Wetland ecosystem services research: A critical review

Losses and destabilization of soil organic carbon stocks in coastal wetlands converted into aquaculture ponds

Coastal-wetlands play a crucial role as carbon (C) reservoirs on Earth due to their C pool composition and functional sink, making them significant for mitigating global climate change. However, due to the development and utilization of wetland resources, many wetlands have been transformed into other land-use types. The current study focuses on the alterations in soil organic-C (SOC) in coastal-wetlands following reclamation into aquaculture ponds. We conducted sampling at 11 different coastal-wetlands along the tropical to temperate regions of the China coast. Each site included two community types, one with solely native species (Suaeda salsa, Phragmites australis and Mangroves) and the other with an adjacent reclaimed aquaculture pond. Across these 11 locations we compared SOC stock, active OC fractions, and soil physicochemical properties between coastal wetlands and aquaculture ponds. We observed that different soil uses, sampling sites, and their interaction had significant effects on SOC and its stock (p < .05). Reclamation significantly declined SOC concentration at depths of 0-15 cm and 15-30 cm by 35.5% and 30.3%, respectively, and also decreased SOC stock at 0-15 cm and 15-30 cm depths by 29.1% and 37.9%, respectively. Similar trends were evident for SOC stock, labile organic-C, dissolved organic-C and microbial biomass organic-C concentrations (p < .05), indicating soil C-destabilization and losses from soil following conversion. Soils in aquaculture ponds exhibited higher bulk density (BD; 11.3%) and lower levels of salinity (61.0%), soil water content (SWC; 11.7%), total nitrogen (TN) concentration (23.8%) and available-nitrogen concentration (37.7%; p < .05) than coastal-wetlands. Redundancy-analysis revealed that pH, BD and TN concentration were the key variables most linked with temporal variations in SOC fractions and stock between two land use types. This study provides a theoretical basis for the rational utilization and management of wetland resources, the achievement of an environment-friendly society, and the preservation of multiple service functions within wetland ecosystems.

Modeling the spatial relationship between landscape services and vulnerability assessment

Even though many studies have been thus far devoted to landscape services (LS) or vulnerability assessment (VA) alone, the relationship between these two concepts has been less investigated. The current study attempts to model the spatial relationship between LS and VA in the Tarhan area (west of Iran). For this purpose, a combination of the analytic hierarchy process (AHP), remote sensing (RS), and geographic information system (GIS) techniques are applied to assess vulnerability. Variogram models and geostatistical simulations are used for mapping and evaluating landscape services. Moreover, the geographically weighted regression (GWR) is operated to predict the relationship between LS and VA. The results indicate that landform and socioeconomic variables are also two main factors shaping variations in VA. As well, the levels of services provided in the possible landscape are affected by the vulnerability. The assessment accordingly establishes that natural and cultural values have significant effects on services, in terms of their spatial distribution and nature. Exploring the relationship between LS and VA correspondingly depicts that VA has a direct influence on the capacity and entity of LS provision (adjusted R2 = 0.67). The outcomes of the study provide a foundation for nature management and conservation, although it is less able to analyze the trade-off between ecosystem degradation and future development trends. The nexus of LS and future ecological processes in an integrated system can be thus the subject of further research.

Soil salinization in agriculture: Mitigation and adaptation strategies combining nature-based solutions and bioengineering

Soil salinization is among the most critical threats to agriculture and food security. Excess of salts adversely affects soil structure and fertility, plant growth, crop yield, and microorganisms. It is caused by natural processes, such as dry climates and low precipitations, high evaporation rate, poor waterlogging, and human factors, such as inappropriate irrigation practices, poor drainage systems, and excessive use of fertilizers. The growing extremization of climate with prolonged drought conditions is worsening the phenomenon. Nature-based solutions (NBS), combined with precision or conservation agriculture, represent a sustainable response, and offer benefits through revitalizing ecosystem services. This perspective explores NBS that can be adopted, along with their challenges and implementation limitations. We also argue that NBS could not be enough to combat hunger in the world's most vulnerable regions and fully achieve the Sustainable Development Goal - Zero Hunger (SDG2). We therefore discuss their possible combination with salt-tolerant crops based on bioengineering.

