Dried seaweed was the first source of iodine and alkalies needed to
manufacture soap and glass, both of which were synthesized from the
compounds sodium and potassium.
Bladderwrack is so-named because the plant contains tiny sacs that
resemble bladders. As with other species of brown algae, the cell walls
of the plant contain a high degree of alginic acid. Also known as algin,
this polysaccharide bonds to water molecules to form a gelatinous
material that is used in the food, cosmetic and textile industries.
Historically used in the British Isles as an alternative for manure and
artificial fertilizer for broccoli and potato crops, dried bladderwrack was
sprinkled on the ground or burnt and the ash used in the same
way.
