Wetland Area Research Articles

Landscape ecological risk evaluation and prediction under a wetland conservation scenario in the Sanjiang Plain based on land use/cover change

Landscape ecological risk is the term used to describe potential negative effects of the relationship between environmental processes and landscape structure as a result of both natural and human interactions. The scientific assessment of past and prediction future ecological risks to landscapes is the basis for achieving sustainable regional development. In this study, we built an ecological risk measurement system characterized by variability in landscape composition to reflect the components of landscape ecological risk. In particular, the CA-Markov model was used to simulate the spatial pattern of land use in the Sanjiang Plain, China, under a wetland protection scenario. The evolution of the spatiotemporal land use trend in the study area was then analyzed for past (2011–2021) and future (2021–2036) periods. The results identified that construction land, farmland, water, and grassland areas exhibited an increasing trend from 2011 to 2021, while forest and wetland areas decreased each year. From 2021 to 2036, the grassland areas exhibited a downward trend, while the other land use types maintained the same previous trend, and all land use types experienced a slowdown in the degree of change. The major landscape ecological risk levels in the research region changed from medium-risk and low-risk levels (2011–2021) to low-risk and lower-risk levels (2021–2036). An evident decrease in risk is observed for farmland and construction land in the mid-region of the research district and forests in the south. In contrast, high-risk and higher-risk levels regions were smaller and distributed in the Songhua River basin in the northeast of the research region, wetland nature reserves, and the Xingkai Lake area, with an overall reduction of 59%. Based on the results, we propose several risk prevention and control management strategies. This research acts as a basis for determining Sanjiang Plain's future rational distribution of land resources and provides an example for the reduction of ecological risks in similar regions.

Research on the connectivity of urban river network-wetland and water quality simulation.

The connectivity of urban river networks plays an important role in cities in many aspects, such as urban water safety, water quality (WQ), and aquatic ecological balance. This study focuses on the river network and the Majiawan Wetland in the Chaoyang District of Beijing by establishing a two-dimensional hydrological WQ model employing various water allocation schemes between the river network and the wetland. Water circulation and WQ are the main indexes, and the effects of different scenarios on improving water circulation and WQ are simulated and compared. This study demonstrates that the addition of water replenishment at the intersection of river network and internal slow-water zones of the wetland (Scheme 2) has greater effectiveness in improving both hydrology and WQ compared to two other schemes. The water area of the Majiawan Wetland has expanded, and water velocity has increased. Using chemical oxygen demand, total nitrogen, and total phosphorus as the index values for determining the water class, the WQ of about 20% of the wetland area was reached Water Class II (domestic drinking water), with Water Class III (general industrial water) accounting for the other 80%. This study provides valuable evaluation and reference for similar areas of urban river network connectivity.

Deteriorating habitat suitability and connectivity of waterbirds in the Bohai Sea Rim: Consequences of land use transformation

Wetlands in the Bohai Sea Rim play an indispensable role in maintaining the stability of waterbird populations on the East Asian-Australian flyway. However, motivated by economic development and urban expansion, coastal wetlands in this region have been extensively reclaimed, leading to a decline in the area and degradation of natural wetlands over the past two decades. We analyzed the temporal and spatial changes of suitable habitats of different groups of waterbirds and quantified habitat connectivity changes and the importance of different patches by using the Probability of Connectivity. The results show that the suitable habitat area of all the different groups of waterbirds decreased sharply from 2000 to 2020. In addition, the utilization ratio by waterbirds of artificial habitats increased. Land use is the primary environmental variable determining the distribution of suitable habitats. Meanwhile, the connectivity of habitats of different groups of waterbirds has also been declining. However, the patches of Tianjin and Hebei in Bohai Bay still have high importance for waterbirds, particularly shorebirds. Expanding existing protection areas to cover the above-mentioned patches is recommended. We also advocate stricter protection measures and necessary ecological restoration activities on both the natural and artificial wetlands.

