UK seagrass meadows deliver multiple goods and services and have the potential to contribute significantly to addressing the impacts of the climate and biodiversity crises (Unsworth et al., 2018; Macreadie et al., 2021). However, estimates suggest that between 25% and 80% of UK seagrass has been lost since the 1930s with minimal signs of recovery (Green et al., 2021). Eutrophication, driven by increased nutrient inputs, presents the biggest threat to seagrass meadows (Jones & Unsworth, 2016). Whilst being at the forefront of the impacts of eutrophication, seagrasses can also be used as reliable indicators of coastal environmental conditions.
This report forms part of the first UK-wide study of nutrient content in the seagrass species Zostera noltii. Eight samples were collected across the East Coast of England and analysed for elemental compositions of Carbon, Nitrogen and Phosphorous ratios and the stable isotopes of Carbon and Nitrogen. A global literature review was conducted to provide baseline figures to assess whether nutrient concentrations deviated. Results demonstrate that there is extreme nutrient enrichment across sites compared to the global averages. Only one site was in line with the global baseline: Jacques Bay in the Stour Estuary. The remaining sites will therefore likely be experiencing a breakdown in population structure and plant morphology deterioration due to algal overgrowth and a toxic environment.
This work will lead to an improved understanding of Z. noltii nutrient concentrations for future research to build upon. It will also be critical in informing seagrass restoration ambitions moving forward.