Wetland Destruction in a Headwater River Leads to Disturbing Decline of In-stream Nitrogen Removal

Wetlands have long been recognized as efficient nitrogen (N) processing systems. While widespread interest is in constructing wetlands to mitigate N pollution, there is a dearth of information about the environmental consequences following wetland dismantlement. This study elucidated the changing trajectories of water quality and N removal capacity in a headwater river that initially contained a series of constructed wetlands but later underwent wetland destruction. An estimated 17% surge in total N concentration has been reported since the wetlands' destruction. This adverse trend is primarily attributed to a weakened in-stream N removal capacity, which was reduced to a mere 25% of the levels observed when the wetlands were operational. Further analysis confirms that the presence of wetlands actively shapes desirable environmental settings for N processing. In stark contrast, wetland destruction leads to unfavorable environmental conditions, which not only restrain in-stream anaerobic metabolisms but also trigger algal proliferation and biological N fixation. Collectively, this research provides compelling evidence of the detrimental consequences associated with wetland destruction, emphasizing the need for remedial strategies to mitigate these negative effects.

More Than a Service: Values of Rivers, Wetlands and Floodplains Are Informed by Both Function and Feeling

How people value rivers, wetlands and floodplains influences their attitudes, beliefs and behaviours towards these ecosystems, and can shape policy and management interventions. Better understanding why people value rivers, wetlands and floodplains and their key ecosystem components, such as vegetation, helps to determine what factors underpin the social legitimacy required for effective management of these systems. This study sought to ascertain perspectives on the value of non-woody vegetation in river-floodplain systems via an online survey. The survey found that participants valued non-woody vegetation for their provision of a range of ecosystem functions and services, with strong emphasis on ecological aspects such as regulation functions, habitat provision and biodiversity. However, the inclusion of a question framed to focus on stories or narratives resulted in a different emphasis. Responses indicated that non-woody vegetation, and rivers, wetlands and floodplains were valued for the way they made people feel through lived experiences such as recreational activities, personal interactions with nature, educational and research experiences. This highlights the important role of storytelling in navigating complex natural resource management challenges and ascertaining a deeper understanding of values that moves beyond provision of function to feeling. Improved understanding of the diverse ways people value and interact with river-floodplain systems will help develop narratives and forms of engagement that foster shared understanding, empathy and collaboration. Appreciation of plural values such as the provision of functions and services along with the role of emotional connections and lived experience will likely increase lasting engagement of the general public with management to protect and restore river-floodplain systems.

Economic and socioecological perspectives of urban wetland loss and processes: a study from literatures

Existing literatures across the world highlighted the causes and rate of wetland loss; however, so far, no researches tried to analyze how these are guided by the socioeconomic and ecological conditions. The current review work wished to explore how economic and socioecological perspectives could control the rate and drivers of urban wetland loss. Through meta-analysis, this study also intended to explore the changing polarity in research publication and collaborative research. Total 287 original research articles indicating the rates and drivers of wetland loss from 1990 to June 2022 for the first objective and 1500 articles focusing wetland researches from Dimensions AI database for the last objective were taken.Results clearly revealed that the rate of urban wetland loss varies from 0.03 to 3.13% annually, and three main drivers like built-up, agricultural expansions, pollution were identified all across the world. Loss rate was found maximum in the developing and least developed countries. Pollution, built-up expansion, and agriculture expansion, respectively, in developed, developing, and least developed nations were identified as the most dominant drivers of urban wetland loss. Linking loss rate and drivers with socioecological and economic perspectives revealed that human development index (HDI), ecological performance index (EPI), sustainable development goal index (SDGI), and social progress index (SPI) is negatively associated with the rate of urban wetland loss. Contrarily, a poverty rate encouraged higher rate of loss. This study articulated that improving these socioecological and economic conditions could help wetland conservation and restoration to achieve SDGs.

