Eutrophication and flood risk are pressing issues of ecological and societal relevance. A key driver of eutrophication is the use of nitrogen (N) fertiliser in agriculture, resulting in N exports from land to water. Climate change increases the risk of flood events which can increase N exports and further worsen eutrophication. Created wetlands in agricultural areas are recognised as effective nutrient sinks, and the flood attenuating capabilities of wetlands are well established. However, the combination of these two ecosystem services in agricultural landscapes is understudied. This study examines how water flow buffering in created wetlands affects N removal and greenhouse gas (GHG) emissions. The study was performed in experimental wetlands of different designs (depth and size) subjected to intermittent or permanent flooding (gradual emptying between inflow events or a constant water level). Intermittently flooded wetlands removed less N than permanently flooded wetlands, especially during no-flow periods. The largest difference was found among deep wetlands, where the average N removal across the study was 0.19 g m-2 d-1 (25 %) in intermittently flooded wetlands and 0.27 g m-2 d-1 (38 %) in permanently flooded wetlands. No differences in the aqueous concentrations of N2O or CH4 were observed between wetlands with high or low water storage capacity, thus indicating similar emissions. This study highlights a risk of lowered N removal in created wetlands designed for flood attenuation. Further studies are needed on synergies and trade-offs when aiming to combine flood attenuation and N removal in created wetlands.

Wetland management maintains nitrogen (N) removal capacity in mature and overgrown constructed wetlands (CWs). We evaluated whether CW management by macrophyte harvesting, and subsequent installation of woodchips-based floating beds (WFBs) planted with Glyceria maxima and Filipendula ulmaria improved N removal. In sixteen heavily overgrown experimental CWs, we applied four treatments: i) only macrophyte harvesting, ii) 5% of the harvested-CW surface covered with WFBs, iii) 20% WFBs cover, and iv) a control treatment (heavily overgrown). N removal was determined in all wetlands at nine occasions. Plant biomass accrual, N assimilation, and denitrification genes nirS, nirK, nosZI and nosZII on plant roots and woodchips from WFBs were estimated. Macrophyte harvesting improved N removal of heavily overgrown CWs, whereas subsequent WFB installation only sometimes improved N removal. Mean N removal efficiencies (± standard deviation) overall were 41 ± 15 %, 45 ± 20 %, 46 ± 16 % and 27 ± 8.3 % for treatments i to iv, respectively. Relative biomass production, root length and root surface area for G maxima (mean ± standard deviation: 234 ± 114 %, 40 ± 6.5 cm, 6308 ± 1059 cm2g-1, respectively) were higher than those for F. ulmaria (63 ± 86 %, 28 ± 12 cm, 3131 ± 535 cm2g-1, respectively) whereas biomass N assimilation was higher for F. ulmaria (1.8 ± 0.9 gNm-2 of WFB) than for G. maxima (1.3 ± 0.5 gNm-2 of WFB). Denitrification gene abundance was higher on plant roots than on woodchips while G. maxima hosted higher root denitrification gene abundance than F. ulmaria. We conclude that macrophyte harvesting improves N removal in heavily overgrown CWs. WFBs installation has the potential to support plant growth and denitrification in surface-flow constructed wetlands. Further studies need to evaluate the long-term effects of macrophyte harvesting and WFB installation on N removal in CWs.

Wetlands in agricultural areas mitigate eutrophication by intercepting nutrient transports from land to sea. The role of wetlands for nutrient removal may become even more important in the future because of the expected increase in agricultural runoff due to climate change. Because denitrification is temperature dependent, wetland nitrogen (N) removal usually peaks during the warm summer. However, climate change scenarios for the northern temperate zone predict decreased summer and increased winter flows. Future wetlands may therefore shift towards lower hydraulic loading rate and N load during summer. We hypothesised that low summer N loads would decrease annual wetland N removal and tested this by examining 1.5-3 years of continuous N removal data from created agricultural wetlands in two regions in southern Sweden (East and West) during different periods. West wetlands showed relatively stable hydraulic loads throughout the year, whereas East wetlands had pronounced no-flow periods during summer. We compared East and West wetlands and tested the effects of several variables (e.g., N concentration, N load, hydraulic load, depth, vegetation cover, hydraulic shape) on annual absolute and relative N removal. We found no difference in annual N removal between East and West wetlands, even though summer N loads were lower in East than in West wetlands. A possible explanation is that stagnant water conditions in East wetlands suppressed decomposition of organic matter during summer, making more organic matter available for denitrification during winter. Absolute N removal in all wetlands was best explained by N load and hydraulic shape, whereas relative N removal was best explained by emergent vegetation cover and hydraulic shape. This study highlights the importance of design and location of agricultural wetlands for high N removal, and we conclude that wetlands in a future climate may remove N from agricultural runoff as efficiently as today.

