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  • 1.
    Johannesson, K.
    et al.
    Linköping University.
    Tonderski, K.S.
    Linköping University.
    Wedding, B.
    Ekologgruppen i Landskrona AB.
    Weisner, S.E.B.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Phosphorus dynamics and retention in non-point source wetlands in southern Sweden2010Ingår i: Proceedings of the 12th International Water Association International Conference on Wetland Systems for Water Pollution Control: October 4-8, 2010 Venice, Italy. Volume 1 / [ed] Fabio Masi and J. Nivala, San Giovanni Valdarno: Palombi Editori , 2010, s. 493-494Konferensbidrag (Refereegranskat)
    Abstract [en]

    Seven constructed wetlands receiving diffuse pollution from agricultural land in the south of Sweden were investigated with respect to water flow patterns and phosphorus (P) dynamics. P retention was positive, and correlated to P load in all wetlands. However, there was a large variation in both specific and relative retention, both between wetlands and between years. Thus, the phosphorus retention in a specific wetland is difficult to predict using simple loadretention models. The water flow was correlated to P concentrations in most wetlands; however, there were some exceptions. For instance, one wetland showed a negative relationship between water flow and P concentration during summer, which indicated that other factors than the water flow determined the dynamics of P during this season. This investigation will provide a better understanding of factors affecting phosphorus retention in constructed wetlands, with further implications for wetland research and monitoring. Furthermore, the results can assist when formulating models for phosphorus removal in wetlands receiving nonpoint source runoff.

  • 2.
    Johannesson, Karin
    Linköping University, Linköping, Sweden.
    Analysis of phosphorus retention variations in constructed wetlands receiving variable loads from arable land2011Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 3.
    Johannesson, Karin M.
    et al.
    IFM Biology, Section Ecology, Linköping University, Linköping, Sweden.
    Andersson, Jonas L.
    WRS Uppsala AB, Uppsala, Sweden.
    Tonderski, Karin S.
    IFM Biology, Section Ecology, Linköping University, Linköping, Sweden.
    Efficiency of a constructed wetland for retention of sediment-associated phosphorus2011Ingår i: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 674, nr 1, s. 179-190Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A constructed wetland (2.1 ha; 2% of catchment area) in southeast Sweden, in a catchment with 35% arable land on clay soils, was investigated with respect to phosphorus (P) retention, focusing on particulate P (PP) and sediment accretion. The aims were to (i) estimate P retention and identify the dominating retention processes; (ii) investigate how well estimates of P retention based on inflow-outflow measurements compared with the amount of P accumulated in the sediment. In- and outflow of P was measured during 4 years with continuous flow measurements and flow-proportional weekly composite samples. P in the accumulated sediment was estimated based on core samples and analyzed using sequential fractionation. Total P load during 4 years was 65 kg ha-1 and intensive sampling events detected 69% as PP. Based on inflow-outflow estimates the mean P retention was 2.8 kg ha-1 year-1, or 17%, but the amount of P accumulated in the inlet zone equated 78% of the TP load. This discrepancy showed the need to add studies of sediment accumulation to inflow-outflow estimates for an improved understanding of the P retention. The dominating P forms in the sediment were organic P (38%) and P associated with iron or aluminum (39%), i.e., potentially mobile forms. In areas colonized by Typha latifolia, the amount of P in the upper sediment layer (390 kg) was more than double the total P load of 136 kg. Cycling and release in those areas is a potential source of P that deserves further attention. © 2011 Springer Science+Business Media B.V.