Military activity and wetland-dependent wildlife: A warfare ecology perspective

Wetlands provide unique habitat functions that benefit society by provisioning food, recreation, and ecosystem sustainability. Warfare affects the habitats of wetland-dependent reptiles, amphibians, and birds in both positive and negative ways, and opportunities exist to improve the management of wildlife habitat using a warfare ecology framework. Recent events in Ukraine highlight these relationships and provide stimulus to further consider the implications of current events for natural resources. In response, this commentary highlights both degradational and positive impacts of warfare on wetland fauna during the cyclical preparation, active conflict, and recovery phases. For example, the active conflict phase often initiates ecological disturbance regimes that couple large-scale landscape alteration with the release of chemicals and other materials into wetlands, leading to reduced reproductive potential and population declines in wetland-dependent species (e.g., amphibians, waterfowl) along with decreased overall wetland biodiversity and habitat quality. In contrast, wetland-dependent wildlife can benefit from (1) conservation activities occurring on military installations maintained to support training activities and (2) restoration efforts initiated after the cessation of combat. For example, many threatened and endangered reptiles and amphibians find refugia on military lands in the USA and internationally, and international protections for wetland resources (including the Ramsar Convention) have been established to promote their sustainability and wise use. Additional research is needed to improve the protection of valuable wetland resources by further enhancing ongoing conservation and planning efforts and improving strategies to mitigate the negative impacts of warfare on wetland dependent species throughout each phase of the warfare ecology cycle. Integr Environ Assess Manag 2023;00:1-9. Published 2023. This article is a US Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Constructed Wetlands Suitability for Sugarcane Profitability, Freshwater Biodiversity and Ecosystem Services

Freshwater ecosystems, such as wetlands, are among the most impacted by agricultural expansion and intensification through extensive drainage and pollution. There is a pressing need to identify ways of managing agricultural landscapes to ensure food and water security without jeopardising biodiversity and other environmental benefits. Here we examine the potential fish biodiversity and landholder financial benefits arising from the integration of constructed lagoons to improve drainage, flow regulation and habitat connectivity within a sugarcane dominated catchment in north Queensland, Australia. A hybrid approach was used, combining the findings of both fish ecological surveys and a financial cost-benefit analysis. We found that the constructed lagoons supported at least 36 native freshwater fishes (over half of all native freshwater fishes in the region), owing to their depth, vegetated margins, moderate water quality and high connectivity to the Tully River. In addition to biodiversity benefits, we estimated that surrounding sugarcane farms would have financially benefited from reduced flooding of cropland and the elevation of low-lying cropland with deposited spoil excavated from lagoon construction. Improved drainage and flow regulation allowed for improvement in sugarcane yield and elevated land increased gross margins from extending the length of the cane production cycle or enabling a switch from cattle grazing to cane production. Restoring or creating wetlands to reduce flooding in flood-prone catchments is a globally applicable model that could improve both agricultural productivity and aquatic biodiversity, while potentially increasing farm income by attracting payments for provision of ecosystem services.

How far the types and wetland hydrological conditions influence its provisioning services in the Indian mature Ganges delta

Present work intended to explore how far the Provisioning Service Value (PSV) of the mature Ganges deltaic wetlands is determined by its typology and a few physical attributes like hydrology and aquatic vegetations. Firstly, a field investigation was carried out in the representative sample sites, and field-measured PSV was calibrated with wetland types, hydrological security, and aquatic plant biomass to perform spatial estimation and mapping of PSV. The estimation yielded average annual PSV of entire wetlands as 146.5 × 10⁵ Indian Rupee (INR)/km²/year, with the highest over bheries (embankments for fish and shrimp aquaculture) 176 × 10⁵ INR/km²/year and lowest over marshy wetlands 107 × 10⁵ INR/km²/year. Sensitivity analysis of this estimation showed in cases of 55% field visited sites, the field-measured PSV was outside the range of low standard regression residuals (-0.5 to 0.5). While searching for the reason behind such error in the estimation, the variability of the field-measured PSV was measured. Various inequality measures showed high inequality in inter and intra-hydrological conditions of the wetland. Analysis of variance (ANOVA) proved statistical significance of within-class variability. To explain the variability of PSV, Kernel Density Estimation (KDE) plotting was performed, incorporating a few other regional conditioning factors like wetland size, fish and shrimp aquaculture, perenniality, expenditure, and external feeding from the experience of the field. From this excesize, external feeding and expenditure were essential factors that should be incorporated along with the wetland characteristics and physical attributes for accurate estimation. Since producing spatial data layers of these factors with a finer resolution is difficult, the study suggests case-specific estimation of PSV instead of general spatial mapping.

The Transformation of 40-Year Coastal Wetland Policies in China: Network Analysis and Text Analysis

The notable improvement of China's wetland management policies over the last four decades prompted this study's goal to quantitatively analyze the transformation of China's coastal wetland policies from 1979 to 2022 by applying an institutional network analysis and policy text analysis. The results of the institutional network analysis revealed an administrative management transformation from a multidepartmental mode to an integrated management framework. Furthermore, the policy text analysis results revealed a change in policy priorities (from exploitation to protection) and management targets (from a single environmental element to a comprehensive ecosystem and further to collaborative governance). In addition, the overall outcome of this study instigated proposals for the improvement of future wetland policies on climate change, integrated planning, natural capital, and public participation. Hence, this study presents an example of wetland policy analysis based on a quantitative review, which we hope will also be valuable for other countries.

