talking points for nature guides
Seaweeds in general | Division Chlorophyta | Division Cyanophyta | Division Phaeophyta | Division Rhodophyta
index to talking points for nature guides
For nature guides: introducing seaweeds
updated Aug 08

Don't step on the seaweeds!
A 'bloom' of seaweeds collected on the high shore make a good 'first station' to sensitise visitors to the fact that every inch of the shore is alive. Show them the tiny animals that live among the seaweeds so they avoid stepping on thick layers of seaweed.

It's also a good activity to do if the tide is too high to go out and you need to amuse the visitors on the high shore for a while more.

What are seaweeds?

Seaweeds are algae ('el-gay')

  • You may have seaweeds in YOUR HOUSE!
    Examples of algae found in ordinary people's homes:
    Your bathroom (if you don't clean it)
    Your aquarium (if you don't clean it)

Fascinating seaweeds!
Seaweeds are like weird life from another planet! 'Ordinary' plants have specific structures like leaves, stems, roots. Seaweeds don't have any of these and come in a wide variety of forms.

  • How many different kinds of seaweeds can you see around you?
    Describe their shapes, colours, patterns.

  • Who can find the biggest seaweed? The smallest?

  • Feel them. What do they feel like?
    A slimy coating or leathery surface reduces water loss when the seaweed is out of water at low tide.
    Some seaweeds are hard because they incorporate calcium into their bodies.
    Some seaweeds have a furry or velvety layer of fine hairs.

  • Smell them. What do they smell like?
    Some seaweeds have a funny 'medicinal' smell. Seaweeds also protect themselves from being eaten by containing unpleasant tasting chemicals such as iodine.
Seaweeds are important to the ecosystem
  • Food: seaweeds are eaten by many different kinds of animals. These include slugs, fishes and the Green sea turtle.
  • Shelter: many small animals hide among seaweeds. Some animals also lay their eggs on seaweeds.
  • Let's see if we can find some animals among the seaweeds? Be gentle when you look!
  • Food chain: These small animals are in turn eaten by bigger animals.
Seaweeds and you
"Can Eat or Not?" You have probably eaten some seaweed recently!

Can you think of some common food made from seaweed?
  • Agar-agar comes from seaweed. Agar-agar is used to make jellies.
  • Sushi is wrapped in seaweed.
  • Red seaweeds are a source of a substance used to gel and stabilise food such as chocolate milk and yoghurt.
  • Brown seaweeds are a source of a substance used to make food thicker, creamier and more stable. For example, to make smoother ice cream.
  • Seaweed in our everyday food look at the labels of the food products in your kitchen. Find out which ones contain extracts of seaweeds. Hint: look for words such as 'agar', 'carrageenan', 'alginate'.

Other uses of seaweeds

  • You can eat seaweed if you are a pig! Seaweeds are also fed to livestock. In the past, Sea lettuce (Ulva sp.) were collected in boatloads in the Straits of Johor, washed in freshwater then cooked and fed to pigs.
  • Seaweeds are also used as fertiliser to grow some of the food we eat.
  • Seaweed Farm! In some places such as the Philippines, there are farms growing seaweeds. For sale as food and for their important extracts. Seaweeds provide important income for these coastal dwellers.

Seaweed myths to dispel

  • Seaweeds are not 'weeds' i.e., they are NOT rubbish plants. They are an essential part of the natural ecosystem. And a vital part of the food chain that provides our seafood.

  • Seaweeds are not evil. While much media coverage may have been given to red tide and other sudden blooms of algae, most algae are harmless.
Handling tips

Don't step on the seaweed Seaweed is slippery and you might fall.

Thick layers of seaweed may conceal uneven surfaces, or hidden objects that might hurt you (e.g., broken glass) or trip you.

Many small animals hide among seaweed. You will squash them if you step on them.

If you HAVE to walk through a stretch of thick seaweed, go first and carefully test the ground before putting your weight on your foot. Ask the visitors to follow in your footsteps.

Don't dig or rip!
When asking visitors to feel or smell seaweeds, use pieces of seaweed that are already broken off or washed up on the shore.

Be gentle: Remind visitors to be gentle when looking at seaweeds. Small animals may be hiding among them. Delicate eggs may have been laid upon them.

Don't eat seaweeds on the shore Don't make visitors eat seaweeds on the shore. Some may have unpleasant substances, toxins or accumulations of heavy metals in them. The water they are in may also be unclean.
FREE photos of
Make your own badge here.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008