  • 4.
    Johannesson, Karin M.
    et al.
    IFM Ecology, Linköping University, Linköping, Sweden.
    Kynkäänniemi, Pia
    Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ulén, Barbro
    Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Weisner, Stefan E.B.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Tonderski, Karin S.
    IFM Ecology, Linköping University, Linköping, Sweden.
    Clay-bound phosphorus retention in wetlands: a catchment comparison2010Ingår i: 6th International Phosphorus Workshop (IPW6): Towards a sustainable control of diffuse P loss: risk, monitoring, modelling, and mitigation options : Book of Abstracts, 2010, s. 127-127Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Ten constructed wetlands, situated in agricultural areas in the south of Sweden, are investigated for phosphorus (P) retention and factors affecting the efficiency. These wetlands are situated in areas dominated by clay or heavy clay soils. National monitoring and estimations have shown that agricultural areas dominated by such clay soils have among the highest phosphorus losses. It has also been shown that a large proportion of P is transported in particulate form; hence, it is expected that sedimentation is the predominant P retention process in the selected wetlands. Sedimentation of clay may, however, be difficult to achieve in wetlands, and the aim of the study is to quantify the function of wetlands as sinks for the P lost from the catchments. Sedimentation and accumulation of particles are measured once a year using sedimentation plates (40×40 cm) placed on the bottom of the wetlands. Additional sedimentation traps (estimating gross sedimentation) have been placed in three of the wetlands, and those are emptied two times per year. This paper presents results for P and soil retention after the first year (in kg P ha-1 year-1), estimated by extrapolating the amount of sediment accumulated on the plates, and the content of total phosphorus (TP), to the whole wetland area. Furthermore, one wetland was selected for a detailed investigation of the effect of a vegetation filter, which in a previous study has been shown to have a positive effect on particle retention. Here, estimates of net and gross sedimentation are measured before, within and after the vegetation filter. To identify some factors of significant importance for wetland P load and retention efficiency, the statistical relationship with different wetland and catchment characteristics is analyzed. The factors included are the ratio wetland area to catchment area, average hydraulic load, and various catchment characteristics, e.g. soil type, topography, fertilization history, and soil P fractions. Since there is some uncertainty regarding sedimentation of fine clay particles (< 0.2 m), the size fractions of the accumulated sediment is determined to see whether or not the finest clay particles from the catchments settle in the wetlands. Previous studies have shown a correlation between particle size and bioavailability, where finer clay particles contain larger proportion of easily available P. Trapping the finest clay particles is therefore of particular ecological importance and needs to be further investigated.

  • 5.
    Johannesson, Karin M.
    et al.
    Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Kynkäänniemi, Pia
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ulén, Barbro
    Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Weisner, Stefan
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Tonderski, Karin S.
    Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Phosphorus and particle retention in constructed wetlands—A catchment comparison2015Ingår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 80, s. 20-31Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract 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 × 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. © 2014 Elsevier B.V.

  • 6.
    Johannesson, Karin M.
    et al.
    IFM Biology, Linköping University, Linköping, Sweden.
    Tonderski, Karin S.
    IFM Biology, Linköping University, Linköping, Sweden.
    Ehde, Per Magnus
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Weisner, Stefan E. B.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Temporal phosphorus dynamics affecting retention estimates in agricultural constructed wetlands2017Ingår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 103, nr Part B, s. 436-445Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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. © 2015 Elsevier B.V.

  • 7.
    Johannesson, Karin
    et al.
    Institutionen för fysik, kemi och biologi, Ekologi, Linköpings universitet, Linköping, Sverige.
    Tonderski, Karin
    Institutionen för fysik, kemi och biologi, Ekologi, Linköpings universitet, Linköping, Sverige.
    Wedding, Bengt
    Ekologgruppen i Landskrona AB, Landskrona, Sverige.
    Ehde, Per Magnus
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Weisner, Stefan
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Phosphorus load variations and retention in non-point source wetlands in southern Sweden2011Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Data from seven constructed wetlands receiving runoff from agricultural catchments in the south of Sweden were investigated with respect to phosphorus (P) retention. The seven wetlands differed in size (0.22-2 ha), design, land use and catchment characteristics. The hydraulic load varied between 7 and 725 m yr-1, which reflect the different geographical and hydrological conditions. The overall aim of this study was to increase the understanding of how water flow and inflow P concentration varations affect the P retention in constructed wetlands receiving runoff from arable land. Water flow was measured continuously, and time or flow proportional water samples were taken. Grab samples were taken during high flow periods and also to supplement the automatic water sampling. P retention varied between wetlands, from 1 to 58 kg ha-1 yr-1, and was correlated to the P load (R2=0.9, p<0.05). P retention in the wetlands varied strongly between years, and negative retention was recorded for some years and wetlands. When investigating monthly retention for each wetland, release of P corresponded to either high flow or possible anoxic conditions during low-flow periods in summer or during winter when ice covered the wetlands. Analyses of grab samples revealed a relationship between TP concentration and water flow for most wetlands. In some wetlands, P was transported mainly as particulate P (PP), but in other wetlands, soluble P was the dominating form in both inflow and outflow. Incoming concentrations varied greatly between wetlands (1-2000 μg l-1) which reflected the different catchment characteristics, e.g. land use, soil type and topography.

