Here in France there has been an issue with toxic algea on beaches mainly ..... Ok totally caused by fertilizer run off into the sea . The best solution seems to be to
compost the algea and use it as fertilizer
Sea weed has been used as a fertilizer in Ireland for thousands of years
David
Living in Anjou , France,
For the many not for the few
http://www.permies.com/t/80/31583/projects/Permie-Pennies-France#330873