The agricultural sector has a critical role in creating social and environmental value of natural resources in addition to its traditional role of creating economic value by supplying food to the ever-increasing world population. In fulfilling this dual role, the agricultural sector often faces competing pressures: to operate financially profitable businesses and to create, maintain, and benefit from ecosystem services (ES) in their operations. This paper analyses these pressures in an examination of drivers and barriers to the initiation of the business model innovation process for sustainability (BMIpfS) as perceived by ten agricultural business managers who operate farms in southern Sweden. The paper explores the interplay between managerial cognition and business decisions as revealed in semi-structured interviews. The new ES in focus connect to radical land-use change, paludiculture, as used in the rewetting of farmland intended to reduce the greenhouse gas emissions that drained peat soil causes. The paper contributes to the literature by identifying drivers and barriers that moderates the initiation of the BMIpfS. Although the managers acknowledge the importance of long-term, sustainable social, and environmental value creation, they have grave doubts about the profitability of activities associated with the preservation of peat soils and connected ES. These managers would benefit from taking a more proactive, long-term approach to business model changes for sustainability and from acquiring more knowledge about market demand for sustainability-oriented ES. Successful facilitation and implementation of knowledge transfer and government subsidies that support ES could improve the turning of profits based on sustainable value creation.

Efforts to mitigate greenhouse gas (GHG) emissions are receiving increased attention among governmental and commercial actors. In recent years, the interest in paludiculture, i.e. the use of rewetted peatlands, has grown because of its potential to reduce GHG emissions by stopping soil decomposition. Moreover, cultivating wetland plants on rewetted peatlands for bioenergy production that replaces fossil fuels in the transport sector, can contribute to additional GHG emission reductions. In this study, an analysis of literature data was conducted to obtain data on GHG emissions (CO2 and CH4) and biomass production from rewetted peatlands cultivated with two different wetland plant species: Phragmites australis (Pa) and Typha latifolia (Tl). In addition, a biogas experiment was carried out to investigate the biomethane yield of Pa and Tl biomass, and the reduction of global warming potential (GWP) by using biomethane as vehicle fuel. The results show that peatland rewetting can be an important measure to mitigate the GWP as it reduces GHG emissions from the soil, particularly on a 100-year timescale but also to some extent on a 20-year timescale. More specifically, rewetting of 1 km2 of peatland can result in a GWP reduction corresponding to the emissions from ±2600 average sized petrol cars annually. Growing Pa on rewetted peatlands reduces soil GHG emissions more than growing Tl, but Pa and Tl produced similar amounts of biomass and biomethane per land area. Our study concludes that Pa, because of a more pronounced GWP reduction, is the most suitable wetland plant to cultivate after peatland rewetting.

Restored and constructed semi-natural wetlands are increasingly used in the agricultural landscape to intercept nutrients from surface waters. Vegetated surface-flow wetlands remove more nitrogen (N) than those without vegetation. However, changes in N removal over time as differently vegetated wetlands progress from early successional stages to mature systems are less investigated. We monitored three different types of initial planting over the course of 12 years. with the aim to examine how planting of newly constructed wetlands affects longterm N removal. All our data were collected in an experimental wetland facility in south-western Sweden. The facility consists of 18 identical small (ca. 25 m(2)) surface-flow wetlands, simulating semi-natural wetlands in an agricultural landscape. Initially, the 18 wetlands were randomly divided into three treatments (vegetation types) with six replicates each and planted with (1) emergent vegetation, (2) submerged vegetation and (3) no vegetation for free development. Vegetation succession afterwards progressed uninhibited in all wetlands. Emergent vegetation wetlands initially removed more N than both submerged vegetation and free development wetlands. We found that N removal in submerged vegetation and free development wetlands increased with ecosystem age, whereas N removal in emergent vegetation wetlands did not. N removal in all three vegetation types converged when the wetlands reached a more mature state, around 8 years after wetland construction. However, although all wetlands contained emergent vegetation in year 8, the proportion of emergent vegetation cover and vegetation composition still differed substantially between wetland types. Our study indicates that it is not the cover of emergent vegetation per se which promotes higher N removal in more mature wetlands, but the maturation process itself; mature wetlands despite differing emergent vegetation coverage achieved equally high N removal. In conclusion, once wetlands reach maturity. beneficial effects of initial planting on N removal disappear. (C) 2020 The Authors. Published by Elsevier B.V.

