Natural Wetlands Research Articles

Removal characteristics of microplastics in sewage flowing through a long-term operation surface flow wetland

Microplastics (MPs) in sewage pose significant threats to aquatic system. Surface flow wetland (SFW) is a common natural wetland type, and is also used as a cheap and easy-to-build sewage treatment system for small and scattered settlements. However, seasonal variation patterns of MPs in sewage removed by SFW are still limited. Therefore, a field investigation was conducted in an SFW that has been operated for 17 years. The concentration of microplastics in the influent of the SFW (CMPs, in) ranged from 56 ± 6 to 250 ± 14 items L−1. The dominant plastic types were fibers and polyethylene terephthalate (PET). CMPs, in were high in summer and winter, significantly related to the seasonal dressing habits. The removal efficiencies of MPs in SFW were 48.03–92.32 % in different seasons, and the mechanisms of MP removal were different with traditional pollutants. Before flowing out occasionally or by heavy precipitation, MPs were primarily trapped in the SFW and underwent certain oxidation. Simulation experiments demonstrated that 47.5–92.9 % of MPs would be trapped in the SFW, and plants would significantly enhance the trapping capacities. This study sheds light on the seasonal variation characteristics and patterns of MPs in actual sewage, and clarifies the fate of MPs in a long-term operation SFW.

Vegetation Growth Monitoring in Jiaozhou Bay Coastal Wetland Based on Multi-Source Remote Sensing Data

Jiaozhou Bay coastal wetland, located in the mouth of the Dagu River, is an estuary wetland. In this wetland seawater blends with freshwater. It is a rare type of national wetland, a unique ecosystem on earth. It is of great research value, but there are few articles conducting multi-indicator studies about Jiaozhou Bay coastal wetland ecosystem. This paper helps to formulate wetland conservation measures comprehensively through multi-source remote sensing monitoring. Based on NDVI, FVC, LAI, NPP and the spatial distribution changes of land use, this paper is a synthetical exploration of the vegetation growth of Jiaozhou Bay coastal wetland. The results show that: 1) From 2013 to 2019, NDVI, LAI and NPP indices rose to varying degrees in the coastal wetlands of Jiaozhou Bay. FVC showed a broad downward trend, and its indicators are declining in the north-central region; 2) The major land types are impervious surface and grassland, where the decrease proportion of grassland is the largest, and the increase proportion of impervious surface is the largest in the study area; 3) Analytical results demonstrate that the overall vegetation situation of Jiaozhou Bay coastal wetland improved on the whole, but with local deterioration. So, ecological protection measures in the study area have begun to bear fruit.

An evaluation of spatial and seasonal distributions of dissolved trace metals in the water of the natural wetlands

The spatial and temporal distributions of trace metals in dissolved forms mainly result from anthropogenic and lithogenic contributions. Surface water samples (∼0.5 m) were collected monthly at respective stations from Setiu Wetland. In this study, the behaviour of trace metals in the dissolved phases along the water column from sampling sites in the Setiu Wetland, Malaysia was investigated. In addition, dissolved organic carbon (DOC) and physical parameters such as salinity, temperature, pH and dissolved oxygen (DO) of the surface water were measured in order to evaluate the relationship between trace metals fractionation with different water quality parameters. Size fractionation study of dissolved trace metals using ultrafiltration technique were also carried out and analysed using inductively coupled plasma mass spectrometry (ICP-MS). Correlation of trace metals with other measured parameters was made to furthermore understand the dynamics of trace metals and its fractionated components in this area. The concentration of dissolved trace metals was in the range of 0.001–0.16 μg/L for Cd, 0.12–2.81 μg/L for Cu, 0.01–1.84 μg/L for Pb, 3–17 μg/L for Fe and 1–34 μg/L for Zn, suggesting the input of anthropogenic sources for trace metals such as municipal, industrial, agricultural and domestic discharge. The periodic monitoring and evaluation of trace metals in wetlands and protected tropical areas is highly recommended.

Microbial-driven carbon fixation in natural wetland.

