Transplantation of seagrass (Zostera noltei) as a potential nature-based solution for the restoration of historically contaminated mudflats.

Within the UN Decade on Ecosystem Restoration (2021-2030) framework, a Nature-based Solution (NbS) using Zostera noltei transplants was tested to restore a historically contaminated intertidal area. In-situ transplantation relied on patches of seagrass and sediment from a Donor meadow and its evolution was monitored for two years. The evaluation of the transplant success encompassed the seagrass coverage area, seagrass biomass, tissue mercury (Hg) accumulation, and photosynthetic efficiency. The transplant was successful, with gradual increases in the coverage area in the target area indicating adaptation to local conditions already after the first year. Although some significant differences were observed in biomass and tissue Hg concentration over time, the similar translocation factors suggest the plant has effective defensive mechanisms to prevent accumulation and cellular damage. Additionally, the normal seasonal pattern of photosynthetic parameters indicates that contamination is not impeding its photosynthetic performance and growth, suggesting this NbS as a viable restoration strategy.