Prevalence of and factors associated with zero-dose and under-immunized children in selected areas of Bangladesh: Findings from Lot Quality Assurance Sampling Survey

BackgroundIn the era of Gavi’s 5.0 vision of “leaving no one behind with immunization”, childhood routine vaccination in missed communities is considered as a priority concern. Despite having a success story at the national level, low uptake of immunization is still persistent in selected pocket areas of Bangladesh. However, prevalence and the associated factors of zero-dose (ZD) and under-immunization (UI) are still unknown at those geo-pockets of Bangladesh. Thus, the study aims to report and identify the factors associated with ZD and UI in selected geographical locations. MethodsThis study used data from a Lot Quality Assurance Sampling (LQAS) survey where 504 households from 18 clusters of four hard to reach (HTR) and one urban slum were included. Caregivers of children aged 4.5 to 23 months were interviewed. Three outcome variables- ZD, UI and ZD/UI were considered and several related attributes were considered as independent variables. Data were analyzed through bivariate analysis, binary logistic regression and dominance analysis. ResultsOverall, 32% of the children were either ZD (8%) or UI (26%) in the selected areas. The adjusted odds of ZD/UI for urban slum and haor (wetlands) areas were 5.62 and 3.61 respectively considering coastal areas as reference. However, distance of nearest EPI center, availability of EPI card, age of caregivers, education and occupation of mother and number of earning members in household were influential factors for ZD/UI. According to dominance analysis, availability of EPI card can explain the most of the variation of ZD/UI in this study. ConclusionThe study findings highlight the high prevalence ZD/UI in certain geo-pockets of the country. It provided a powerful insight of current situation and associated factors in regards to ZD/UI in the country which will help policy-makers and programme managers in designing programmes to reduce missed communities in Bangladesh.

Dynamic monitoring and restorability evaluation of alpine wetland in the eastern edge of Qinghai–Tibet Plateau

Accurate monitoring of alpine wetland areas and scientific evaluation of alpine wetland restorability play important roles in revealing the changing mechanism of the ecological environment. However, because of the complexity and lack of spatial data, few studies on evaluation index system of restorability of alpine wetland considered wild animal habitat, such as habitat suitability index of black necked crane. Based on Landsat images of seven periods from 1990 to 2020, this study adopts the methods of spectral mixture analysis and change vector analysis to quantitatively demonstrate the variations and distribution patterns of alpine wetland ecosystem in the eastern edge of Qinghai–Tibet Plateau. The study focuses on determining the abundance of water, vegetation and soil, which the interannual variations represent as the shapes of ‘√’, mirror ‘N’ and normal ‘N’, respectively. In terms of natural ecological condition and human activity interference, we construct a comprehensive evaluation model of restorability of alpine wetland, separate the restorability district and construct the Bayesian network model to discuss the causal relationship between the restorability value and evaluation factor. Results show that the regions of alpine wetland in the study area changed most drastically from 1995 to 2000 and from 2000 to 2005. In addition, the total areas classified as suitable, relatively suitable and suitable for restoration account for 63.69 % of the study area, with a large potential for wetland restorability. Moreover, the prioritisation scheme of wetland restoration action includes the valley swamps of Heihe River in the middle, followed by the flat wetlands and grasslands in the south and lastly by uneven wetlands in the north.

Predicting the impact of climate change on the area of wetlands using remote sensing

Predicting the impact of climate change on the area of wetlands using remote sensing

Actual and reference evapotranspiration for a natural, temperate zone fen wetland – Upper Biebrza case study

Evapotranspiration is the key and predominant component of the water balance in wetlands. Direct evapotranspiration measurements are challenging in wetlands due to their remoteness and high surface water level. This article describes the actual (ETa and reference evapotranspiration (ET0) from a cultivated wet meadow located in the Biebrza National Park – the largest national park in north-east Poland, Central Europe. The data were sourced from a micrometeorological station equipped with an eddy covariance system to measure heat and vapour fluxes and such meteorological elements as radiation balance components, air temperature and humidity. The values of directly measured ETa were presented daily in the context of available energy and ET0. Daily sums of ETa ranged from below 0.2 mm in winter to 6.5 mm in summer. The share of daily sums of ETa in the ET0 usually ranged from 50 to 60%, with extreme values from 10 to 170%. Aside from giving more insight into Biebrza wetlands’ functioning, the actual data produced in this study may be used instead of indirect methods, which were used the most in modelling wetlands areas.

