Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea
Eutrophication has been an issue of the Baltic Sea for a long time, causing de-creased water clarity due to enhanced growth of algae and oxygen depletion dur-ing the decomposition of algae. The study investigated the free water surface wetland Vilhelmsberg that treats agricultural runoff before the...
| Autor principal: | |
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2021
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| Acceso en línea: | https://stud.epsilon.slu.se/17209/ |
| _version_ | 1855572863994560512 |
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| author | Watschka, Manuela |
| author_browse | Watschka, Manuela |
| author_facet | Watschka, Manuela |
| author_sort | Watschka, Manuela |
| collection | Epsilon Archive for Student Projects |
| description | Eutrophication has been an issue of the Baltic Sea for a long time, causing de-creased water clarity due to enhanced growth of algae and oxygen depletion dur-ing the decomposition of algae. The study investigated the free water surface wetland Vilhelmsberg that treats agricultural runoff before the water reaches the Baltic Sea. The area of the wetland Vilhelmsberg (1.6 ha) corresponds to 0.1 % of its catchment area, in which the natural waterbody Maren is located upstream of the wetland. The main objectives of this study were to quantify the phospho-rus (P) accumulation, evaluate the possibility of recycling the sediment and as-sess the risk of internal loading. Therefore, sediment cores were collected in both waterbodies and analysed for (i) total P and P fractions, (ii) metal content, (iii) plant available P and (iv) particle size distribution. Results showed that the wetland Vilhelmsberg had a low sediment accumulation rate of 0.5 cm yr 1 and a low P accumulation of 13 kg ha 1 yr 1. The maximum potential P release rate of the wetland Vilhelmsberg (6.5 mg m 2 d-1) and Maren (5.2 mg m-2 d-1) indicated a small risk of internal loading. However, the proportion of clay particles at the wetland’s inlet was eight times higher than at the outlet, indicating resuspension probably caused by the inflowing Sea water. Thus, it is recommended to change the outlet design to improve the functioning of the wetland. Results also showed that it will be possible to return the sediments of the wetland Vilhelmsberg to the agricultural fields since the metal content was below Swedish legislation limits, whereas the sediment from Maren had too high nickel contents. The sediment represented a good soil amendment regarding the plant available P which was much higher in the wetland (10.5 mg per 100 g DS) and Maren (12.7 mg per 100 g DS), compared to the catchment soil (3.8 mg per 100 g DS). Concluding, the wetland Vilhelmsberg functions as a P trap by decreasing the P load from agricultural land to the Baltic Sea, but it had low particle and P accumulation which could be improved by design changes. |
| format | Second cycle, A2E |
| id | RepoSLU17209 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2021 |
| publishDateSort | 2021 |
| record_format | eprints |
| spelling | RepoSLU172092021-09-21T01:03:53Z https://stud.epsilon.slu.se/17209/ Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea Watschka, Manuela Water resources and management Eutrophication has been an issue of the Baltic Sea for a long time, causing de-creased water clarity due to enhanced growth of algae and oxygen depletion dur-ing the decomposition of algae. The study investigated the free water surface wetland Vilhelmsberg that treats agricultural runoff before the water reaches the Baltic Sea. The area of the wetland Vilhelmsberg (1.6 ha) corresponds to 0.1 % of its catchment area, in which the natural waterbody Maren is located upstream of the wetland. The main objectives of this study were to quantify the phospho-rus (P) accumulation, evaluate the possibility of recycling the sediment and as-sess the risk of internal loading. Therefore, sediment cores were collected in both waterbodies and analysed for (i) total P and P fractions, (ii) metal content, (iii) plant available P and (iv) particle size distribution. Results showed that the wetland Vilhelmsberg had a low sediment accumulation rate of 0.5 cm yr 1 and a low P accumulation of 13 kg ha 1 yr 1. The maximum