Phragmites australis, Typha latifolia, T. angustifolia and Arundo donax are tall wetland graminoids with the potential to replace fossil fuels under sustainable cultivation conditions. We investigated the biomethane (CH4) production of these four species, including four different genotypes of P. australis, which represent the high intraspecific diversity of European reed. All plants were grown under three different macronutrient supplies (no nutrients added, an equivalent of 75 kg N ha−1 year−1 added and an equivalent of 500 kg N ha−1 year−1 added). Biomethane production was measured in four independent batch digestion tests. Across all experiments, fertilization regime had little effect on CH4 yield, which was on average 222 ± 31 L kg−1 volatile solids (VS). The lowest yield was produced by T. angustifolia (140 L kgVS−1) receiving no nutrients, while the highest yield was produced by A. donax (305 L kgVS−1) in the highest nutrient treatment. The intraspecific diversity of P. australis did not affect biomethane production. All P. australis genotypes produced on average 226 ± 19 L CH4 kgVS−1, which, although high, was still lower than conventional biogas species. The biomass production of P. australis was less increased by fertilization than that of Typha sp. and A. donax, but all species had similar biomass without fertilization.

Though the existence of cultural ecosystem services is dependent on people's activities and experiences, these services are still commonly assessed using top-down approaches. In this study, appraisal theory and research into human responses to natural environments formed the basis of a systematic multilevel investigation of appraisals of created wetland areas. The aim was to explore how appraisals could be used as a bottom-up approach to assessing the perceived contribution of wetland areas s to people's quality of life (QoL). In total, 111 participants assessed environmental perceptions, affective experiences, and restorative potentials on site at three wetlands in Sweden. The results indicate that wetland areas and specific places with different ecological functions within these areas were appraised significantly differently. Moreover these places were perceived to support various QoL aspects to different degrees. Concepts and methods tested here give environmental planners hands-on tools for facilitating communication with expected users about the cultural ecosystem services of created wetland areas.

Excess nitrogen (N) from agricultural runoff is a cause of pollution in aquatic ecosystems. Created free water surface (FWS) wetlands can be used as buffering systems to lower the impacts of nutrients from agricultural runoff. The purpose of this paper was to evaluate critical factors for N removal in FWS wetlands receiving high nitrate (NO3−) loads from agriculture. The study was performed in 12 experimental FWS wetlands in southern Sweden, receiving drainage water from an agricultural field area. The effects of water depth (mean depth of 0.4 m and 0.6 m, respectively) and phosphorus (P) availability (with or without additional P load) were investigated from July to October. The experiment was performed in a two-way design, with three wetlands of each combination of depth and P availability. The effects of P availability on the removal of NO3− and total N were strongly significant, with higher absolute N removal rates per wetland area (g m−2 day−1) as well as temperature-adjusted first-order area-based removal rate coefficients (Kat) in wetlands with external P addition compared to wetlands with no addition. Further, higher N removal in deep compared to shallow wetlands was indicated by statistically significant differences in Kat. The results show that low P availability may limit N removal in wetlands receiving agricultural drainage water. Furthermore, the results support that not only wetland area but also wetland volume may be important for N removal. The results have implications for the planning, location, and design of created wetlands in agricultural areas.

Initial planting of created wetlands is common practice in order to, for instance, improve nitrogen (N) removal. It has been shown that vegetated surface-flow wetlands remove more N than non-vegeta ...