Ecological indicators and biological resources for hydrocarbon rhizoremediation in a protected area.

Spillage from oil refineries, pipelines, and service stations consistently leads to soil, food and groundwater contamination. Bacterial-assisted phytoremediation is a non-invasive and sustainable solution to eliminate or decrease the concentration of xenobiotic contaminants in the environment. In the present study, a protected area interested by a fuel discharge was considered to assess a bioremediation intervention. From the spill point, a plume of contamination flowed South-West into the aquifer, eventually reaching a wetland area. Soils, groundwaters and plants belonging to the species Scirpus sylvaticus (L.) were sampled. In the majority of the soil samples, concentrations of total petroleum hydrocarbons, both C ≤ 12 and C > 12, exceeded legal limits set forth in Directive 2000/60/EC. The analysis of diatom populations, used as ecological indicators, evidenced morphology alterations and the presence of Ulnaria ulna and Ulnaria biceps species, previously detected in hydrocarbon-polluted waters. Tests for phytotoxicity and phytodegradation, carried out in soil mesocosms, planted with Zea mays and Helianthus annuus, demonstrated that both species significantly contributed to the removal of total petroleum hydrocarbons. Removal of C ≤ 12 and C > 12 petroleum hydrocarbons was in the range of 80%-82% for Z. mays and 71%-72% for H. annuus. Microbial communities inhabiting high organic carbon and vegetated soils were more active in hydrocarbon degradation than those inhabiting subsoils, as evidenced by soil slurry experiments. The abundance of functional genes encoding toluene-benzene monooxygenase (tbmD) and alkane hydroxylase (alkB), quantified in environmental samples, confirmed that the plant rhizosphere recruited a microbial community with higher biodegradation capacity. Bacterial strains isolated from the sampling site were able to grow on model hydrocarbons (hexane, hexadecane and o-, m-, p-xylene) as sole carbon and energy sources, indicating that a natural bio-attenuation process was on-going at the site. The bacterial strains isolated from rhizosphere soil, rhizoplane and endosphere showed plant growth promoting traits according to in vitro and in vivo tests on Z. mays and Oryza sativa, allowing to forecast a possible application of bacterial assisted rhizoremediation to recover the protected area.

In Situ Utilization of Electron-Enhanced Degradation of Azo Dyes in a Constructed Wetland–Microbial Fuel Cell Coupling System

In this study, a constructed wetland was coupled with a microbial fuel cell to establish a coupled system known as the constructed wetland–microbial fuel cell (CW–MFC), utilized for the treatment of X-3B azo dye wastewater at varying concentrations. Experimental results indicated that the anodic region made the primary contributions to the discoloration of azo dyes and COD removal, with a contribution rate of 60.9–75.8% for COD removal and 57.8–83.0% for the effectiveness of discoloration. Additionally, the role of plants in the constructed wetland area could achieve the removal of small molecular substances and further discoloration. In comparison to open-circuit conditions, under closed-circuit conditions the CW–MFC effectively degraded X-3B azo dye wastewater. Under an external resistance of 2000 Ω, a maximum COD removal rate of 60.0% and a maximum discoloration rate of 85.8% were achieved for X-3B azo dye at a concentration of 100 mg/L. Improvements in the treatment efficiency of X-3B dye wastewater were achieved by altering the external resistance. Under an external resistance of 100 Ω and an influent concentration of X-3B of 800 mg/L, the COD removal rate reached 78.6%, and the decolorization rate reached 85.2%. At this point, the CW–MFC exhibited a maximum power density of 0.024 W/m3 and an internal resistance of 99.5 Ω. Spectral analysis and GC–MS results demonstrated the effective degradation of azo dyes within the system, indicating azo bond cleavage and the generation of numerous small molecular substances. Microbial analysis revealed the enrichment of electrogenic microorganisms under low external resistance conditions, where Geobacter and Trichococcus were dominant bacterial genera under an external resistance of 100 Ω, playing crucial roles in power generation and azo dye degradation within the system.