potential P release rate of the wetland Vilhelmsberg (6.5 mg m 2 d-1) and Maren (5.2 mg m-2 d-1) indicated a small risk of internal loading. However, the proportion of clay particles at the wetland’s inlet was eight times higher than at the outlet, indicating resuspension probably caused by the inflowing Sea water. Thus, it is recommended to change the outlet design to improve the functioning of the wetland. Results also showed that it will be possible to return the sediments of the wetland Vilhelmsberg to the agricultural fields since the metal content was below Swedish legislation limits, whereas the sediment from Maren had too high nickel contents. The sediment represented a good soil amendment regarding the plant available P which was much higher in the wetland (10.5 mg per 100 g DS) and Maren (12.7 mg per 100 g DS), compared to the catchment soil (3.8 mg per 100 g DS). Concluding, the wetland Vilhelmsberg functions as a P trap by decreasing the P load from agricultural land to the Baltic Sea, but it had low particle and P accumulation which could be improved by design changes. Övergödning har länge varit ett problem för Östersjön som orsakat minskat vatt-nets siktdjup på grund av ökad algtillväxt och syrebrist till följd av nedbrytning-en av alger. Den här studien undersökte en anlagda våtmark vid Vilhelmsberg som renar vatten från jordbruksmark innan det mynnar i Östersjön. Våtmarks-ytan (1,6 ha) motsvarar 0,1 % av avrinningsområdet, inom vilken den naturliga vattenytan Maren ligger några hundra meter uppströms våtmarken. Syftet med studien var att kvantifiera fosforackumulationen, utvärdera möjligheten att åter-använda sedimentet och uppskatta risken för internbelastning av fosfor. Därför togs sedimentproppar i både våtmarken och Maren som analyserades med avse-ende på (i) totalfosfor och fosforfraktioner, (ii) metaller (iii) växttillgänglig fos-for och (iv) partikelstorleksfördelning. Resultaten visade både låg sediment ack-umulationshastighet 0,5 cm per år och låg fosforackumulation 13 kg per ha våt-marksyta och år i Vilmhelmsberg våtmark. Den maximala potentiella fosforfri-görelsehastigheten i Vilmhelmsbergs våtmark (6,5 mg m 2 d-1) och Maren (5,2 mg m-2 d-1) indikerade låg risk för internbelastning av fosfor. Däremot, var proportionen lerpartiklar vid våtmarkens inlopp åtta gånger högre än vid utlop-pet, vilket indikerar resuspension förmodligen orsakat av inflödande vatten från Östersjön. Det är därmed rekommenderat att ändra utformningen av utloppet för att förbättra våtmarkens funktion. Resultaten visar också att det är möjligt att återföra sedimentet från Vilmhelmsberg våtmark till åkermarken, då metallhal-terna låg under de svenska gränsvärdena. Däremot var nickelhalten för hög i Ma-rens sediment. Sedimentet representerar ett bra jordförbättringsmedel med avse-ende på växttillgänglig fosfor som var mycket högre i våtmarken (10,5 mg per 100 g) och Maren (12,7 mg per 100 g), jämfört med medelvärdet i uppströms jordbruksmark (3,8 mg per 100 g). Sammanfattningsvis fungerade Vilhelmsberg våtmark som en fosforfälla genom att minska belastningen från jordbruksmark till Östersjön, men den hade låg partikel- och fosforretention som skulle kunna öka genom ändrad utformning. 2021-09-06 Second cycle, A2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/17209/3/Watschka_M_210920.pdf Watschka, Manuela, 2021. Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea. Second cycle, A2E. Uppsala: (NL, NJ) > Dept. of Aquatic Sciences and Assessment <https://stud.epsilon.slu.se/view/divisions/OID-280.html> urn:nbn:se:slu:epsilon-s-17209 eng |
| spellingShingle | Water resources and management Watschka, Manuela Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title | Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title_full | Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title_fullStr | Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title_full_unstemmed | Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title_short | Phosphorus accumulation in a free water surface wetland discharging into the Baltic Sea |
| title_sort | phosphorus accumulation in a free water surface wetland discharging into the baltic sea |
| topic | Water resources and management |
| url | https://stud.epsilon.slu.se/17209/ https://stud.epsilon.slu.se/17209/ |