What Are the Uses for Seaweeds?

Seaweed on wet beach sand

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Marine algae, commonly called seaweed, provides food and shelter for marine life. Algae also provide the bulk of the Earth's oxygen supply through photosynthesis.

But there is also a myriad of human uses for algae. We use algae for food, medicine, and even to combat climate change. Algae may even be used to produce fuel. Here are some common and sometimes surprising uses of marine algae.

Food: Seaweed Salad, Anyone?

Seaweed salad
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The most well-known use of algae is in food. It's obvious you're eating seaweed when you can see it wrapping your sushi roll or on your salad. But did you know that algae can be in desserts, dressings, sauces, and even baked goods?

If you pick up a piece of seaweed, it may feel rubbery. The food industry uses gelatinous substances in algae as thickeners and gelling agents. Look at the label on a food item. If you see references to carrageenan, alginates, or agar, then that item contains algae.

Vegetarians and vegans may be familiar with agar, which is a substitute for gelatin. It can also be used as a thickener for soups and puddings.

Beauty Products: Toothpaste, Masks, and Shampoos

Aesthetician peeling off a seaweed mask
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In addition to its gelling properties, seaweed is known for its moisturizing, anti-aging and anti-inflammatory properties. Seaweed can be found in facial masks, lotions, anti-aging serum, shampoos, and even toothpaste.

So, if you're looking for those "beachy waves" in your hair, try some seaweed shampoo.


Researchers review the results of a pilot study, which is an important step to assessing the feasibility of a larger research project.
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The agar found in red algae is used as a culture medium in microbiology research.

Algae is also used in a variety of other ways, and research continues on the benefits of algae for medicine. Some claims about algae include the ability of red algae to improve our immune system, treat respiratory ailments and skin problems, and cure cold sores. Algae also contain abundant amounts of iodine. Iodine is an element required by humans because it is necessary for proper thyroid functioning.

Both brown (e.g., kelp and Sargassum) and red algae are used in Chinese medicine. Uses include treatment for cancer and for treating goiters, testicular pain and swelling, edema, urinary infections, and sore throat.

Carrageenan from red algae is also thought to reduce transmission of human papillomavirus or HPV. This substance is used in lubricants, and researchers found that it prevents HPV virions to cells.

Combat Climate Change

Seaweed Farm
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When marine algae conduct photosynthesis, they take up carbon dioxide (CO2). CO2 is the main culprit cited in global warming and the cause of ocean acidification.

An MSNBC article reported that 2 tons of algae remove 1 ton of CO2. So, "farming" algae might lead to those algae absorbing CO2. The neat part is that those algae can be harvested and turned into biodiesel or ethanol.

In January 2009, a team of UK scientists discovered that melting icebergs in Antarctica release millions of iron particles, which are causing big algal blooms. These algal blooms absorb carbon. Controversial experiments have been proposed to fertilize the ocean with iron to help the ocean absorb more carbon.

MariFuels: Turning to the Sea for Fuel

Scientist examining algae
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Some scientists have turned to the sea for fuel. As mentioned above, there is the possibility to convert algae to biofuels. Scientists are researching ways to convert sea plants, particularly kelp, into fuel. These scientists would be harvesting wild kelp, which is a fast-growing species. Other reports indicate that about 35% of the U.S.'s need for liquid fuels could be provided each year by halophytes or saltwater-loving plants.

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Kennedy, Jennifer. "What Are the Uses for Seaweeds?" ThoughtCo, Apr. 5, 2023, thoughtco.com/human-uses-for-seaweeds-2291917. Kennedy, Jennifer. (2023, April 5). What Are the Uses for Seaweeds? Retrieved from https://www.thoughtco.com/human-uses-for-seaweeds-2291917 Kennedy, Jennifer. "What Are the Uses for Seaweeds?" ThoughtCo. https://www.thoughtco.com/human-uses-for-seaweeds-2291917 (accessed May 29, 2023).