Exploring the Driving Factors that Influence the Design, Function, and Use of Urban Wetlands in the United Kingdom

This paper aimed to investigate the driving factors for the creation of urban wetlands and their functions and uses. A mixed methods approach was used, comprising an online survey for the general public and structured interviews with four urban wetland 'experts'. Quantitative data was obtained from the survey, and cross tabulation was used to analyse relationships between variables. Thematic analysis was used for the qualitative data from the interviews. It was found that one of the urban wetlands was created for flood control and to create an amenity space, whilst the driving factors for the other three urban wetlands were associated with biodiversity and habitat creation, which was also perceived as the most important function of an urban wetland from the survey participants. Three themes emerged from the thematic analysis: 'wildlife conservation interest'; 'landscape character development'; and 'urban wetland as an amenity space'. The survey found that participants perceived climate resiliency as an important function of wetlands, despite this not being a driving factor for the four wetlands in the interviews. Survey participants would be willing to invest time in visiting a non-local wetland landscape to encounter nature and contribute to their quality of life and wellbeing. The results of this research may be useful to inform the planning, design and management of urban wetlands as they evolve towards being a multi-use spaces. More education and awareness are needed about the benefits of these landscapes to wildlife, the environment and local communities.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13157-022-01610-1.

Predicting wetland area and water depth in Barind plain of India

The present study attempts to delineate wetlands in the lower Tangon river basin in the Barind flood plain region using spectral water body extraction indices. The main objectives of this present study are simulating and predicting wetland areas using the advanced artificial neural network-based cellular automata (ANN-CA) model and water depth using statistical (adaptive exponential smoothing) as well as advanced machine learning algorithms such as Bagging, Random Subspace, Random Forest, Support vector machine, etc. The result shows that RmNDWI and NDWI are the representative wetland delineating indices. NDWI map was used for water depth prediction. Regarding the prediction of wetland areas, a remarkable decline is likely to be identified in the upcoming two decades. The small wetland patches away from the master stream are expected to dry out during the predicted period, where the major wetland patches nearer to the master stream with greater water depth are rather sustainable, but their depth of water is predicted to be reduced in the next decades. All models show satisfactory performance for wetland depth mapping, but the random subspace model was identified as the best-suited water depth predicting method with an acceptable prediction accuracy (root mean square error <0.34 in all the years) and the machine learning models explored better result than adaptive exponential smoothing. This recent study will be very helpful for the policymakers for managing wetland landscape as well as the natural environment.

A Typology of Nature-Based Solutions for Sustainable Development: An Analysis of Form, Function, Nomenclature, and Associated Applications

This study presents a typology of nature-based solutions (NbS), addressing the need for a standardized source of definitions and nomenclature, and to facilitate communication in this interdisciplinary field of theory and practice. Growing usage of the umbrella phrase ‘nature-based solutions’ has led to a broad inclusion of terms. With the diversity of terminology used, the full potential of NbS may be lost in the confusion of misapplied terms. Standardization and definition of commonly used nature-based nomenclature are necessary to facilitate communication in this rapidly expanding field. Through objective systemization of applications, functions, and benefits, NbS can be embraced as a standard intervention to address societal challenges and support achievement of the UN SDGs.

New integrated hydrologic approach for the assessment of rivers environmental flows into the Urmia Lake

Recent research has greatly focused on the environmental water supplement of rivers individually and independently. However, a comprehensive and integrated view of all rivers in the basin is simultaneously required in closed basins leading to lakes and wetlands. This has affected Lake Urmia, which is the second largest saltwater lake in the world. It has been in danger of drying up in recent years as a result of not allocating the required environmental flow (e-flow) due to the increase in water resource consumption in the agricultural sector and climate changes. In this study, a method derived from the flow duration curve shifting (FDCS) method is presented in addition to explaining the possibility of providing the e-flow of rivers leading to the lake. The method can make the least amount of change in the hydrological characteristics of rivers while providing the volume of required water by the ecosystem of lakes or downstream wetlands. Unlike the conventional method which presents the results on a monthly basis, the above-mentioned method is based on daily data of hydrometric stations and can calculate the amount of the environmental requirement of rivers in real-time according to the upstream inlet of the river. This method has been used in the Urmia Lake basin. According to the results, it can provide the environmental requirement of the lake by allocating 70.5% of the annual flow of rivers and thus can save the lake and the ecosystem of the region from the current critical conditions.