Wetlands in urban areas will be crucial to counteract the effects of climate change, for example, by improving flood protection and regulating local climate. To gain acceptance for larger-scale creation of wetlands, total values must be identified and revealed. Provisioning and regulating ecosystem services can be described as the quantitative effect, but cultural ecosystem services require other assessments. This study sought to determine whether peri-urban and urban wetland areas contribute to the well-being and quality of life of nearby residents, and to capture their value relative to two other types of green areas (i.e., parks and urban forests). A postal questionnaire survey, based on validated environmental psychology instruments, was distributed to residents in three municipalities with wetland areas of different structures and locations. In these municipalities, respondents (n = 474; response rate = 40%) reported that the wetland area contributed to several quality-of-life aspects, such as encountering nature and experiencing beauty. The areas also facilitated activities that support well-being, were perceived to have high restorative qualities, and evoked positive affective responses. All wetland areas were rated high on most of the measured concepts, but their value relative to other green areas differed possibly depending on the accessibility of the wetland and the availability of other green areas. The location and extent to which the wetland area was integrated in the residential area determined what quality-of-life aspects were most satisfied. Wetland areas can be ascribed cultural ecosystem service values based on how residents perceive their contribution to their quality of life. These values can be added to those of provisioning and regulating ecosystem services, forming the basis for planning urban environments.

There are many challenges that need to be addressed if the far reaching objectives on high environmental status as required in the EU Water Framework Directive and the Marine Strategy Framework Directive will be met in the Baltic Sea Region within the next decade. For wastewater treatment plants (WWTP) this implies, in spite of the many improvements made during the last decade, development and introduction of new technology to further reduce eutrophying compounds, hazardous chemicals and pharmaceuticals. Constructed wetlands when properly designed and operated have been shown to be robust systems with low energy requirements that may not only reduce many types of pollutants but may also provide many additional ecosystem services beyond requirements generally imposed by authorities. For example, they may support and enhance biodiversity and be used to convert brownfield areas in urban landscapes to recreational areas. Reduced cost is possible if treated water is reused in industry or for irrigation. In a project, supported by the Swedish Institute, a group of scientists, a water company and water using industry has together with local authorities through workshops, field studies and literature studies worked on finding a general first recommendation on design and operation. In this paper we will present the scientific rational and legal constraints for the general design and operation of a wetland system for post-tertiary treatment of waste water from WWTPs using Gdańsk as an example. The proposal includes a first part, which mainly will be focusing on pollutant and pathogen removal using particle traps and a HSSF wetland on land owned by the WWTP and a second part consisting of a FWS wetland which, in addition to further polishing the water, will enhance biodiversity and provide recreational areas on derelict land owned by the city.

During 2007–2013, the Swedish Board of Agriculture granted support within a national program to about 1000 wetlands, corresponding to a 5300-hectare wetland area, with the dual goal to remove nutrients from water and to improve biodiversity in agricultural landscapes. The aim of the present study was to compare the effects on nutrient transports that are realized within the national program to what could be obtained with the same area of wetlands if location and design of wetlands were optimized. In single, highly nutrient-loaded wetlands, a removal of around 1000 kg nitrogen and 100 kg phosphorus per hectare wetland area and year was estimated from monitoring data. Statistical models were developed to estimate the overall nutrient removal effects of wetlands created within the national program. Depending on model, the effect of the national program as a whole was estimated to between 27 and 38 kg nitrogen and between 2.7 and 4.5 kg phosphorus per hectare created wetland area and year. Comparison of what is achieved in individual wetlands to what was achieved in the national program indicates that nutrient removal effects could be increased substantially in future wetland programs by emphasising location and design of wetlands.

Seven constructed wetlands (0.05-0.69 ha), situated in agricultural catchments (22-267 ha) in the south of Sweden, were studied for two years with two aims: to (i) quantify their function as sinks for particles and phosphorus (P) lost from the catchments, and (ii) investigate to what degree catchment and wetland characteristics and modeled loads (using hydrochemical catchment models) could be used to explain differences in retention between the wetlands. The wetland areas ranged from 0.04 to 0.8% of the respective catchment area, and they were situated in areas dominated by fine-textured soils with relatively high P losses and the main proportion of P transported in particulate form. Net P and particle retention were estimated during two years from annual accumulation of particles on sedimentation plates (40 x 40 cm) on the bottom of the wetlands.There was an annual net retention of particles and P, but with a large variation (for particles 13-108 t ha(-1) yr(-1) and for P 11-175 kg ha(-1) yr(-1)), both between wetlands and between years. The difference between the two years was larger than the difference in mean P retention between the seven wetlands. There was a positive relationship between P and particle retention and three catchment factors, i.e. P status (P-AL) of agricultural soils, average slope in the catchments and the livestock density, and a negative relationship with the agricultural soil clay content. In addition, there was a positive relationship with the wetland length: width ratio. Contrary to expectations, neither the modeled hydraulic load nor P load was significantly correlated with the measured particle and P retention. There was also a positive relationship between P concentration in the sediment and soil P status in the catchment. The results imply that considerable errors are introduced when down-scaling modeled regional nutrient losses to estimate the P loads to small wetlands in agriculturally dominated catchments. A more qualitative approach, using catchment characteristics for identification of hot-spot fields, may be equally good to identify suitable locations for constructed wetlands to reduce diffuse P loads. (C) 2014 Elsevier B.V. All rights reserved.

