Ocean Harvests: Eco-Friendly Benefits of Seaweed

Aug 29, 2025 08:26AM ● By Maya Whitman

kerriekerr from Getty Images Signature/CanvaPro

Some may associate seaweed with giant kelp forests or savory sushi wraps, but these species of multicellular marine algae have become key players in the food, cosmetic and industrial arenas. Seaweed farming around the world, including more recently in the United States, shows promise as a natural solution to climate change, ocean acidification and the plastics crisis. Such crops provide not only nutritious food for humans and animals but also chemical-free fertilizers for backyard gardens and agriculture.

“When managed and cultivated ethically in cooperation with the natural laws, just like land farms, seaweed farms can be little vibrant plots of biodiversity and primary productivity, supporting all the powers of nature for good,” says Sarah Redmond, founder of Springtide Seaweed, in Gouldsboro, Maine, the largest organic seaweed company in the United States.

Environmental Hero

There are thousands of species of seaweed, and they thrive in areas where other marine life is failing due to ocean acidification. Their presence is a boon for the environment because they release nutrients into the ocean, while also sequestering carbon from the atmosphere, thereby reducing the effects of climate change.

As Redmond explains, “Ocean acidification is the lowering of overall pH in the oceans, which can impact all marine life, especially shell-forming organisms. Growing seaweed can help reduce the impacts of acidification locally, during the day, when the plants are taking in carbon for photosynthesis. Some of the carbon is remineralized back into inorganic forms, some is consumed as food, some is lost as dissolved or particulate organic carbon, and some is buried in sediments at sea. All of the algae—micro and macro seaweeds—drive the ocean’s carbon cycle.”

Seaweed is introduced in aquaculture because of its ability to boost water quality and convert fish waste into usable nutrients. According to Charles Yarish, professor emeritus of marine ecology at the University of Connecticut and chief scientist with GreenWave, a global nonprofit network of regenerative ocean farmers, “Seaweed farming in the United States is principally kelp farming, and we have nutrient-rich waters. Seaweeds can reduce carbon dioxide and nitrogen as they photosynthesize during daylight hours and take it into their biomass.”

Yarish highlights the cutting-edge efforts of Macro Oceans, in West Sacramento, California, which seeks to help the world transition away from petroleum-based products by developing eco-friendly biomaterials from seaweed for use in cosmetics, food and other industries.

Nutritional Dynamo

“Seaweeds are very nutritious, with minerals, protein and vitamin C,” says Yarish. Rich in iodine, it has been a diet staple for coastal cultures since prehistoric times, and more than 145 varieties are consumed worldwide today. Across the United States, there are dozens of farms in New England, Alaska and the Pacific Northwest that specialize in the cultivation of bull kelp, dulse, ribbon kelp and sugar kelp used in sauces, salads, seasonings and Asian cuisine.

According to Redmond, “By replacing table salt with the natural, organic mineral salts from seaweeds, we can rebalance our sodium and potassium levels and add essential micronutrients to our diets.”

Common edible seaweeds like wakame, kelp, kombu, nori and dulse are tasty additions to soups and salads that can foster good thyroid health. According to 2018 findings published in the Iranian Journal of Basic Medical Sciences, extract of the seaweed variety Sargassum oligocystum offers anti-diabetic effects in rats and is worthy of further research. Japanese research published in 2021 in the Journal of Atherosclerosis and Thrombosis suggests that seaweed consumption might be valuable in preventing strokes in men.

Conscious Packaging

According to CleanHub, an organization dedicated to preventing plastic pollution in our oceans, it is estimated that 95 percent of all beauty industry packaging is thrown away every year. Companies like UK-based Notpla and Kelpi, as well as California-based Sway, are using biodegradable seaweed bioplastics to make a difference. Similarly, the restaurant and food industries are developing options to replace single-use plastics like containers and wraps with marine-based packages. Currently, seaweed packaging is more costly, but experts predict lower prices as technology advances.

Maya Whitman is a frequent writer for Natural Awakenings.