With the development of global industrialization, carbon neutrality has become an issue that we must be paid attention to. Microorganisms not only have an important impact on the carbon chemical cycle between the Earth's biosphere and biogeography but also play a key role in maintaining the global organic carbon balance. Wetlands are the main reservoir of organic carbon in the mainland of China, and wetland carbon sinks are indispensable for China to achieve the goal of "dual carbon," and China has taken the consolidation and improvement of wetland carbon sink capacity as an important part of the carbon peaking action plan. As a unique low-latitude, high-altitude seasonal plateau wetland in China, Napahai shows high research value. However, the role of microbes in maintaining dissolved organic carbon balance in this area has not been reported. In the study, six carbon fixation genes, accA, aclB, acsA, acsB, cbbL, and rbcL, were analyzed based on metagenomics to elucidate the rich genetic diversity, uniqueness and differences in the Napahai plateau wetland. It was found that the microbial diversity in the Napahai plateau wetland was different from other habitats. In addition, the aclB gene, a rare taxon with high genetic diversity and rich species in the Napahai plateau wetland, played a key role in the microbial metabolic pathway. Finally, the construction of a metabolic pathway through the Kyoto encyclopedia for genes and genomes revealed the contribution of microbes to carbon fixation and the role of microbes in maintaining the organic carbon balance of the Napahai plateau wetland.

Coastal wetland restoration framework based on hydrogeomorphic units of the coastal wetland of Yancheng, China

Effective implementation of restoration projects is essential to solving the degradation of coastal wetlands. Due to the lack of systematic guidance or unsuitable engineering measures, some coastal wetland restoration projects have suffered from lower-than-expected results and poor sustainability. Therefore, it is necessary to construct a regional-scale wetland restoration framework from a macro perspective prior to project implementation, which can guide pre-study and follow-up restoration practices. In this study, the hydrogeomorphic units (HGUs) of Yancheng coastal wetlands were delineated according to the regional hydrogeomorphic conditions, and the changes in land use/cover and hydrological connectivity of each HGU from 1980 to 2019 were analyzed. The results showed that the area of natural wetlands in the study area declined rapidly, with a decline of 48.38%, and was mainly converted to aquaculture ponds or farmland during the 40 years. The structural complexity and transport capacity of tidal creeks decreased significantly, which indicated that the hydrological connectivity decreased. The main problems of degradation in the region were the reduction of large areas of natural wetlands, the rapid expansion of exotic species, and the decline in hydrological connectivity, etc. Combining the degradation problems and the restoration objectives, feasible strategies and methods were selected for different types of HGUs from both active and passive restoration categories, thus forming a coastal wetland restoration framework for the Yancheng coastal wetlands based on HGUs. This study takes regional hydrogeomorphology as the antecedent context condition, and the idea of a systematic restoration framework constructed by combining landscape perspectives can provide scientific support for wetland restoration practice.

Assessment of eco-environmental quality changes and spatial heterogeneity in the Yellow River Delta based on the remote sensing ecological index and geo-detector model

As the youngest wetland ecosystem, the Yellow River Delta (YRD) has well-structured and species-rich natural wetland resources. However, its eco-environment is very fragile due to the existence of long-term natural and man-made pressures. Along these lines, the ecological quality assessment is considered of great significance to the sustainable development of the YRD. More specifically, spatial differentiation is regarded as the spatial manifestation of both natural and anthropogenic pressure on the eco-environment quality (EEQ). From the spatial heterogeneity analysis, the driving factors can be revealed and a reliable basis for environmental governance in this region can be provided. To the end, based on the Google Earth Engine (GEE) cloud platform, a remote sensing ecological index (RSEI) was developed here to quickly, objectively, and efficiently evaluate the EEQ in the YRD. Moreover, the spatial heterogeneity of the eco-environmental quality and the interaction among the driving factors in this region were quantitatively analysed by using the geo-detector model (GDM). The results indicated that (1) the EEQ of the YRD exhibited a slightly improved trend from 2013 to 2021; (2) the overall EEQ remained at an intermediate level, and at an intermediate level or above in 80% of the study area; (3) the interaction of multiple both factors affect the EEQ of the YRD, among which land-use/cover is considered the most significant factor affecting the spatial differentiation of the EEQ. It is imperative to consider the multiple factors in a comprehensive manner to realize the green economy of sustainable development in the YRD, while the role of humans in improving the ecological environment construction should be strengthened.

Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities

Documenting biodiversity, species occurrence, and species status require reliable monitoring techniques, but the complex life history and cryptic behavior of many anurans create challenges for conventional monitoring approaches. Environmental DNA (eDNA) surveys are a promising alternative (or complement) to conventional anuran monitoring, but their relative success has not been fully tested. We assessed the comparative efficacy of targeted eDNA detection via quantitative PCR (qPCR) and three conventional amphibian survey methods (visual encounter, breeding call, and larval dipnet surveys) for detecting nine anuran species in natural wetlands in southern Ontario, Canada. Our analyses revealed that all assessment methods yielded imperfect detection, with visual encounter and eDNA surveys detecting the greatest species richness and eDNA surveys requiring the fewest sampling events. Amphibian community composition results differed among survey methods and sampling events, and detection efficacy was markedly variable, with some species requiring two to three methods to maximize detection success. Notably, two relatively terrestrial species (Anaxyrus americanusandHyla versicolor) had relatively low and seasonally variable eDNA detection rates, suggesting that species-specific ecology likely affects eDNA presence or detection. These findings suggest that optimized monitoring for complex anuran communities may require application of multiple monitoring methods, which may need to be tailored to individual target species or communities.

Ecosystem health assessment and comparison of natural and constructed wetlands in the arid zone of northwest China

Wetlands in the arid zone of northwest China have ecological values such as climate regulation, water conservation, and biodiversity maintenance. However, in the context of global warming and economic development, the degree of natural and human interference in the wetlands has been increasing, and wetland health problems are becoming increasingly severe. The current comparative research on the ecosystem health evaluation of natural and constructed wetlands and their sustainable development in the arid zone of northwest China is not perfect, so we selected the natural (Dunhuang Xihu Wetland) and constructed wetlands (Suzhou District Wetland) as research objects. The ecosystem health evaluation system has been developed from 5 levels of the drive, pressure, state, impact, and response (DPSIR). The ecological health status and impact factors were evaluated for the two wetlands using socioeconomic data combined with remote sensing technology from 2000 to 2019. The results showed that 1) the ecological health of natural and constructed wetlands was in a medium healthy state, and the ecological health values of the wetlands showed a trend of decreasing and then increasing from 2000 to 2019, with 2005 as the turning point. The ecological health status of natural wetlands (0.46) was better than that of constructed wetlands (0.42). 2) The main reasons for the degradation of constructed wetlands (-3.20%) were the urban population expansion and blind agricultural reclamation of wetlands, while the degradation of natural wetlands (-6.45%) was dominated by extreme climatic conditions and overuse of water resources. These results provide case support and a theoretical basis for the conservation management and sustainable development of wetland ecosystems in the arid zone.

Water Management to Cope with the Effects of Climate Change Best practices in Water Management at Wageningen University & Research

Wageningen University & Research studies the causes of heavy rainfall and droughts and is looking for solutions to these phenomena [1]. For example, green spaces in the urban environment ensure that water can be drained into the ground. Storage of water is also important, because not only the number of heavy rains is increasing, also there are longer periods of drought. On WUR Campus, these principles of coping with flooding and drought are applied. There is a sizeable area of green space which serves as a groundwater discharge area. The large ponds on campus are used to collect and store excess surface water. During droughts the ponds retain water on campus. In two campus buildings, rain is harvested for flushing toilets and watering inner gardens. The rainwater is harvested from rooftops and stored in underground water tanks. A natural garden was laid out in 1998, and four years ago a natural wetland garden was added to the campus.The effects of climate change, such as droughts and rising sea water levels affect freshwater supplies, which makes efficient use of water increasingly important. WUR aims to reduce consumption of tap water every year, by increasing water use efficiency and switching to sources other than tap water.