  • 8.
    Weisner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Johannesson, Karin
    IFM Biology, Linköping University, Linköping, Sweden.
    Thiere, Geraldine
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Svengren, Henrik
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Ehde, Per Magnus
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Tonderski, Karin S.
    IFM Biology, Linköping University, Linköping, Sweden.
    National Large-Scale Wetland Creation in Agricultural Areas—Potential versus Realized Effects on Nutrient Transports2016Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 8, nr 11, artikel-id 544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 9.
    Weisner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Johannesson, Karin
    Linköpings universitet, Linköping, Sverige.
    Tonderski, Karin
    Linköpings universitet, Linköping, Sverige.
    Näringsavskiljning i anlagda våtmarker i jordbruket: Analys av mätresultat och effekter av landsbygdsprogrammet2015Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    I denna rapport sammanställs och analyseras tidigare mätningar av avskiljning av fosfor och kväve i anlagda våtmarker. Resultaten indikerar hur hög fosfor­ och kväveavskiljning som kan uppnås i anlagda våtmarker i jordbrukslandskap i Sverige. Resultaten har även använts för att ta fram nya modeller för beräkning av avskiljning av fosfor och kväve i våtmarker där mätningar inte gjorts. Slutligen har dessa modeller använts för att beräkna hur hög avskiljning som kommer att uppnås i våtmarker som beviljats stöd inom landsbygdsprogrammet åren 2007– 2013 och hur mycket transporten av kväve och fosfor till havet kommer att minskas genom att dessa våtmarker har anlagts.

    De nya mätresultaten visar att fosforavskiljning underskattats i tidigare mätningar och i modeller som använts i tidigare utvärderingar. I enskilda väl utformade och placerade våtmarker kan 100 kilo fosfor och 1 000 kilo kväve per hektar våtmarksyta och år avskiljas. De nya resultaten indikerar även att man i framtida program för anläggning av våtmarker i jordbrukslandskapet bör kunna uppnå en genomsnittlig fosfor­ och kväveavskiljning på 50 respektive 500 kilo per hektar våtmarksyta och år, förutsatt att näringsavskiljning kan prioriteras vid placering och utformning av våtmarker. Kostnaden för avskiljning uppskattas till cirka 100 kronor per kilo fosfor och cirka 10 kronor per kilo kväve för sådana våtmarker om 50 procent av kostna­ derna fördelas till andra ekosystemtjänster och biologisk mångfald.

    Modellberäkningar på ett urval av våtmarker inom landsbygdsprogrammet som skalats upp till de 5 261 hektar som beviljats stöd under 2007–2013 visar att transporten av fosfor och kväve till lokala vattendrag kommer att minskas med cirka 25 ton fosfor per år och cirka 200 ton kväve per år. Det innebär att minsk­ ningen av transporten till havet som åstadkoms genom dessa våtmarker blir cirka 18 ton fosfor per år och cirka 170 ton kväve per år, vilket motsvarar 1,9 respektive 0,5 procent av transporten till havet från jordbruksmark.

    Anläggningen av våtmarker inom landsbygdsprogrammet har således haft betydelse för att minska fosfor­ och kvävetransporter såväl till lokala vattendrag som till havet. En jämförelse av genomsnittlig avskiljning per hektar våtmarksyta mellan landsbygdsprogrammet och den avskiljning som uppnås i individuella våtmarker visar emellertid att effektiviteten skulle kunna höjas betydligt i framtiden genom en bättre placering och utformning av våtmarker i landskapet.

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