Wetland Construction, Restoration, and Integration: A Comparative Review

In response to the global loss and degradation of wetland ecosystems, extensive efforts have been made to reestablish wetland habitat and function in landscapes where they once existed. The reintroduction of wetland ecosystem services has largely occurred in two categories: constructed wetlands (CW) for wastewater treatment, and restored wetlands (RW) for the renewal or creation of multiple ecosystem services. This is the first review to compare the objectives, design, performance, and management of CW and RW, and to assess the status of efforts to combine CW and RW as Integrated Constructed Wetlands (ICW). These wetland systems are assessed for their ecological attributes and their relative contribution to ecosystem services. CW are designed to process a wide variety of wastewaters using surface, subsurface, or hybrid treatment systems. Designed and maintained within narrow hydrologic parameters, CW can be highly effective at contaminant transformation, remediation, and sequestration. The ecosystem services provided by CW are limited by their status as high-stress, successionally arrested systems with low landscape connectivity and an effective lifespan. RW are typically situated and designed for a greater degree of connection with regional ecosystems. After construction, revegetation, and early successional management, RW are intended as self-maintaining ecosystems. This affords RW a broader range of ecosystem services than CW, though RW system performance can be highly variable and subject to invasive species and landscape-level stressors. Where the spatial and biogeochemical contexts are favorable, ICW present the opportunity to couple CW and RW functions, thereby enhancing the replacement of wetland services on the landscape.

Obligations of Researchers and Managers to Respect Wetlands: Practical Solutions to Minimizing Field Monitoring Impacts

Research and field monitoring can disturb wetland integrity. Adoption of ethical field practices is needed to limit monitoring induced stressors such as trampling, non-native seed and invertebrate dispersal, and disease and fungal spread. We identify a linear pathway of deterioration highlighting stressors that can progress to cumulative impacts, consequences, and losses at the site scale. The first step to minimize disturbance is to assess and classify the current ecosystem quality. We present a tiered framework for wetland classification and link preventative measures to the wetland tier. Preventative measures are recommended at various intensities respective to the wetland tier, with higher tiered wetlands requiring more intense preventative measures. In addition, preventative measures vary by time of implementation (before, during, and after the wetland visit) to mitigate impacts at various temporal scales. The framework is designed to increase transparency of field monitoring impacts and to promote the adoption of preventative measures. Implementing preventative measures can build accountability and foster a greater appreciation for our roles as researchers and managers in protecting wetlands.

Constructed Wetlands as Nature-Based Solutions in the Post-COVID Agri-Food Supply Chain: Challenges and Opportunities

The COVID-19 crisis has highlighted the interchangeable link between human and nature. The health and socioeconomic impacts of COVID-19 are directly or indirectly linked to the natural environment and to the way that agri-food systems interact with nature. Although the pandemic continues to evolve and there are still many uncertainties, important issues about the future of the agri-food sector and the need for a sustainable and environmentally friendly reformation are beginning to arise in society. Nature-based Solutions (NbSs) encompass a broad range of practices that can be introduced in the agri-food supply chain and address multiple environmental challenges of the COVID-19 and post-COVID-19 era while providing economic and societal benefits. In this perspective, the design and establishment of multifunctional constructed wetlands as NbSs opens a portfolio of eco-innovative options throughout the agri-food supply chain, offering a realistic and promising way towards the green regeneration of the post-COVID-19 economy and the welfare of society. The aim of this work is to explore the potential role of constructed wetlands as Nature-based Solutions in the agri-food supply chain of the forthcoming post-COVID-19 era. More specifically, this work aims to reveal application opportunities of constructed wetlands in the different segments of the agri-food supply chain, identify linkages with societal challenges and EU policies, and discuss their potential limitations, future challenges, and perspectives.