Conversion of natural coastal wetlands to mariculture ponds dramatically decreased methane production by reducing substrate availability

Coastal wetlands are increasingly being converted into aquaculture ponds to meet growing global demand for fish protein. Coastal wetlands conversion has been predicted to result in significant carbon (C) emissions; however, a mechanistic understanding of the effects of coastal wetland conversion on soil’s capacity to produce greenhouse gases remains lacking. Here, integrated biogeochemical investigations on methanogenic substrates, community structures, and activities were conducted in a coastal Spartina alterniflora saltmarsh and three saltmarsh-converted mariculture ponds aged 6, 13, and 20 years. Saltmarsh conversion into mariculture ponds decreased CH4 production potential from 353 to 16.3–78.3 µg CH4 kg−1 d−1. The concentrations of dissolved organic C and non-competitive methanogenic substrate, trimethylamine, were reduced by 84.8% and 79.7%, respectively, whereas methanogens abundance decreased by 43.7%, probably due to the decreased C input following conversion. Among the ponds, CH4 production potential, methanogenic substrates (acetate and trimethylamine), and methanogen abundance decreased with conversion chronosequence. However, the dominant methanogen group did not shift after land conversion, and the potential methylamine-utilizing Methanosarcinaceae accounted for 86.5% and 85.3–89.7% of the total populations in the S. alterniflora saltmarsh and mariculture ponds, respectively, implying that methylotrophic methanogenesis was the predominant pathway of CH4 production in both ecosystems. The results indicated that the conversion of natural coastal saltmarsh to mariculture ponds decreased CH4 production by reducing substrate availability and methanogen abundance, and CH4 production potential in mariculture ponds was more efficiently suppressed with conversion chronosequence.

Landscape Pattern Changes and Climate Response in Nagqu Hangcuo National Wetland Park in the Tibetan Plateau

Wetlands are vital ecosystems in the Tibetan Plateau that play a crucial role in water conservation, flood storage, and biodiversity maintenance. They are sensitive to climate change and typically have high ecological and environmental quality levels due to minimal human disturbance. This study aimed to quantify landscape pattern changes within the Nagqu Hangcuo National Wetland Park (NNWP) and identify the impact of climate on wetland change. Using remote sensing data from six periods (1990, 1995, 2000, 2005, 2010, and 2015), dynamic change analysis, landscape pattern analysis, and correlation analysis were employed to determine the evolutionary features of the wetland landscape and explore their relationship with climatic factors. The results showed that the total wetland area increased from 15.11 km2 in 1990 to 15.23 km2 in 2015. The meadow area increased the most among landscape types, primarily converted from swamps. Over 25 years, the fragmentation of the NNWP’s landscape increased while diversity decreased and its shape became more complex. Meadows were more sensitive to climatic factors than other landscape types, with correlation coefficients between wetland separation and sunshine duration being more significant than other climatic factors. Therefore, it is imperative to monitor landscape pattern changes and the effects of climate change to better protect wetland parks through long-term planning, suitable mechanisms, and advanced technology.

Wise use of coastal wetlands: 10-year reclamation vs. 3-year eco-governance in the Tiaozini Wetland, Jiangsu, China

Coastal wetlands provide extensive ecological services for life on Earth but are facing rapid global disappearance influenced by human activities and climate change. From 1984 to 2018, approximately 28% of the natural coastal wetlands in China were lost due to seawater intrusion, reduced sediment acquisition, urbanization, and reclamation. Tiaozini wetland used to be reclaimed during 2010-2019, and quickly shifted for conservation with less than 3 years. We analyzed 3 years of top-down eco-governance and bottom-up activities in Tiaozini, one of the typical wetlands with wise use instead of reclamation. Collaboration of stakeholders, such as the management company, local residents, tourists, scientific committees, NGOs, and media, facilitated the wise use of Tiaozini wetland as a successvie way towards eco-governance, including public participation and environmental education. Adaptive management, ecosystem-based management, and natural-based solutions play very important roles in eco-governance from both bottom-up and top-down approaches. Results showed that 3-year eco-governance induced great achievements in both biodiversity conservation and ecotourism development, which outweighs the 10-year reclamation for coastal wetlands exploitation.

