Kelp vs seaweed: What are the main differences between these oceanic plant species?

Seaweed and kelp both are marine algae species. Kelp belongs to the subspecies of seaweed. In other words, all kelp falls under the category of seaweed, but not all seaweed qualifies as kelp.

To truly grasp the distinctions in the kelp vs seaweed comparison, we must delve deeper into their habitats, sizes, colors, and uses.

8 Differences between Kelp vs Seaweed

DifferenceKelpSeaweed
1. ClassificationSpecific type of large brown algaeBroad term encompassing various species
2. ColorMainly brown or olive-greenVarious colors, including green, red, brown
3. Size & GrowthGenerally larger, up to 150 feetVaries in size from small to large
4. Habitat
– Water DepthPrefers deeper ocean environmentsOccupies shallow and deep areas
– Water SalinityExclusive to saltwater, found in cooler regionsCan thrive in both saltwater and freshwater
– Water TemperatureFound in both temperate and tropical watersThrives in various water temperature ranges
– DiversityPredominantly in areas with hard substratesInhabits diverse environments
5. Environmental RoleForms underwater forests, vital marine habitatsEfficient carbon storage, aids in climate change mitigation
6. UsesValuable in food, cosmetics, fertilizers, animal feed, industrial applications, and wastewater treatmentAlso used in similar applications, but less commonly in cosmetics and industrial uses
7. Health BenefitsRich source of iodine and calcium, supports thyroid health, strong bones, and teethOffers prebiotic fiber, boosts immune system, and provides antioxidants for health
8. Carbon StorageRapid growth efficiently absorbs and stores substantial carbonStores carbon but at a slightly lower scale and pace
Kelp vs Seaweed Comparison

1. Classification

Seaweed is a broad term that encompasses various marine algae, while kelp is a specific type of large brown algae.

Encompassing over 10,000 marine-based plant and algae species, including well-known brown seaweeds like Ascophyllum nodosum.

In contrast, sea kelp, while part of the seaweed family, represents the largest subgroup, noted for its substantial size and typically categorized as brown seaweed.

2. Color

Seaweed typically appears in a variety of colors, including green, red, and brown, whereas kelp is mainly brown or olive-green in color.

Seaweed appears in a diverse spectrum. Those nearer to the water’s surface often sport green hues, courtesy of chlorophyll, akin to sea lettuce. Yet, seaweed’s color palette doesn’t stop there; it can include shades of red and brown due to pigments like phycoerythrin, phycocyanin, fucoxanthin, and phlorotannin.

In contrast, sea kelp, a subgroup within the seaweed family, is primarily associated with brown shades. Their distinctive coloration arises from carotenoid pigments like fucoxanthin and phlorotannin. This brown hue signifies their adeptness at capturing optimal light for photosynthesis in deeper, dimly lit ocean environments.

3. Size & Growth Rate

Seaweed can vary significantly in size, from tiny microalgae to larger species. Kelp, on the other hand, is generally larger, often growing up to 150 feet in length.

Kelp tends to grow faster than many types of seaweed, which can be important for maintaining coastal biodiversity.

4. Habitat

The habitat of kelp and seaweed is a key factor that sets them apart in the underwater world. Both of these marine plants thrive in various aquatic environments, but their preferences and adaptations vary.

Water Depth

Both, kelp and seaweed are skilled at adapting to different water depths. While some species of seaweed prefer shallower areas closer to the water’s surface, others venture into deeper regions. This flexibility allows them to occupy a range of niches in the underwater ecosystem. Though, kelp tends to prefer deeper ocean waters.

Water Salinity

Seaweed can be found in both saltwater and freshwater environments, including rivers and lakes (but only if they are not among the most polluted rivers in the world). Kelp, however, is exclusive to saltwater and is commonly found in cooler coastal regions.

Water Temperature

The adaptability of kelp and seaweed extends to water temperature as well. These marine plants can be found in waters that vary in temperature. Some species thrive in cooler, temperate waters, while others flourish in warmer, tropical environments.

Diversity

Seaweed species inhabit diverse environments, from rocky shores to sandy bottoms. Kelp, however, predominantly thrives in so-called kelp forests, in areas with hard substrates, like rocky coastlines.

5. Environmental Role

Kelp and seaweed, while both marine vegetation, differentiate themselves in their environmental roles.

Kelp forms intricate underwater forests, acting as vital habitats for a diverse array of marine creatures, akin to terrestrial forests on land. These kelp forests display remarkable productivity, resembling rainforests, as they purify water, cycle nutrients, and help safeguard coastlines.

On the other hand, seaweed, a master of carbon storage, efficiently captures atmospheric carbon, aiding in the fight against climate change. The distinct roles of kelp and seaweed emphasize their respective significance in marine ecosystems and environmental preservation.

