Elodea

The invasive waterweed (Elodea spp.) is currently spreading extensively in Bremen’s Werdersee, limiting recreational activities and causing significant costs for public authorities. The aim of our project is to develop foundational concepts for the value-added use of Elodea biomass in Bremen and its surrounding areas.

In 2025, Elodea spp. spread massively in the Werdersee, leading to serious restrictions on leisure and sports activities as well as rising costs for public management. Similar situations have been reported in other German water bodies (e.g., Ruhr lakes, Lake Goitzsche). A permanent removal of Elodea from ecosystems where it is already established is currently not feasible due to technical and ecological constraints. Mechanical harvesting using mowing boats is presently the only practical control method, but it is costly and does not generate additional value. The harvested biomass is mostly composted.

The goal of this project is to develop conceptual foundations for a value-adding utilization of Elodea biomass in Bremen and nearby regions. This includes assessing the distribution and harvestable quantities of the plant, as well as analyzing its chemical composition and potential contamination. Since innovative utilization strategies could help offset the costs of removal, different valorization pathways will be identified and evaluated in terms of technical feasibility and economic viability.

The results of this project aim to provide a basis for the sustainable and economically viable use of invasive aquatic plants.