Coupling Biodiversity and Human Pressures to Indicate Conservation Priorities for Threatened Waterfowl Species: A Case in the Henan Yellow River Wetland National Nature Reserve

Following severe anthropogenic pressure from rapid economic development, wetland biodiversity is now decreasing alarmingly, thus leading to adverse effects. Protected areas (PAs) can be crucial conservation tools to secure wetland biodiversity. However, whether these PAs exhibit high conservation efficiency in buffering wildlife and habitats from human pressures needs to be understood. Given their sensitivity to habitat quality and regional resource changes, threatened waterfowl could be suitable wetland ecosystem indicators. This study examined the conservation effectiveness of Henan Yellow River Wetland National Nature Reserve (HYRWNNR), which is a crucial region on the East Asia–Australia route for global bird migration. We performed Maximum Entropy (MaxEnt) modeling based on field survey data of the 19 threatened waterfowl species, and Human Impact Index (HII) was further mapped with waterfowls distribution to identify the conservation gap and priorities of the HYRWNNR. The results indicated that threatened waterfowl distribution were affected by both environmental factors and human pressure, and a conservation gap existed in the HYRWNNR. Two conservation scenarios were generated based on the spatial pattern of conservation priorities, and their corresponding management strategies were suggested. This study identifies conservation priorities from a novel perspective by synthesizing habitat suitability and human pressure, which can present basic information regarding the HYRWNNR management while supporting waterfowl conservation planning, ultimately promoting wetland habitats sustainability.

Characterization of microbial community and antibiotic resistome in intra urban water, Wenzhou China.

The present study investigated the water quality index, microbial composition and antimicrobial resistance genes in urban water habitats. Combined chemicals testing, metagenomic analyses and qualitative PCR (qPCR) were conducted on 20 locations, including rivers from hospital surrounds (n = 7), community surrounds (n = 7), and natural wetlands (n = 6). Results showed that the indexes of total nitrogen, phosphorus, and ammonia nitrogen of hospital waters were 2-3 folds high than that of water from wetlands. Bioinformatics analysis revealed a total of 1,594 bacterial species from 479 genera from the three groups of water samples. The hospital-related samples had the greatest number of unique genera, followed by those from wetlands and communities. The hospital-related samples contained a large number of bacteria associated with the gut microbiome, including Alistipes, Prevotella, Klebsiella, Escherichia, Bacteroides, and Faecalibacterium, which were all significantly enriched compared to samples from the wetlands. Nevertheless, the wetland waters enriched bacteria from Nanopelagicus, Mycolicibacterium and Gemmatimonas, which are typically associated with aquatic environments. The presence of antimicrobial resistance genes (ARGs) that were associated with different species origins in each water sample was observed. The majority of ARGs from hospital-related samples were carried by bacteria from Acinetobacter, Aeromonas and various genera from Enterobacteriaceae, which each was associated with multiple ARGs. In contrast, the ARGs that were exclusively in samples from communities and wetlands were carried by species that encoded only 1 to 2 ARGs each and were not normally associated with human infections. The qPCR showed that water samples of hospital surrounds had higher concentrations of intI1 and antimicrobial resistance genes such as tetA, ermA, ermB, qnrB, sul1, sul2 and other beta-lactam genes. Further genes of functional metabolism reported that the enrichment of genes associated with the degradation/utilization of nitrate and organic phosphodiester were detected in water samples around hospitals and communities compared to those from wetlands. Finally, correlations between the water quality indicators and the number of ARGs were evaluated. The presence of total nitrogen, phosphorus, and ammonia nitrogen were significantly correlated with the presence of ermA and sul1. Furthermore, intI1 exhibited a significant correlation with ermB, sul1, and blaSHV, indicating a prevalence of ARGs in urban water environments might be due to the integron intI1's diffusion-promoting effect. However, the high abundance of ARGs was limited to the waters around the hospital, and we did not observe the geographical transfer of ARGs along with the river flow. This may be related to water purifying capacity of natural riverine wetlands. Taken together, continued surveillance is required to assess the risk of bacterial horizontal transmission and its potential impact on public health in the current region.

Bacterial Communities Associated with the Roots of Typha spp. and Its Relationship in Phytoremediation Processes.

