step on the seaweeds!
'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
What are seaweeds?
Seaweeds are algae ('el-gay')
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)
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.
are important to the ecosystem
many different kinds of seaweeds can you see around you?
Describe their shapes, colours, patterns.
can find the biggest seaweed? The smallest?
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
Some seaweeds have a furry or velvety layer of fine hairs.
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.
- Food: seaweeds
are eaten by many different kinds of animals. These include slugs,
fishes and the Green sea turtle.
many small animals hide among seaweeds. Some animals also lay
their eggs on seaweeds.
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.
"Can Eat or Not?" You have probably eaten some seaweed
Can you think of some common food made from seaweed?
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.
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'.
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
are also used as fertiliser to grow some of the food we eat.
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.
myths to dispel
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
are not evil. While much media coverage may have been
given to red tide and other sudden blooms
of algae, most algae are harmless.
Don't step on the seaweed Seaweed is slippery and you
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.