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The swamp script

This audio is called The swamp.  It belongs with the unit Living things, Set 2 Lesson 10.

(music)

Narrator   Have you have been to a mangrove swamp?  It’s a very special place. There’s nothing else like it. This is a chance for you to get an idea of what it’s like in a mangrove swamp.  You may not have had the pleasure of losing your gum boots in the dark, sticky mud that smells rotten, swatting dozens of blood-sucking mosquitoes, dodging huge spider webs whilst picking your way around numerous crab burrows.  Come to think of it, this is probably the best way to study mangroves!  But why are we going to this trouble?

We are going to learn about mangroves – what they’re like and why they’re important.  And this is a really good opportunity to revise what we’ve learned so far – observing, looking for similarities and differences, classifying plants and animals and writing food chains.

As you listen to the tape, try to work out why mangrove swamps are so important.

(music)

Pretend you are with the students that are on this excursion. You are all with your teacher, ready to go into the mangroves.  Your teacher will be guiding you – helping you with the activities, asking questions and explaining things so you understand.

(pause)

Teacher   We’re going into the mangroves.  We all need to  keep very quiet so we don’t scare any of the animals away.  You’ll have to keep your eyes open and observe very carefully if you want to see anything.

  Let’s go.  Nice and quiet now. Shh!

(walking…)

Student     What are all those things sticking up?

Teacher   Good question.  Look at the soil.  What is it like?

Student  Wet, muddy, sticky.

Teacher   That’s right.  Do you think that there is much air in there?

Student  No no, not really.

Teacher   Yes, your right.  Not much air can get through the water and the mud is really sticky.  The mangrove roots grow straight up out of the mud so that they can exchange gases. Gases like oxygen and carbon dioxide can go in and out of the roots.

We can see thousands and thousands of roots.   These roots everywhere are really handy for the animals that live here.  Any ideas why?  Can you see anything on the roots?

Student Yeh, it looks like a shell or something stuck on the tree.

Student  Look!  There’s a crab.

Student  There are a few very small fish, I think, swimming around there too.

Teacher   Good observations.  Mangroves provide a home for small animals.  In the water around the roots, it's hard for big fish to get in to eat them.  And shellfish can attach themselves to the trees.

(pause)

Teacher   Doesn’t it seem a little strange to see trees growing in the water? And large trees like that!  What types of plants do you usually find living in water?

Student   Ah, seaweeds, algae, I know kelp, bullrushes, reeds, seagrasses.

Teacher    Good they are all correct answers.  Does anyone know any other trees, besides mangroves, that live in salty water? There are not many trees that can live in conditions like this.  Mangroves are one of the few land plants that can live in shallow salty water.

Those people that are near a tree, have a close look at the leaves. What can you see on the surface of the leaves?  What do you observe?

Student  There are white things – crystals.  They look like salt or sugar or something like that.

(pause)

Teacher   Touch the leaves.  Now lick your fingers.  How do they taste?

Student  Yuk.  They’re all salty!

Teacher   That’s because mangroves take in salty water through the roots.  Then to get rid of the salt, they excrete the salt through the leaves.  Too much salt would kill a normal plant.

What I’d like you all to do now is to record your observations.  So get out your excursion notes and write a description of the mangrove environment.  Find the place where it says ‘Describe the mangrove environment’.  There is space below this for you to write your description.

(music)

Student  You mean you just say things about salty leaves and stuff like that?

Teacher   Yes, that’s right.  Write down what you think is special about this place.  What features of this place make it different?

Student  Like it’s muddy, salty water…

Teacher   Yes, a muddy, salty environment.As you came into the mangrove area, you would have seen lots of different animals.  Did you see all those spiders?

Student  Yeh

Teacher  Look over there, the are are about a dozen or so great big webs.  What do you think those spiders are catching in their webs?

Student  Flies, beetles, insects.

Teacher   Lots of different sorts of insects, probably.  Notice, though, that there is lots of evidence around here about animals, even though we can’t see them.  Look at the leaves.  What’s happened to them?

(pause)

Student  Looks like something has been chewing them Miss.

Teacher   What do you think it could have been?

Student  Snails, worms, caterpillars, insects.

Teacher   OK.  Let’s look more closely at those spider webs.

Student  Do we have to?

