution. The proposed models were tested in the Lingui and Yongfu County, Guilin City in China. Results show that the optimal reservoir release is close to the natural flow regime and there is a slight water deficit ratio in both level years. The water supply objective is more sensitive to the system model compared with the ecological objective, and the result of water allocation is optimized when the reservoir release is as close as possible to the natural flow based on the minimum water deficit. The proposed system model could facilitate sustainable water use and provide technical support for water resources management in economic development.