A Multi-Scenario Simulation and Dynamic Assessment of the Ecosystem Service Values in Key Ecological Functional Areas: A Case Study of the Sichuan Province, China

The ecosystem service value (ESV) is an important basis for measuring an ecological environment’s quality and the efficient management of ecosystems. It is particularly necessary to explore a proven methodology for assessing and predicting ESV dynamics coupled with policy-oriented scenarios that can provide a theoretical groundwork for macro decision, particularly in the context of implementing ecological protection and restoration projects. This study selected the land cover (LC) of Sichuan Province at five periods and the spatiotemporal dynamic equivalent factor method to assess the ESVs from 2000 to 2020. Additionally, the study coupled the Markov chain and GeoSOS-FLUS model, and predicted the future pattern of ESVs under four future development scenarios. The results show that (a) the areas of forests, shrubs, waters, wastelands, wetlands, and impervious areas showed a continuous increase from 2000 to 2020, with the most frequent interchanges occurring among croplands, forests, and grasslands. (b) The implementation of ecological protection and restoration projects led to a 13,083.32 × 108 yuan increase in ESV, and barycenter of the ESVs is located in the northeastern part of Ya’an and exhibits a tendency to move towards the northeast. (c) The ESV aggregation pattern of each city has remained unchanged, with Ganzi being the only city with a high aggregation. Overall, there are more conflict cities than coordination cities between economic development and the ecological environment. (d) The total ESV in 2025 will continue to increase under all development scenarios, reaching a maximum of 50,903.37 × 108 yuan under the EP scenario. This study can provide insights for ecological planning decisions and sustainable regional socio-economic development.

Centennial loss of lake wetlands in the Yangtze Plain, China: Impacts of land use changes accompanied by hydrological connectivity loss

Humans have played a fundamental role in altering lake wetland ecosystems, necessitating the use of diverse data types to accurately quantify long-term changes, identify potential drivers, and establish a baseline status. We complied high-resolution historical topographic maps and Landsat imagery to assess the dynamics of the lake wetlands in the Yangtze Plain over the past century, with special attention to land use and hydrological connectivity changes. Results showed an overall loss of 45.6 % (∼11,859.5 km2) of the lake wetlands over the past century. The number of lakes larger than 10 km2 decreased from 149 to 100 due to lake dispersion, vanishing, and shrinkage. The extent of lake wetland loss was 3.8 times larger during the 1930s–1970s than that in the 1970s–1990s. Thereafter, the lake wetland area remained relatively stable, and a net increase was observed during the 2010s–2020s in the Yangtze Plain. The significant loss of lake wetland was predominately driven by agricultural activities and urban land expansion, accounting for 81.1 % and 4.9 % of the total losses, respectively. In addition, the changes in longitudinal and lateral hydrological connectivity further exacerbated the lake wetland changes across the Yangtze Plain through isolation between lakes and the Yangtze River and within the lakes. A total of 130 lakes have been isolated from the Yangtze River due to the construction of sluices and dykes throughout the Yangtze Plain, resulting in the decrease in the proportion of floodplain marsh from 28.3 % in the 1930s to 8.0 % in the 2020s. Furthermore, over 260 sub-lakes larger than 1 km2 (with a total area of 1276.4 km2) are experiencing a loss of connectivity with their parent lakes currently. This study could provide an improved historical baseline of lake wetland changes to guide the conservation planning to wetland protection and prioritization area in the Yangtze Plain.

Spatial interactions between perceived biophilic values and neighborhood typologies in urban wetlands

