Constructed floating wetlands made of natural materials as habitats in eutrophicated coastal lagoons in the Southern Baltic Sea

Abstract Eutrophication remains an environmental challenge in lagoons along the Southern Baltic Sea. Floating islands planted with emergent macrophytes are option to remove nutrients from eutrophicated waters. Furthermore, floating wetlands offer other ecosystem services such as provision of habitats. Numerous scientific studies have been conducted; however most remain on laboratory scale. This research explores challenges associated installations coastal environments and focuses sustainability island design, habitat function well nutrient removal. Most wetland designs use polyethylene, polypropylene, polyurethane or polyvinyl alcohol foam ensure buoyancy. For this study artificial polymer free design was developed tested. The constructions Darss-Zingst-Bodden-Chain were native which potential act ‘biodiversity-supplements’ adjacent wetlands: Bolboschoenus maritimus , Carex acutiformis, Iris pseudacorus, Juncus effesus, Lythrum salicaria, Schoenoplectus lacustris, Typha latifolia . chosen survived fluctuating salinities. After three months above-ground biomass harvested analyzed for concentrations. Phosphorus concentrations highest L. salicaria nitrogen I. pseudacorus Video monitoring field observations applied order observe animals. Birds did not breeding grounds, but grey heron ( Ardea cinerea ) a common visitor foraging. Especially surprising large amount juvenile eels Anguilla anguilla ). A diverse root network below boosts only removal serves shelter refuge fish endangered eel.