The Gavkhouni Wetland Dryness and Its Impact on Air Temperature Variability in the Eastern Part of the Zayandeh-Rud River Basin, Iran

The Gavkhouni wetland provides many environmental and economic benefits for the central region of Iran. In recent decades, it has completely dried up several times with substantial impacts on local ecosystems and climate. Remote sensing-based Land Surface Temperature (LST), Normalized Difference Water Index (NDWI) and Normalized Difference Vegetation Index (NDVI) in combination with in-situ data were used to investigate the trend of the Gavkhouni wetland dryness and the associated impact on the variability of local air temperature. The results indicate that the wetland has increasingly experienced drier conditions since the year 2000. The wetland was almost completely dry in 2009, 2011, 2015 and 2017. In addition, the results show that Gavkhouni wetland dryness has a significant impact on local climate, increasing the mean seasonal air temperature by ~1.6 °C and ~1 °C in spring and summer, respectively. Overall, this study shows that remote sensing imagery is a valuable source for monitoring dryness and air temperature variations in the region. Moreover, the results provide a basis for effective water allocation decisions to maintain the hydrological and ecological functionality of the Gavkhouni wetland. Considering that many factors such as latitude, cloud cover, and the direction of prevailing winds affect land surface and air temperatures, it is suggested to use a numerical climate model to improve a regional understanding of the effects of wetland dryness on the surrounding climate.

Aquatic Vegetation Loss and Its Implication on Climate Regulation in a Protected Freshwater Wetland of Po River Delta Park (Italy)

Aquatic vegetation loss caused substantial decrease of ecosystem processes and services during the last decades, particularly for the capacity of these ecosystems to sequester and store carbon from the atmosphere. This study investigated the extent of aquatic emergent vegetation loss for the period 1985–2018 and the consequent effects on carbon sequestration and storage capacity of Valle Santa wetland, a protected freshwater wetland dominated by Phragmites australis located in the Po river delta Park (Northern Italy), as a function of primary productivity and biomass decomposition, assessed by means of satellite images and experimental measures. The results showed an extended loss of aquatic vegetated habitats during the considered period, with 1989 being the year with higher productivity. The mean breakdown rates of P. australis were 0.00532 d−1 and 0.00228 d−1 for leaf and stem carbon content, respectively, leading to a predicted annual decomposition of 64.6% of the total biomass carbon. For 2018 the carbon sequestration capacity was estimated equal to 0.249 kg C m−2 yr−1, while the carbon storage of the whole wetland was 1.75 × 103 t C (0.70 kg C m−2). Nonetheless, despite the protection efforts over time, the vegetation loss occurred during the last decades significantly decreased carbon sequestration and storage by 51.6%, when comparing 2018 and 1989. No statistically significant effects were found for water descriptors. This study demonstrated that P. australis-dominated wetlands support important ecosystem processes and should be regarded as an important carbon sink under an ecosystem services perspective, with the aim to maximize their capacity to mitigate climate change.

The effects of biochar/compost for adsorption behaviors of sulfamethoxazole in amended wetland soil

Biochar and compost were two common amendments for the polluted soil. However, few studies were conducted to study the sorption of organic pollutants on combined biochar-compost and the relative adsorption mechanisms in mixed soil. The work had studied the adsorption and desorption behaviors of sulfamethoxazole (SMX) onto wetland soil after amended with biochar and/or compost. Moreover, the physicochemical and morphology properties of biochar/compost and amended soils were analyzed to discuss the relative adsorption mechanisms. Studies showed that the adsorption capacity of amended soils increased with the total amount of biochar or/and compost added, which was positively related to SOM, CEC, and EC of amended soils, but had nothing to do with the type of additives. Compared with the compost-treated treatments, the biochar-treated treatments generally achieved lower desorption rates, which also had demonstrated both different adsorption mechanisms. Pore filling and hydrophobic partitioning were the main adsorption mechanisms for biochar and compost, respectively. Though biochar owned developed pore structure, however, pore-filling of biochar was overwhelmingly weakened due to pore-blocking in mixed soils. Hence, in soil environment, compost is a kind of a more desirable amendment than biochar in absorbing and degrading organic pollutants.