Heavy metal pollution is a severe concern worldwide, owing to its harmful effects on ecosystems. Phytoremediation has been applied to remove heavy metals from water, soils, and sediments by using plants and associated microorganisms to restore contaminated sites. The Typha genus is one of the most important genera used in phytoremediation strategies because of its rapid growth rate, high biomass production, and the accumulation of heavy metals in its roots. Plant growth-promoting rhizobacteria have attracted much attention because they exert biochemical activities that improve plant growth, tolerance, and the accumulation of heavy metals in plant tissues. Because of their beneficial effects on plants, some studies have identified bacterial communities associated with the roots of Typha species growing in the presence of heavy metals. This review describes in detail the phytoremediation process and highlights the application of Typha species. Then, it describes bacterial communities associated with roots of Typha growing in natural ecosystems and wetlands contaminated with heavy metals. Data indicated that bacteria from the phylum Proteobacteria are the primary colonizers of the rhizosphere and root-endosphere of Typha species growing in contaminated and non-contaminated environments. Proteobacteria include bacteria that can grow in different environments due to their ability to use various carbon sources. Some bacterial species exert biochemical activities that contribute to plant growth and tolerance to heavy metals and enhance phytoremediation.

Understanding the role of surface runoff in potential flood inundation in the Kashmir valley, Western Himalayas

In the present study, direct runoff and Total runoff were estimated at temporal scales (2000–2018) focusing on flood potential in the catchments of Kashmir valley. The valley is recurrently prone to catastrophic floods with increased Total runoff frequency in recent decades (post-2010 periods). LANDSAT ETM+ satellite image based land use/land cover mapping exhibited the dominance of vegetation cover (46%) primarily in the peripheral hilly regions, in contrast to agricultural land (29%) and built-up (1.6%) in the elongated valley region. The high anomalous rainfall (>500 mm) in most of the catchments during 2014–2018 caused an increased runoff apparently leading to catastrophic floods inundation (as observed in 2014 with accumulated rainfall of 713 mm and cumulative Total Runoff of 55 LCM). A higher contribution towards Total Runoff in northern catchments (>56%) exhibited higher susceptibility to flood inundation as compared to the southern catchments (<42%). The study highlighted a high vulnerability in the large proportion of built-up land (148 km2) within close proximity to Jhelum river and below 1560m elevation range due to the erratic rainfall induced runoff floods. The insignificant proportion of built-up led to less contribution towards the high runoff yet increases the severity of runoff and flood inundation due to high imperviousness. The rapid built-up growth coupled with deterioration of natural wetlands in the urban-rural fringe increased the impact of catastrophic flood manifolds. The study provided a regional and comprehensive runoff assessment that can be utilized to develop adequate flood control measures at the catchment level in the valley.

Site-specific spatiotemporal occurrence and molecular congener distributions of naphthenic acids in Athabasca oil sands wetlands of Alberta, Canada

The Athabasca oil sands region (AOSR) of Alberta, Canada is notable for its considerable unconventional petroleum extraction projects, where bitumen is extracted from naturally-occurring oil sands ore. The large scale of these heavy crude oil developments raises concerns because of their potential to distribute and/or otherwise influence the occurrence, behaviour, and fate of environmental contaminants. Naphthenic acids (NAs) are one such contaminant class of concern in the AOSR, so studies have examined the occurrence and molecular profiles of NAs in the region. We catalogued the spatiotemporal occurrence and characteristics of NAs in boreal wetlands in the AOSR over a 7-year period, using derivatized liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comparing median concentrations of NAs across these wetlands revealed a pattern of NAs suggesting NAs in surface waters derived from oil sands deposits. Opportunistic wetlands that formed adjacent to reclaimed overburden and other reclamation activities had the highest concentrations of NAs and consistent patterns suggestive of bitumen-derived inputs. However, similar patterns in the occurrence of NAs were also observed in undeveloped natural wetlands located above the known surface-mineable oil sands deposit that underlies the region. Intra-annual sampling results along with inter-annual comparisons across wetlands demonstrated that differences in the spatial and temporal NA concentrations were dependent on local factors, particularly when naturally occurring oil sands ores were observed in the wetland or drainage catchment.