I denna rapport sammanstalls och analyseras tidigare matningar av avskiljning av fosfor och kvave i anlagda vatmarker. Resultaten indikerar hur hog fosfor­ och kvaveavskiljning som kan uppnas i anl ...

Data from seven constructed wetlands (CWs) in the south of Sweden were analyzed to investigate the effects of water flow and season on inflow phosphorus (P) concentrations and temporal P retention variations in CWs receiving runoff from arable land. The form of P (dissolved or particulate) during different water flows (high and low) and seasons (warm and cold) was investigated using the results of total P (TP) and phosphate analyzed in grab samples that had been collected regularly or occasionally during two to nine years, along with continuous water flow measurements.The form of inflow and outflow P (particulate or dissolved P) differed between CWs, and also varied with season and flow. For instance, in three of the CWs, particulate P (PP) dominated the inflow during the cold period with high flow, while during the other periods the proportion of PP was approximately 50%. In one CW situated in a catchment with high clay content, PP dominated both inflow and outflow at all times. The average clay content in catchment top soils was positively correlated to the flow-weighted inflow TP concentrations.In three CWs receiving runoff through drainage pipes, the relationship between TP concentrations (TPin) and water flow was positive, both during high and low flow, and during warm and cold period. However, in four CWs that received surface water runoff, the relationship between TPin and water flow was positive during high flow periods (i.e. the 25% sampling occasions with the highest flow), and during low flow and warm period, the relationship was negative in these four wetlands, indicating either anoxic stagnant water upstream or influence from rural wastewater.The temporal dynamics of P concentrations mean that in some of the CWs, the main part of the annual P retention may occur during a few days with high water flows. The correlation between concentration and water flow suggests that the water sampling strategy may have a considerable impact on retention estimates, as exemplified by some calculation examples. (c) 2015 Elsevier B.V. All rights reserved.

Measurements of removal of phosphorus and nitrogen in created wetlands in agricultural areas in Sweden have been compiled and analysed. The results indicate the level of phosphorus and nitrogen removal that can be achieved in created wetlands in agricultural areas in Sweden. The results have also been used to develop new models for calculating removal of phosphorus and nitrogen in created wetlands in which measurements have not been done. Finally, these models have been used to estimate the removal effects that can be expected in the wetlands that have received financial support within the Swedish Rural Develop­ ment Programme in 2007–2013, and how much the transport of phosphorus and nitrogen to the sea will decrease due to the creation of these wetlands.The new results show that phosphorus removal has been underestimated in earlier measurements as well as in models used in previous evaluations. In individual well designed and located wetlands, a removal of 100 kilo phosphorus and 1 000 kilo nitrogen per hectare wetland area and year can be obtained. The new results also indicate that it should be possible to achieve a removal of 50 kilo phosphorus and 500 kilo nitrogen per hectare wetland area and year in wetland creation programs prioritizing wetlands that are located and designed primarily for nutrient removal. The costs are estimated to 100 SEK per kilo phosphorus and 10 SEK per kilo nitrogen, if 50 percent of the costs are allocated to biodiversity and other ecosystem services.Model calculations based on a selection of representative wetlands within the Rural Development Programme were scaled up to the 5 261 hectare wetland area that have been granted financial support during 2007–2013. The evaluation show that the Rural Development Programme will result in a reduced transport to local waters­ heds of about 25 tons of phosphorus and 200 tons of nitrogen per year. Therefore, the transport to the sea will decrease with about 18 tons of phosphorus per year and about 170 tons of nitrogen per year, corresponding to 1.9 and 0.5 percent, respectively, of the transport to the sea from agricultural land.Creation of wetlands within the Rural Development Programme has thus resulted in significant decreases of transports of phosphorus and nitrogen to inland waters and the coastal sea. However, a comparison of removal per hectare wetland area and year between what has been achieved within the Rural Development Programme and in individual wetlands suggests that the effect could be substantially increased with a better location and design of wetlands.

