Bladderwrack, is a variety of kelp or seaweed that is harvested along the North Atlantic coastline. In addition to a high degree of mucilage and cellulose, bladderwrack is a rich source of sodium, potassium and iodine. The dried kelp, although a bit salty-tasting, is sometimes used in teas and in other beverages. Powdered bladderwrack is added to foods as a natural source of iodine but with less sodium than table salt. Bladderwrack powder is also used as an organic fertilizer.