Spot the Difference: Seaweed, Kelp and Phytoplankton

Around 70% of the Earth’s surface is covered by oceans. So much of the life in our oceans has yet to be discovered, who knows what marvels we may uncover in the coming decades.

We do know that the oceans are full of life, from the microscopic to the gargantuan, that the rest of the planet depends on for everything from food to the air we breathe.

One thing we know for sure: if it weren’t for the life in our oceans, humans could not survive on Earth.

In this post, we’re going to focus in on three key forms of algae that humans take from the oceanic world to provide them with what they need to live healthier lives: seaweed, kelp and marine phytoplankton.


Did you know those slimy seaweed stalks that give you the creeps when they brush the bottom of your feet when you swim in the ocean can actually provide you with nutrients?

Seaweed, which is a type of algae, has a lot to offer. In many parts of Asia, seaweed is a very common snack. Here in North America, seaweed, Nori, in particular, is most often found wrapped around a piece of sushi. Based on its nutritional value, though, it might be time for all of us to start snacking on seaweed more often.

Reader’s Digest Best Health tells us that, even as dark green vegetables go, seaweed is incredibly nutrient dense. However, there are more types of seaweed than just the green kind you typically picture. Seaweed may be green, brown, red or blue-green.

Seaweed is the generalized name for a number of different oceanic plants and algae. There are numerous types and subgroups of algae that fall into this category. 

Seaweed, in general, has high amounts of calcium, vitamin B12, proteins and soluble fiber. Seaweed is also rich in DHA and EPA omega-3s fatty acids and antioxidants according to Wellness Mama.

The Guardian notes that a study in the British Journal of Nutrition, found arame and wakame, two popular types of seaweed, to be great sources of calcium, iodine, folate and magnesium. Purple laver, another type of seaweed, is especially rich in B vitamins.

According to Huffpost, “Seaweed’s best-known benefit is that it is an extraordinary source of a nutrient missing in almost every other food: iodine. Consuming healthy levels of iodine is critically important to maintaining a healthy thyroid, a gland in your neck which helps produce and regulate hormones.”

There are some subcategories of seaweed that are more common that others. Kelp is one such popular seaweed subgroup.


Often confused with seaweed more generally, kelp is an important subcategory.

Part of the brown algae group, kelp is often found in shallow ocean waters, in densely grown pockets that are almost forest-like. Kelp is the seaweed you see at the beach most often.

In comparison to other seaweeds, SFGate says kelp has more calcium but less protein per serving. In one cup of kelp, you’ll get 13% of your daily calcium intake.

Kelp is also a superior source of vitamin K when compared to other seaweed types.

According to SFGate, vitamin K’s main function in your body involves blood clotting — it activates proteins needed to set off a series of chemical reactions, called a coagulation cascade, that result in the formation of a blood clot. It also aids in cartilage and bone development. Kelp boasts a vitamin K content of 53 micrograms per cup, while Irish moss, laver and wakame each contain less than 5 micrograms per serving. Just 1 cup of kelp provides 42 percent of the daily intake for men and 59 percent for women.”

Like other types of seaweed, kelp is also a rich natural source of iodine.

Livestrong tells us that kelp is also rich in a number of vitamins, like vitamins C, B and E. Vitamin B is important for “cellular metabolism and providing your body with energy.” Vitamins C and E “are both strong antioxidants and promote blood vessel health.”

Dangers of eating seaweed and kelp

While getting your fill of seaweed and kelp will definitely benefit your health, there are some concerns. There definitely can be truth to the saying “too much of a good thing.”

While consuming enough iodine  is important for your health, too much of it can actually be detrimental. Since these foods have a lot of iodine in them, it’s worth noting.

Livestrong says that in terms of iodine consumption, “ingesting too much of it can negatively affect thyroid function, causing hypo- or hyper-thyroidism. Many thyroid specialists suggest that adults consume about 150 micrograms of iodine daily, although that is well below the level that could cause side effects. Table salt is iodized, so you should balance your kelp consumption against your salt intake.”

Adding kelp and seaweed into your diet is a good thing. Just be sure to monitor how much you’re taking in on a regular basis. If you like to eat a lot of these foods, switch to sea salt from table salt to reduce your overall iodine intake.

So how do seaweed and kelp differ from phytoplankton?

Marine phytoplankton

Marine phytoplankton is the basis of the aquatic food chain, feeding many forms of ocean life, from jellyfish to blue whales. Not only is marine phytoplankton full of nutrients for marine life, it’s also extremely nutritious for humans.

Like seaweed and kelp, marine phytoplankton is also an algae, but it’s different in some important ways.

For starters, marine phytoplankton is a single-celled aquatic microorganism or microalgae, which is invisible to the naked eye. 

Some of the nutrition found in seaweed and kelp is also found in marine phytoplankton, however, in most foods (including seaweed and kelp) those nutrients have to go through the standard process of digestion before they can be absorbed. This means that your body can’t absorb and use as much of them.

Because of its incredibly small size, marine phytoplankton is easily absorbed by the body. It can benefit your health in a number of ways due to the unique combination of nutrients within and their high level of bioavailability.

The bioavailable nutrients found within marine phytoplankton include trace minerals, chlorophyll, amino acids, DHA, EPA, antioxidants and a number of important vitamins and minerals, just to name a few.

This combination of nutrients can help your natural detox system, support your heart, feed your brain, give you energy, strengthen your immune system and more. To learn more about the benefits of phytoplankton, check out our recent post.

Marine phytoplankton is a true superfood, as it works hard for your health, providing a wide variety of benefits and a large quantity of nutrition in a very small number of calories. Its nutrient density simply can’t be matched.

Plus, while the seaweed and kelp that we eat is often harvested right out of the ocean, the marine phytoplankton in our Oceans Alive is grown in a controlled environment  called a photobioreactor. This ensures a consistent end-product that is as potent as possible, as well as free of environmental contaminants.

This makes Oceans Alive a safe and healthy superfood to eat every day, not just as an occasional addition to your salad or wrapped around your sushi.

Algae Advantage

Who knew ocean algae could be so good for you and come in so many different shapes and sizes?

Seaweed, kelp and marine phytoplankton all do a number of terrific things for your body. Make sure, for all three, you’re buying products that are top of the line in order to make sure you’re putting the healthiest versions of each product into your body.

Do your research on brands and don’t skimp on your health. For marine phytoplankton, Oceans Alive is the best option out there.

For a detailed product comparison and to learn more about what to look for when choosing your marine phytoplankton supplement, check out our recent post and video Phytoplankton Supplements Compared.  

Oceans Alive is an excellent way to boost your health daily, with almost zero calories. Discover more, now!

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