Kelp Vs. Seaweed

Resembling a tree growing in the ocean, kelp is a type of seaweed. Like other seaweeds, kelp has no roots, but rather a holdfast that keeps it anchored to the ocean floor. Unlike plant roots, the kelp's holdfasts do not take in nutrients. Kelp also have an air bladder on the end of each blade, or leaf, that help keep it and the stipe, or stem, afloat as the plant climbs toward the bright sunlight shining on the water's surface.

Types of Seaweed

True seaweeds, like kelp, are marine algae. Some plants that are called seaweeds are actually just submersed vegetation. Seaweeds grow in waters all over the globe, while kelp is unique to clear, shallow waters with temperatures below 68 degrees Farenheit. All seaweeds, of which there are about 10,000 known species, are categorized into three basic types, by color: brown, red and green. Kelp is the largest of the brown seaweeds. Other brown seaweeds that are not in the kelp family include Bottlebrush Seaweed, Seersucker, Rockweed, Sea Cauliflower, Sea Fungus, Sea Cabbage, Wireweed and Soda Straws.

Types of Kelp

Just as there are many kinds of seaweed, so are there many kinds of kelp. Vine Kelp or Giant Kelp is not only the largest of its kind, but with a stem that can extend up to 1,500 feet, is also the world's longest plant. Other types of kelp include Bull, Devil's, Fan, Flattened Acid, Green Acid, Perennial, Sugar, Split, Three-Ribbed and Winged Kelp. In all, there are about 300 known types of kelp, each type distinguished by its shape and growth habits.

Kelp vs. Bladderwrack

Sometimes what is sold as kelp is actually bladderwrack, a completely different kind of seaweed. It may also go by the name kelpware, sea kelp or Atlantic kelp. Bladderwrack is often a component in kelp supplements, also lending to the misnomer. As per FDA labeling guidelines, if bladderwrack is contained in a kelp product you purchase, it will say so on the label.

Uses

Not all kelp is edible. If you are planning to cook with kelp, be sure to purchase kelp labeled as edible. Before cooking with edible kelp you must first remove the olive-colored membrane surrounding it. Different seaweeds are made into different consumer products and ingredients. Burned kelp is made into soda ash while a kelp carbohydrate called alginate is used as a thickener in products like toothpaste and ice cream.

Nutritional Information

All seaweeds are rich in iodine and other nutrients, but each type of seaweed possesses these nutrients in different combinations and amounts. Kelp has one of the highest concentrations of iodine of any species of seaweed, with approximately 1,542 mcg per gram. Kelp granules, used as a salt substitute, contain 8,165 mcg of iodine per gram. Kelp is mostly water, containing 81.58 g water per 100 g. One-hundred grams of kelp also contains 43 calories, 1.68 g of protein, 0.56 g of fat, 9.57 g of carbohydrates, 1.3 g of dietary fiber, 0.6 g of sugars and is high in calcium, iron, sodium, magnesium, phosphorus and potassium. It also contains significant amounts of vitamins A, C, K, beta carotene folate, choline and trace amounts of all the amino acids.