Evaluation of impacts of climate change on natural and managed wetland basins

AbstractLow floodplain wetlands such as the Western Everglades in South Florida are vulnerable to extreme weather events, and their water quality and ecosystem functions vary greatly depending on changes in water levels and discharges. The future (i.e., the mid and late 21st century) climate is projected to result in increased frequency and magnitude of extreme events, which could negatively affect the hydroecological function of the wetlands. Wetland management practices have commonly been implemented to protect wetlands and their functions, but it is not clear whether the current management practices can still be effective in projected climate change scenarios. The main goal of this study was to evaluate the impacts of climate change on the runoff and total phosphorus (TP) of natural (L28 Gap) and managed (L28) wetland watersheds in the Western Everglades. For the assessment, we employed future climate projections made using 29 general circulation models (GCMs) and the Watershed Assessment Model (WAM), a watershed loading model. The WAM was calibrated and validated for the baseline period (2000–2014), and the bias‐corrected climate projections were incorporated into the model to project the runoff discharge and TP loads for the near‐future (2030–2044) and far‐future (2070–2084) periods in two carbon emission scenarios. The modeling results show that the natural wetland watershed would be more vulnerable to projected climate change than the managed wetland watershed. The impact of projected climate change scenarios on daily runoff and TP loads was modulated by water control facilities and practices in the managed watershed, highlighting the significance of watershed management practices for improved water quality under projected climate change. This study demonstrates how the local natural and managed wetland watersheds distinctly respond to the global‐scale changes and emphasizes the role of water management practices in wetland basins, which are expected to help develop effective climate change adaptation plans for improved sustainability of wetland systems.

Spatio-temporal variation of groundwater pollution in urban wetlands and management strategies for zoning

Groundwater is an important resource to maintain the sustainable development of urban wetlands. The Jixi National Wetland Park (JNWP) was studied to realize the refined prevention and control of groundwater. The self-organizing map-K-means algorithm (SOM-KM), improved water quality index (IWQI), health risk assessment model and forward model were used comprehensively to evaluate the groundwater status and solute sources in different periods. The results showed that the groundwater chemical type in most areas was the HCO3–Ca type. Groundwater chemistry data from different periods were clustered into five groups. Groups 1 and 5 are affected by agricultural and industrial activities, respectively. The IWQI value in the normal period was higher in most areas due to the influence of spring ploughing. The east side of the JNWP was disturbed by human activities, and the quality of drinking water continued to deteriorate from the wet period to the dry period. 64.29% of the monitoring points showed good irrigation suitability. The health risk assessment model showed that the health risk was the largest in the dry period and the smallest in the wet period. The main factors causing health risks in the wet period and other periods were NO3− and F−, respectively. The overall cancer risk was within acceptable limits. The forward model and ion ratio analysis showed that the weathering of carbonate rocks was the main factor affecting the evolution of groundwater chemistry, accounting for 67.16%. The high-risk areas of pollution were mainly concentrated in the east of the JNWP. K+ and Cl− were the key monitoring ions in the risk-free zone and potential risk zone, respectively. The research can be used to help decision-makers carry out fine zoning control of groundwater.

Denitrification Potential of Surface Soils of Constructed Wetlands in Newtown Creek, an Urban Superfund Site.

Denitrification, the anaerobic microbial conversion of nitrate (NO3 - ), a common water pollutant, to nitrogen (N) gases, is often high in the soil of natural wetlands. In areas where natural wetlands have been degraded or destroyed, constructed and restored wetlands have been used to restore ecosystem services like denitrification. Thus, denitrification in restored and constructed wetlands could play an important role in treating anthropogenic N sources such as combined sewer overflow (CSO) discharges which can be high in NO3 - . In this study, we measured denitrification potential using an anaerobic slurry assay and made a suite of ancillary measurements (soil moisture content, microbial biomass carbon (C) and N content, potential net N mineralization and nitrification, soil inorganic N pools and soil respiration) in four constructed salt marsh wetlands, and a series of wetland habitat basins in Newtown Creek, NY, an urban superfund site. Samples were also taken from natural salt marshes located at Paerdegat Basin, Jamaica Bay, NY. Our results show that constructed Spartina alterniflora marshes in ultra-urban Newtown Creek support denitrification potential equivalent to rates of natural marshes in Jamaica Bay and reference marshes in other urban estuaries. There were significant positive correlations between microbial biomass C and N content and organic matter content and denitrification potential. Results suggest that constructed wetlandscan support wetland vegetation, soils, and microbial life and contribute to N removal under ultra-urban conditions. This article is protected by copyright. All rights reserved.