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What is Kelp?

Niki Foster
Niki Foster
Niki Foster
Niki Foster

Kelp is a type of seaweed or algae belonging to the order Laminariales. Though its appearance is similar to that of plants, it is technically not a plant, but a protist. There are many different kinds, making up around 30 genera.

This seaweed grows in underwater forests, in shallow, clear waters cooler than 68°F (20°C), where it grows rapidly and offers food and protection for other marine life. Many people recognize kelp from a trip to the beach. It is anchored to the ocean floor by a structure known as a holdfast, and most of its body resembles a stem with leaves, correctly termed a stipes with blades. The seaweed also features air-filled bladders that allow the rest of the body to float and bring the leaf-like blades to the surface of the water.

Live kelp underwater.
Live kelp underwater.

Humans throughout history have found many uses for kelp. Soda ash, once produced by burning seaweed, is a primary ingredient in glass and soap. Alginate, a carbohydrate harvested from it, is used as a thickening agent in toothpaste, ice cream, jelly, and other products. Some species are also used in certain cuisines, particularly in Japan, or as an organic fertilizer.

Kelp is a very versatile ingredient in food. It can be used as a flavoring, a garnish, a vegetable, or a snack food. Dried sheets are often used to wrap sushi and other foods. It has a distinctive taste and is both decorative and flavorful.

Dried kelp.
Dried kelp.

Though soda ash can now be produced in a lab, kelp was once the world's major source of the material. Scottish Highlanders displaced from their traditional farmlands throughout the 18th and 19th centuries sometimes turned to harvesting the ash to make a living. Though the industry eventually collapsed, kelp remains a commonly used fertilizer in Scotland.

Frequently Asked Questions

What exactly is kelp, and where can it be found?

Soda ash, which can be made from kelp.
Soda ash, which can be made from kelp.

Kelp is a type of large brown seaweed that belongs to the order Laminariales and thrives in nutrient-rich, shallow saltwater near coastal fronts around the world. It forms dense underwater forests that are among the most productive and dynamic ecosystems on Earth, providing habitat for a wide variety of marine life.

How does kelp benefit the environment?

Soda ash produced in a lab has to some extent replaced the use of kelp.
Soda ash produced in a lab has to some extent replaced the use of kelp.

Kelp forests are ecological powerhouses, offering critical habitat and food for marine organisms. They act as natural carbon sinks, absorbing carbon dioxide from the atmosphere, which helps mitigate climate change. Moreover, kelp helps protect coastlines by diminishing the power of waves and preventing erosion.

Can kelp be used for human consumption?

Kelp is used to wrap sushi.
Kelp is used to wrap sushi.

Yes, kelp is edible and highly nutritious, rich in vitamins, minerals, and antioxidants. It's a staple in many Asian cuisines, commonly used in soups, salads, and as a wrap for sushi. Kelp is also a source of iodine, which is essential for thyroid function, and is increasingly popular as a health supplement.

What are the commercial uses of kelp?

Kelp has a variety of commercial applications beyond food. It's used in the production of alginate, a thickening agent found in ice cream and cosmetics. Kelp is also utilized in fertilizers and animal feed, and there's growing interest in its potential as a sustainable biofuel source.

How does kelp reproduction occur?

Kelp is a protist, not a plant.
Kelp is a protist, not a plant.

Kelp reproduces both sexually and asexually. In sexual reproduction, kelp releases spores that develop into male and female gametophytes, which then produce eggs and sperm. Fertilization occurs in the water, leading to the growth of new kelp sporophytes. Asexually, kelp can reproduce through fragmentation, where pieces break off and grow into new individuals.

Are kelp populations at risk, and what are the threats?

Kelp ecosystems are facing threats from climate change, pollution, and overharvesting. Rising ocean temperatures and acidification can disrupt their growth and reproductive cycles. Invasive species, like the purple sea urchin, can overgraze kelp forests, leading to their decline. Efforts in kelp forest conservation and sustainable management are crucial to protect these vital ecosystems.

Niki Foster
Niki Foster

In addition to her role as a AllThingsNature editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

Learn more...
Niki Foster
Niki Foster

In addition to her role as a AllThingsNature editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

Learn more...

Discussion Comments

turquoise

When I went scuba diving in Hawaii last summer, the sea floor was full of kelp. It looked so gorgeous!

I love how the light travels under water and reflects on the kelp. It's also cool how they sort of dance in the water. It's definitely worth seeing.

Aside from their cool appearance, I think kelp is also a food source for many fish and sea creatures right? Don't many fish feed off of them? I know they live in them, whenever I would touch kelp while diving, several fish would come out.

ysmina

@alisha-- Yes, sea kelp has iodine as do most ocean seaweeds.

I'm not sure about treating an iodine deficiency with it but I know that kelp is used extensively in Japan. When they had that earthquake and faced the threat of radiation, people there started eating kelp and taking kelp supplements to protect themselves. Apparently, kelp can help prevent the damage caused by radiation on the body and can help detoxify the body of it.

Why don't you ask your doctor about kelp? If he says it's okay, I think you should give it a try. Kelp is quite amazing from what I understand.

discographer

I just got back from my doctor's office and apparently I have an iodine deficiency. I was doing some reading about this and one source suggested taking sea kelp supplements. So I guess kelp is a natural source of iodine. How much iodine does it have exactly?

Has anyone here taken kelp supplements to treat an iodine deficiency?

My doctor told me to eat more salt, but I can only put so much salt in foods. If kelp supplements are an option, I think I would prefer that. Please share your experience!

jadona2006

can I take kelp supplements if allergic to iodine?

anon14405

Can one take kelp supplments saftely if they are allergic to shellfish?

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    • Live kelp underwater.
      By: Daniel Poloha
      Live kelp underwater.
    • Dried kelp.
      By: sahua d
      Dried kelp.
    • Soda ash, which can be made from kelp.
      By: Aaron Amat
      Soda ash, which can be made from kelp.
    • Soda ash produced in a lab has to some extent replaced the use of kelp.
      By: WavebreakMediaMicro
      Soda ash produced in a lab has to some extent replaced the use of kelp.
    • Kelp is used to wrap sushi.
      By: nalineimages
      Kelp is used to wrap sushi.
    • Kelp is a protist, not a plant.
      By: Juulijs
      Kelp is a protist, not a plant.