Teacher   Yes, but be careful!  These are jumping swamp spiders! Only kidding.  You will have noticed lots of little balls though.  What do you think they might be?

Student  Eggs, insects.

Teacher   Yes, insects are caught and wrapped up until the spider is ready to eat them.

Student Ooh

Teacher Yeh a bit creepy isn't it?

Teacher   Does anyone know another way to identify animals in the swamp?  If you’re very quiet what can we do?

Student  Hear them.

Teacher   OK.  Let’s be very quiet and listen for some more animals.

Student  Look, there’s a dragonfly.  Shhh!

(cricket calls)

Student  Crickets, bugs.

Teacher   If you listen carefully you might hear some birds.

(bird calls)

(pause)

Student  I can hear one!  I wonder what it is?  Could be a crow.  I saw one earlier.  I saw a pelican and an ibis too.

Teacher   There are a lot of birds that eat fish near a mangrove, swamp ibis, cranes, stork, pelicans.   Now I’d like you to turn to your excursion notes again.  This time find the place where it says ‘List the animals that you have observed on your walk through the mangroves’.  Can you fill that in now, please?

(music)

Student  Miss, did you mean animals like crabs and birds, spiders?

Student  Insects?

Teacher   Anything else?

Teacher   How can we tell the difference?

Student  Let’s catch some.

Teacher   OK.  Here are some nets to scoop up the water and whatever is in there.  Put your animals in these dishes, with some water. Then you can use the hand lens to see the animals more clearly.

Student  But how can we tell what we’ve caught?

Teacher   well, in your notes, there is a chart with drawings of the animals that could be in the water.  Have a close look at your animals and identify them using the chart – it’s called ‘Water animals’.

(pause)

Student  We’ve caught something.  It’s got lots of legs.  And it’s moving quite a lot.  Its body bits are all joined on together.  But it could be lots of things.  Dragonfly nymph, or a mayfly nymph, crayfish, damselfly nymph or a shrimp.  Its got long feelers in the front of its body but no claws.

Narrator   So what do you think it is?  I think it’s a shrimp, don’t you?

Student  What do these tiny water animals eat?

Teacher   Well, the small fishes eat the shrimp and the insect larvae like the mosquito larvae.  We definitely know that there are mosquitoes here!  I don’t know about you but I’ve been bitten lots of times.  The crabs, shrimps and insect larvae eat mangrove leaves that have rotted away.  And the crabs are eaten by the birds.

Student  Yes, that’s right.  I saw a dead crab with its guts missing back there!

Teacher   The next activity is to write as many food chains as you can from what we’ve observed and talked about on our way through the mangroves.  You can use the list of animals that you wrote down as well as the ones we’ve just caught out of the water.

Are there any questions?

Student  How do we start?

Teacher   How do all food chains start?

Student  A plant.

Teacher   Yes.  What plants are there in this environment?

Student   Mangroves.  That’s about all you can see.

Teacher  Right, there is a space for you to write your food chains in the excursion notes.  The heading is ‘Food chains’.   I’ll give you five minutes to write down as many as you can.

(music)

Teacher   Now the last thing we need to do is try to work out why the mangrove environment is important. Has anyone got any idea?

Student  Maybe this is a good place for small fish or baby fish or prawns and stuff like that.

Teacher   Yes, that is a good observation.  There are a lots of baby animals in this area.  If there were big fish around they would eat the little fish. So, this area acts as a kind of nursery.  Large carnivores can’t live and hunt small fish in here, so the small fish are protected and can grow up to be big fish.  They wouldn't be able to do that out in the open water.

Anything else?

Student  There’s lots of mud and stuff here.

Teacher  Yes that’s right.  The mud accumulates here– builds up. 
Eventually this area could change into more solid land and support different kinds of life.  So the mangroves are land builders as well as fish nurseries.

What would it be like here in a storm do you think?  How would it be different from the actual coastline, the beach.

Student  It wouldn’t be so windy.  It would be more sheltered.  Less sand would blow away.

Teacher   Yes that’s right, so the mangroves are protecting the coastline from erosion – what I mean is, the wind doesn’t blow the soil and sand away, especially during storms.

Use these ideas to write down the reasons you think mangrove swamps are important.  On your excursion sheets, there is a space for you to write your ideas under the question ‘Do you think that mangrove environments should be protected?  Give me some reasons for your answer.’

(music)

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