When we think of plants we generally imagine those plants growing in our gardens and the countryside around us. We wouldn’t normally think about the truly incredible plants growing in our oceans because we don’t get to appreciate them on a daily basis. Maybe you have been snorkeling, diving or been able to visit a marine center where you have been able to see these aquatic plants in their natural environment or maybe, like me, your usual encounter with marine plants is admiring the seaweed that is washed up on the beach. I encourage you to take some time and come on a learning journey with me, exploring the world of the marine plants.
Plants are classified into the kingdom PLANTAE, they are eukaryotic organisms and are distinguished by their ability to make their own food through photosynthesis. As we will discover most marine plants are just a little different from the land plants that we are most familiar with.
So, what are the main groups of marine plants?
Sea-grass is the only marine plant that can be classified as a true plant. While Seaweed, Kelp and Phytoplankton all create oxygen by photosynthesis they lack some of the distinctions that we would use to describe a true plant, they are classified as algae.
See the table below to compare Sea-grass to Seaweed:
| Sea-grass | Seaweed/Algae |
| Has a roots system. | No roots, has Holdfasts instead. |
| Photosynthesis occurs in the cells of the leaves. | Photosynthesis occurs in all the cells. |
| Produces flowers and seeds. | Produces spores. Do not flower or produce seed. |
| Has a vein system to carry food throughout the plant. | Does not have a vein system to carry food throughout the plant. |
| Parts of the plant include leaves, roots, rhizomes, shoots, flowers and seed. | Parts of the plant include blades, holdfasts and stipe. |
Kelp is a kind of brown algae, quite often though, you will see it labled as its own group among marine plant listings.
Phytoplankton are also classed as algae, they are the microscopic algae of the ocean. They can be broken into two groups, the Dinoflagellates and Diatoms.
Here are some ways that you can investigate the amazing world of aquatic plants with your children:
Watch this video ‘Plants of the Sea‘ by Gardening Australia.
Observe and compare seaweed with Nature Inspired Learning.
Make a Kelp Forrest Ocean Craft with The Art Kit.
Make dried seaweed art with Discover Wildlife.
Learn to forage and dry seaweed to eat in Australia with Milkwood.
Look at these sites to find activities, worksheets, or notebook pages:
- Compare Algae and Plants, downloadable resources. At Learn For Your Life.
- What I Know about the Ocean Notebook Page.
- Ocean Plants colouring page.
- Plants vs Algae live worksheet.
- Energy from Algae worksheet.
- Create a venn diagram comparing marine plants. Or download this worksheet.
If you are looking for some math activities related to marine plants why not try these ideas.
- Cooking includes measuring and time skills, so take your math into the kitchen and make some sushi . You can find a recipe for Seaweed Chips here. For 11 different recipes that are not sushi look HERE.
- Collect some seaweed. Measure and weight each sample. Write down your findings. Dry and press your samples, measure and weigh again. What do you notice? What do you wonder?
Your teens might like to do a research project on Marine Aquatic Plants. You can download a project pack here to help them put it together.
Some book recommendations? Of course!