Wetlands provide a wide range of ecosystem services; however, little is known about their perception value or use for improving urban planning and wetland management. This study explores the perception values towards the Los Batros Wetland in Chile, by inhabitants from different neighborhood typologies. A sample of 457 responses evaluated the wetland by applying the Kellert framework of 9 biophilic values using a Public Participation Geographic Information Systems (PPGIS) approach. A spatial autocorrelation analysis with hotspot revealed that the spatial distribution of biophilic values varies by neighborhood typology. Subsequent ANOVA and T-test suggest that such distribution is affected by perceived accessibility and visitation purposes, and is influenced by socio-demographic aspects that vary among neighborhood typology. Inhabitants of the garden city typology located next to the wetland area, whose residents have higher education and income levels and who have easy and moderate access to the wetland, agreed with a diverse type of biophilic values. In the garden city, the ecologistic-scientific value has the higher spatial concentration. In the condominium typology, with similar education and income levels and accessibility, but situated far from the wetland, there was less agreement with biophilic values, and these were more dispersed, i.e. biophilic values are less representative. In this case, the aesthetic value prevails over others. At the north area of the neighborhood unit, where residents had lower education and income levels along with moderate to difficult physical access to the wetland, but they developed horticultural activities alongside the wetland, inhabitants agree with various biophilic values, highlighting its symbolic value. Conversely, biophilic values of people in the favela were not in agreement nor disagreement, regardless they have similar physical access and distance to the wetland as residents in the condominium typology, but have the lowest income and education level. Findings suggest that effective wetlands management requires appreciation of the clusters of values assigned to wetland environments, which in this case relate to neighborhood typologies. These clusters should be considered when planning to restore, protect, and improve urban wetlands.

Climate drivers and human impacts shape 35‐year trends of coastal wetland health and composition in an urban region

AbstractThe future of coastal wetlands will depend on the combined effects of climate change and human impacts from urbanization and coastal management. Disentangling the effects of these factors is difficult, but satellite imagery archives provide a way to track biological and physical changes in wetlands over recent decades to reveal how coastal wetlands have been changing in response to climate and human drivers. In this study, we used Landsat to monitor the conditions of 32 coastal wetlands in southern California from 1984 to 2019 and identify environmental and human drivers of these trends. Wetland conditions were characterized by vegetation greenness, using the normalized difference vegetation index (NDVI), and by habitat composition, derived from areal estimates of wetland and subtidal habitats. Overall, wetlands displayed three types of long‐term response: greening and gaining wetland (10), greening and losing wetland (16), and browning and losing wetland (6). Regional environmental drivers with overall positive effects on wetland NDVI were sea level, wave height, and precipitation, whereas stream discharge, vapor pressure deficit, and air temperature had negative or nonlinear effects. Wetland area change was primarily correlated with sea level, but response was highly contextual among sites. Negative trends in wetland NDVI and area were more common in larger sites with low elevations and in sites with open inlets. Restoration had mixed effects, with only half of the restored sites showing positive changes in NDVI and wetland area post‐restoration. The important work of managing and restoring urban coastal wetlands is complicated by variability and context and requires us to account for the influence of humans and climate as we build a regional understanding of historic, present, and future wetland health.

Three faces of climate change: Using Q-methodology to understand farmers’ perspectives of climate change and adaptive capacity in Bangladesh’s wetland areas

Even though the weather-dependent agricultural sector is severely impacted by climate change and requires more adaptive measures, climate change adaptation in the global south is slow. The perception of farmers, who are the final decision-makers, strongly influences the adoption of climate-smart technologies and the (un)willingness to follow recommended measures. Although perception studies have attracted the international community’s interest, these studies have disregarded the heterogeneity within the farming community. Our study uses Q-methodology to address this gap by examining small-scale farmers’ perspectives on climate change and their perceived adaptation capacity in wetland areas of north-eastern Bangladesh. Following post-sort interviews, 36 farmers were invited to participate in the Q-sorting using 34 pre-selected statements. The study revealed three distinct types of perspectives on climate change and adaptive capacity: theists who believe in the act of God and take a “do nothing” approach, realists who believe in climate change but are unaware of climate change trade-offs, and pragmatists who recognize climate change and actively pursue adaptations. The awareness of different climate change perspectives can support policymakers and extension service providers. By replacing their one-size-fits-all approach, they can better assist wetland farmers in developing and implementing tailored adaptation strategies.