Recently, there have been growing concerns about pharmaceuticals including antibiotics as environmental contaminants. Antibiotics of concentrations commonly encountered in wastewater have been suggested to affect bacterial population dynamics and to promote dissemination of antibiotic resistance. Conventional wastewater treatment processes do not always adequately remove pharmaceuticals causing environmental dissemination of low levels of these compounds. Using constructed wetlands as an additional treatment step after sewage treatment plants have been proposed as a cheap alternative to increase reduction of wastewater contaminants, however this means that the natural microbial community of the wetlands becomes exposed to elevated levels of antibiotics. In this study, experimental surface-flow wetlands in Sweden were continuously exposed to antibiotics of concentrations commonly encountered in wastewater. The aim was to assess the antibiotic removal efficiency of constructed wetlands and to evaluate the impact of low levels of antibiotics on bacterial diversity, resistance development and expression in the wetland bacterial community. Antibiotic concentrations were measured using liquid chromatography–mass spectrometry and the effect on the bacterial diversity was assessed with 16S rRNA-based denaturing gradient gel electrophoresis. Real-time PCR was used to detect and quantify antibiotic resistance genes and integrons in the wetlands, during and after the exposure period. The results indicated that the antibiotic removal efficiency of constructed wetlands was comparable to conventional wastewater treatment schemes. Furthermore, short-term treatment of the constructed wetlands with environmentally relevant concentrations (i.e. 100–2000ng×l−1) of antibiotics did not significantly affect resistance gene concentrations, suggesting that surface-flow constructed wetlands are well-suited for wastewater treatment purposes.

Constructed wetlands, have been used to decrease nitrogen transport from agricultural catchments to the coast of Sweden, while simultaneously contributing to increased species richness in the landscape. The purpose of this paper is to compile and evaluate data that have been produced in Sweden during some 20 years of using constructed wetlands as an environmental tool. To evaluate effects of different stated objectives for constructed wetlands within different national support systems we focus on nitrogen removal and bird and amphibian species richness. Continuous automatic water sampling for nitrogen removal measurements, during 1.5 to 10 years, has been performed in 7 constructed wetlands located in agricultural catchments in southern Sweden. Nitrogen removal per wetland area varied between wetlands but the results imply that an annual removal of at least 1000 kg N per ha wetland area can be achieved in individual wetlands. Data from the long-term monitoring of the 7 wetlands, together with nitrogen removal data in the literature, were used to model >150 randomly selected constructed wetlands. According to the modeling, the nitrogen removal per created wetland area varied markedly between different wetland creation programs and was generally considerably lower compared to what can be achieved in individual wetlands. Cost-efficiency of nitrogen removal in wetland creation programs can be increased considerably with improved planning and if other desired benefits (e.g. species richness) contribute to share the costs for wetland creation.The effects of constructed wetlands in Sweden on species number and populations of wetland birds and amphibians were large enough to positively affect the occurrence of species in the national red list, i.e. on a national population level. Species richness of wetland breeding birds in the constructed wetlands were relatively stable after 13 years, but different functional groups had very different succession pattern. The mean maximum breeding bird species number in the wetlands occurred after 3.8 years.Wetland birds and amphibians colonized constructed wetlands irrespective of the original objective of the wetland (nitrogen removal or biodiversity). However, some amphibian species showed preference for biodiversity wetlands. There were clear effects of wetland construction on the regional populations of non-wetland bird species. The maximum species number for a given wetland size was found to be higher than previously reported.The analyses show that wetland construction can be a cost effective method for decreasing transport of diffuse pollution from arable land, and that the wetlands are important for the species numbers and population sizes on all spatial scales. (C) 2013 Elsevier B.V. All rights reserved.

Bacteria play important roles in the transformation of nutrients in wetlands, but few studies have examined parameters affecting variation in bacterial community composition between wetlands. We co ...