Two of the South West’s leading marine organisations have joined forces to enhance seagrass restoration in the Plymouth Sound National Marine Park.
The Ocean Conservation Trust and the University of Plymouth have been carrying out experiments in the University’s COAST (Coastal, Ocean and Sediment Transport) Laboratory to look at how seagrass planting units are influenced by hydrodynamic forces.
The seagrass planting units are made from a cotton layer, with a hessian intertwined mat topped with sand. The experiments are assessing how the planting units cope with shear stress from waves and currents, and how resistant the hessian mats are to these different hydrodynamic conditions.
They have highlighted the physical limitations of the planting units and found the best formation to place the planting units on the seabed, so they protect each other and the seagrass seedlings within from waves and currents, allowing the seagrass to grow.
Armed with this new knowledge, the Ocean Conservation Trust’s Commercial Dive Team will be deploying the planting units in Plymouth Sound, using metal pegs to secure the units into the sediment.
This will form part of their work in restoring seagrass beds as part of the four-year LIFE Recreation ReMEDIES Project, which aims to plant a total of eight hectares of seagrass meadows – four hectares in Plymouth Sound and four hectares in the Solent Maritime Special Area of Conservation.