Changes in wetland landscape and inundation patterns in the middle and lower reaches of the Yangtze River Basin from 1990 to 2020

Wetlands are crucial to diverse societies and ecosystems but are threatened globally. Natural wetlands in the middle and lower reaches of the Yangtze River Basin (MLRYRB) have long been exploited to meet the increasing food and energy demands, especially in recent decades. However, how their landscapes and hydrological patterns changed over time was poorly qualified, which was crucial to conserving biodiversity and ecosystems. In this study, we proposed a new wetland classification procedure taking advantage of the shape, topography, landscape patterns, and phenology to map the distribution of six wetland types in the MLRYRB in 1990 and 2020 with Landsat images. The transitions among different wetland types and associated driving factors were examined. Artificial wetlands expanded by 3907.6 km2 while natural wetlands decreased by 423.2 km2, resulting in a net area increase of 3484.4 km2. Farmland reclamations, aquacultural activities, urban expansion, and dam constructions induced 70 % of the area's loss of natural wetlands. Meanwhile, spatiotemporal patterns in wetland inundation dynamics were determined with agglomerative hierarchical cluster analysis. Widespread transitions from perennial water to seasonal wetlands were detected. Notably, 47.8 % of the natural wetlands experienced significant drying trends, and as a result, the mean yearly inundated periods for natural wetlands decreased from 303 days in 1990 to 272 days in 2020. Given the substantial structural alterations, wetland destruction was more severe than the area reflected. Our results suggested that category-based changes in wetland areas, inundation patterns, associated driving forces, and underlying ecological consequences should be comprehensively assessed to conduct scientific conservation and prevent “paper offsets.”

Analysing sensitivity of conditioning factors for wetland habitat quality modelling

Wetland habitat quality degradation, in addition to wetland loss, is a growing concern that demands rapid action. The purpose of the current study is to assess the sensitivity analysis of conditioning factors on the Wetland Habitat Quality State (WHQS) in the Rarh tract of Murshidabad, West Bengal. Total seventeen metrics in total, including water quality, hydrology, and landscape composition were employed to mapping WHQS. WHQS was modelled using machine learning techniques. The efficiency of the models was evaluated using statistical methods such as the Receiver operating characteristics (ROC) curve. Very strong portions of wetland area have been decreased from 32.74% in 1990 to 20.72% in 2020. According to the study, wetland fragmentation, distance from agricultural land, and trophic status factor of the wetlands are key elements that affect wetland habitat quality to a large extent. The current study's findings could serve as the foundation for developing water resource management plans for the management, conservation, and restoration of wetlands, in addition to doing extensive research on monitoring habitat quality in wetlands.

Carbon fluxes of China's coastal wetlands and impacts of reclamation and restoration.

Coastal wetlands play an important role in regulating atmospheric carbon dioxide (CO2) concentrations and contribute significantly to climate change mitigation. However, climate change, reclamation, and restoration have been causing substantial changes in coastal wetland areas and carbon exchange in China during recent decades. Here we compiled a carbon flux database consisting of 15 coastal wetland sites to assess the magnitude, patterns, and drivers of carbon fluxes and to compare fluxes among contrasting natural, disturbed, and restored wetlands. The natural coastal wetlands have the average net ecosystem exchange of CO2 (NEE) of -577 g C m-2 year-1, with -821 g C m-2 year-1 for mangrove forests and -430 g C m-2 year-1 for salt marshes. There are pronounced latitudinal patterns for carbon dioxide exchange of natural coastal wetlands: NEE increased whereas gross primary production (GPP) and respiration of ecosystem decreased with increasing latitude. Distinct environmental factors drive annual variations of GPP between mangroves and salt marshes; temperature was the dominant controlling factor in salt marshes, while temperature, precipitation, and solar radiation were co-dominant in mangroves. Meanwhile, both anthropogenic reclamation and restoration had substantial effects on coastal wetland carbon fluxes, and the effect of the anthropogenic perturbation in mangroves was more extensive than that in salt marshes. Furthermore, from 1980 to 2020, anthropogenic reclamation of China's coastal wetlands caused a carbon loss of ~3720 Gg C, while the mangrove restoration project during the period of 2021-2025 may switch restored coastal wetlands from a carbon source to carbon sink with a net carbon gain of 73 Gg C. The comparison of carbon fluxes among these coastal wetlands can improve our understanding of how anthropogenic perturbation can affect the potentials of coastal blue carbon in China, which has implications for informing conservation and restoration strategies and efforts of coastal wetlands.