Comparing Wetland Ecosystems Service Provision under Different Management Approaches: Two Cases Study of Tianfu Wetland and Nansha Wetland in China

The largest blue-green infrastructures in industrialized, urbanized and developed regions in China are often multiuse wetlands, located just outside growing urban centers. These areas have multiple development pressures while providing environmental, economic, and social benefits to the local and regional populations. Given the limited information available about the tradeoffs in ecosystem services with respect to competing wetland uses, wetland managers and provincial decision makers face challenges in regulating the use of these important landscapes. In the present study, measurements made by citizen scientists were used to support a comparative study of water quality and wetland functions in two large multiuse wetlands, comparing areas of natural wetland vegetation, tourism-based wetland management and wetland agriculture. The study sites, the Nansha and Tianfu wetlands, are located in two of the most urbanized areas of China: the lower Yangtze River and Pearl River catchments, respectively. Our results indicated that the capacity of wetlands to mitigate water quality is closely related to the quality of the surrounding waters and hydrological conditions. Agricultural areas in both wetlands provided the lowest sediment and nutrient retention. The results show that the delivery of supporting ecosystem services is strongly influenced by the location and use of the wetland. Furthermore, we show that citizen scientist-acquired data can provide fundamental information on quantifying these ecosystem services, providing needed information to wetland park managers and provincial wetland administrators.

Wetlands Cool Land Surface Temperature in Tropical Regions but Warm in Boreal Regions

Wetlands play a critical role in global hydrological and biogeochemical cycles. Regulating the regional climate is one of the most important ecosystem services of natural wetlands. However, the impact of wetlands on local temperature on the global scale and the attribution is still unclear. This study utilizes the satellite-based products (land surface temperature (LST), albedo, and evapotranspiration (ET)) to evaluate the difference in LST between wetlands and their adjacent landcover types and the possible drivers. Here we show that on average for the whole year, wetlands have a cooling effect in tropical regions, but have a warming effect in boreal regions. The impacts of wetlands on LST show great seasonality in the boreal regions; i.e., the wetlands have a warming effect in winter but a cooling effect in summer. The difference in albedo and ET between wetlands and the other landcover types only interprets 30% of temporal variation of the difference in LST. Due to the large water storage in wetlands, the ground heat flux (G) may interpret the rest of the impact, absorbing energy in summer and releasing energy in winter in wetlands, which has often been neglected in previous studies. Our results indicate that it is critical to comprehensively consider the effects of wetland restoration in different regions to realize potential climatic benefits in the future.

Disentangling Responses of the Subsurface Microbiome to Wetland Status and Implications for Indicating Ecosystem Functions

In this study, we analyzed microbial community composition and the functional capacities of degraded sites and restored/natural sites in two typical wetlands of Northeast China-the Phragmites marsh and the Carex marsh, respectively. The degradation of these wetlands, caused by grazing or land drainage for irrigation, alters microbial community components and functional structures, in addition to changing the aboveground vegetation and soil geochemical properties. Bacterial and fungal diversity at the degraded sites were significantly lower than those at restored/natural sites, indicating that soil microbial groups were sensitive to disturbances in wetland ecosystems. Further, a combined analysis using high-throughput sequencing and GeoChip arrays showed that the abundance of carbon fixation and degradation, and ~95% genes involved in nitrogen cycling were increased in abundance at grazed Phragmites sites, likely due to the stimulating impact of urine and dung deposition. In contrast, the abundance of genes involved in methane cycling was significantly increased in restored wetlands. Particularly, we found that microbial composition and activity gradually shifts according to the hierarchical marsh sites. Altogether, this study demonstrated that microbial communities as a whole could respond to wetland changes and revealed the functional potential of microbes in regulating biogeochemical cycles.

Advances in the Monitoring of Algal Blooms by Remote Sensing: A Bibliometric Analysis

Since remote sensing of ocean colour began in 1978, several ocean-colour sensors have been launched to measure ocean properties. These measures have been applied to study water quality, and they specifically can be used to study algal blooms. Blooms are a natural phenomenon that, due to anthropogenic activities, appear to have increased in frequency, intensity, and geographic distribution. This paper aims to provide a systematic analysis of research on remote sensing of algal blooms during 1999–2019 via bibliometric technique. This study aims to reveal the limitations of current studies to analyse climatic variability effect. A total of 1292 peer-reviewed articles published between January 1999 and December 2019 were collected. We read all the literature individually to build a database. The number of publications increased since 2004 and reached the maximum value of 128 in 2014. The publications originated from 47 countries, but the number of papers published from the top 10 countries accounted for 77% of the total publications. To be able to distinguish between climate variability and changes of anthropogenic origin for a specific variable is necessary to define the baseline. However, long-term monitoring programs of phytoplankton are very scarce; only 1% of the articles included in this study analysed at least three decades and most of the existing algal blooms studies are based on sporadic sampling and short-term research programs.