6. Uses

Food & Nutrient Content

Both kelp and seaweed are nutrition powerhouses, commonly featured in global cuisine. They offer iodine for thyroid health, high calcium for strong bones, and antioxidants to combat cancer.

The only problem: Seaweed products, such as seaweed gelatin (more commonly known as agar agar) are more expensive compared to their traditional alteratives. The reasons why sustainable product are more expensive is because no chemicals are used during the production process and wages are higher. Plus: There is a high demand and little supply. Unfortunately organic seaweed is no exception here.

Cosmetics

Seaweed extracts are popular in skincare products due to their hydrating and antioxidant properties, promoting skin health. However, kelp not so much.

For those looking to make their entire dental routine more eco-friendly, you can explore 7 Ways to Make Your Dental Routine More Eco-Friendly, for tips on sustainable oral care practices.

Fertilizers

Processed into plant fertilizers, seaweed and kelp enhance soil with vital nutrients, providing an eco-friendly alternative to chemical fertilizers.

Animal Feed

Both of these marine plants contribute essential nutrients to animal feed, supporting livestock growth and aquaculture health.

Industrial Uses

Both kelp and seaweed, but especially kelp is used in several industrial applications, such as in manufacturing paints, adhesives, and textiles. Seaweed is often used in foods like sushi and snacks, while kelp is a source of alginates used in various industries, including pharmaceuticals and cosmetics.

Wastewater Treatment

Seaweed, but particularly kelp, aids in detoxifying contaminated water sources by absorbing heavy metals, contributing to cleaner water and a healthier ecosystem.

7. Health Benefits

Kelp offers a rich source of iodine critical for thyroid health and regulation of hormones. Additionally, its higher calcium content promotes strong bones and teeth.

In contrast, seaweed contributes prebiotic fiber to support gut health and strengthen the immune system.

Moreover, both kelp and seaweed deliver valuable antioxidants, combating free radicals that could potentially lead to cancer and age-related issues.

8. Carbon Storage

Kelp and seaweed demonstrate distinct strengths in carbon storage.

While both play vital roles, kelp stands out with its rapid growth, efficiently absorbing substantial amounts of carbon and storing it underwater. This exceptional capability contributes significantly to climate change mitigation efforts.

On the other hand, seaweed, with its diverse range of species, also stores carbon but at a slightly lower scale and pace.

The distinctions between kelp and seaweed in terms of carbon storage highlight their individual roles in preserving our planet’s environmental balance. In the kelp vs. seaweed comparison, both reveal their combined importance as a nature-based solution to climate change.

kelp vs seaweed

FAQs

What’s the difference between seaweed and kelp?

Seaweed is a broad term encompassing various marine algae, while kelp is a specific subgroup of seaweed known for its size and habitat.

What does seaweed include?

Seaweed includes a vast array of marine macroalgae, comprising over 10,000 species that draw nutrients from water rather than soil.

Are kelp and seaweed the same thing?

No, kelp and seaweed are not identical. While kelp falls under the seaweed category, they have distinct characteristics, including habitat, size, and color.

Can you eat seaweed and kelp?

Yes, both seaweed and kelp are edible and feature prominently in global cuisines, particularly in Japanese and Chinese dishes.

Is kelp or seaweed better for you?

Kelp, with its unique attributes and nutritional profile, offers certain advantages, such as iodine content essential for thyroid health.

What type of seaweed is kelp?

Kelp belongs to the brown seaweed category, characterized by its brown coloration.

Can I use dried seaweed instead of kelp?

Dried seaweed can serve as a substitute for kelp in various culinary applications, providing a similar marine essence.

Is seaweed meal the same as kelp powder?

Seaweed meal and kelp powder have slight variations in composition, with kelp powder typically being derived from brown seaweed.

Is kelp or seaweed used in sushi?

Red seaweed, often referred to as nori, is typically used to wrap sushi rolls. It’s a specific type of seaweed distinct from kelp.

Does kelp taste like seaweed?

Yes, kelp maintains the characteristic taste of seaweed, encompassing a savory, marine flavor profile. These answers shed light on the nuances of kelp and seaweed, helping you navigate their distinctions and culinary applications.

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Olivia Williams

Olivia is one of the most celebrated authors at EcoCation, renowned for her extensive contributions in the fields of biology and botany. With over 500 published articles, she has established herself as a leading voice in the scientific community, captivating readers with her insightful and informative content. Olivia’s deep understanding of the natural world, combined with her engaging writing style, makes complex biological and botanical concepts accessible to a wide audience. Her dedication to educating and inspiring others about the wonders of nature has made her a pivotal figure at EcoCation, fostering a greater appreciation for the environment.