Ecological restoration trajectory of the Taitema Lake wetland in arid northwest China: A 36-year wetland health assessment using Landsat time series data

The Taitema Lake wetland in the lower reaches of the Tarim River (northwest China) is sensitive to hydrological changes and provides necessary ecosystem functions for biodiversity conservation. Monitoring and evaluating the long-term dynamics of the Taitema Lake wetland is essential for conserving and restoring regional wetland ecosystems. This paper used a dense time series of Landsat images from 1986 to 2021 to map the Taitema Lake wetlands. It analyzed the annual and seasonal variations of the wetlands by ten ecological indicators, which include area extent, vegetation, hydrology, and landscape features. A systematic assessment of the ecological quality of the wetlands over the past 36 years, along with their influencing factors, was conducted from the perspective of wetland health. The results showed that (1) the recovered water areas and the wetlands showed a clear trend of ecological restoration since 2000, accompanied by an increased fragmentation. The total wetland area increased from 69.95 km2 in 1986 to 1164.47 km2 in 2021, with a 15.6-fold increase, and the vegetation area increased twentyfold to 639.84 km2. (2) The wetness in the core zone increased consistently across seasons, coupled with a simultaneous vegetation expansion surrounding the core zone. The areas with increasing wetness levels account for 48 % during winter and spring, and the areas with vegetation expansion account for 81 % and 72 % in summer and autumn, respectively. (3) The wetland ecological health status recovered to a “Good” level in 2021 and has not reached the “Excellent” status. The expansion of the water body is the primary driver behind the promotion of wetland ecological recovery. Small water bodies within the area range of 0.05 to 0.1 km2 notably exhibited the most stimulating effects on the wetlands. Thus, increasing the count of smaller water bodies helps rehabilitate vegetation growth and mitigating the water supply’s stress to sustain large lacustrine bodies.

Spatial Variations in Microplastics in the Largest Shallow Lake of Central Europe and Its Protecting Wetland Area

The concentration of microplastics (MPs) in two important Hungarian freshwater habitats was determined in the size range of 50 μm–1 mm. Lake Balaton (LB) is the largest shallow lake in Central Europe, with a significant role in recreation and tourism. Its main inflow, the Zala River, enters the lake through an artificially constructed wetland, the Kis-Balaton Water Protection System and its catchment area (KB), which helps preserve the water quality of the lake. From these two areas, 15 samples were taken with an in situ filtration sampling method. After preparation, the samples were analyzed automatically by FT-IR microscopy. All samples, from both areas, contained MPs; the dominant microplastic (MP) shape was the fragment, while the most frequently polymer types were polyethylene, polypropylene and alkyd. Small MPs were dominant in both areas; around 90% of the MPs were smaller than 500 μm. On average, LB contained more MPs (21.0 ± 12.5 MPs/m3) compared to the KB, which presented an average concentration of MPs of 7.8 ± 5.9 MPs/m3. In the examined areas, two potential MP sources were determined, i.e., treated wastewater and road traffic. The importance of tourism should also be further investigated.

Uranium Biogeochemistry in the Rhizosphere of a Contaminated Wetland.

The objective of this study was to determine if U sediment concentrations in a U-contaminated wetland located within the Savannah River Site, South Carolina, were greater in the rhizosphere than in the nonrhizosphere. U concentrations were as much as 1100% greater in the rhizosphere than in the nonrhizosphere fractions; however and importantly, not all paired samples followed this trend. Iron (but not C, N, or S) concentrations were significantly enriched in the rhizosphere. XAS analyses showed that in both sediment fractions, U existed as UO22+ coordinated with iron(III)-oxides and organic matter. A key difference between the two sediment fractions was that a larger proportion of U was adsorbed to Fe(III)-oxides, not organic matter, in the rhizosphere, where significantly greater total Fe concentrations and greater proportions of ferrihydrite and goethite existed. Based on 16S rRNA analyses, most bacterial sequences in both paired samples were heterotrophs, and population differences were consistent with the generally more oxidizing conditions in the rhizosphere. Finally, U was very strongly bound to the whole (unfractionated) sediments, with an average desorption Kd value (Usediment/Uaqueous) of 3972 ± 1370 (mg-U/kg)/(mg-U/L). Together, these results indicate that the rhizosphere can greatly enrich U especially in wetland areas, where roots promote the formation of reactive Fe(III)-oxides.