Seaweed Facts: Lesson for Kids

Instructor: Mary Beth Burns

Mary Beth has taught 1st, 4th and 5th grade and has a specialist degree in Educational Leadership. She is currently an assistant principal.

Have you heard about how amazing seaweed is? Come learn about the different types of seaweed, and the amazing things it is doing for the environment and human health!

What is Seaweed?

When we think of ocean life, our minds typically pictures sharks, fish or whales, but rarely do we immediately picture seaweed. However, seaweed is all over the ocean and has been for more than 600 million years. Categorized as a nonvascular plant, this means that seaweed does not have a system to transport food and water, so seaweed makes its own food from the energy it gets from the sun. This process is known as photosynthesis. This makes seaweed an algae, in addition to the fact that it doesn't have leaves, roots or stems.

Types of Seaweed

Phytoplankton under a microscope

Seaweed comes in all shapes, sizes and colors. The tiniest seaweed, known as phytoplankton, is microscopic, which means it cannot be seen with the human eye. Kelp, a type of brown seaweed, can be several feet long. Seaweed can be brown, green, red or black and make for a beautiful display of color in the ocean. Sometimes, seaweed will wash up on the shore. Seaweed normally feels like squishy, slimy goop, so don't be alarmed if you accidentally step on some! It might feel kind of yucky, but it's just harmless seaweed.

Seaweed in the Environment

Do you like being able to breathe? It is a pretty great thing, considering that is what keeps us alive. Well, you have to thank seaweed for a big part of that! Many scientists believe that algae is responsible for up to 87% of the world's oxygen. Remember how algae uses photosynthesis to use the sun to produce energy? This is how they make oxygen for us to breathe. Other plants on land also photosynthesize, but since the ocean makes up more that 70% of the Earth's surface, the algae is doing most of the heavy lifting.

Kelp assuming its role in the food chain

Seaweed is an important part of the ocean food chain. For example, the crab eats the seaweed, the squid eats the crab, the elephant seal eats the squid and the killer whale eats the elephant seal. Therefore, if seaweed did not exist, neither would any of the animals in the food chain. It is important to keep in mind that crab is only one of many sea creatures that eat seaweed, so many other animals would not exist if it weren't for seaweed.

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