Seeds of the Sea

Tide too high to go out yet?
Raining and have to hide in the shelter on the high shore?
Here's some things you can do on the high shore.

Get everyone to collect seeds and other things they they can find. Give them a time limit or they will take forever. Come back and have a look at what they've found.

Three NAKED facts about plant seeds on the shores

naked fact #1: Shore plant seeds are Real Tough!

The seeds of shore plants often travel a long distance in the sea to find new places to grow.

Let's see some of the special ways they have to survive this long and dangerous journey.

Thoughtful question: Imagine you have to travel miles and miles in the sea. What do you need to survive?

• Food
• Water
• Ability to float
  

Talk about these features for the seeds that you might find.

A: Seedling of the Avicennia mangrove tree, already starting to grow
B: Fruits of the Rhu tree
C: Fruits of the Sea Almond tree
D: Part of the ball of fruits of the Nipah palm, already starting to grow
E: Seed pod of Derris, a climber of the mangroves
H: Part of the seeds found in the round cannon-ball like fruit of the Xylocarpus tree
I: Part of the ball of fruits of the Seashore pandan
J: I have no idea what it is


naked fact #2: Staying with mama until they are teenagers?

Some mangrove seedlings are already half grown when they fall off the mama tree
F: Rhizophoa
G: Bruguiera gymnorrhiza

Unlike other seeds which don't start to grow until they drop off the mama plant.

On some mangrove trees (Rhyzophora, Bruguiera) fruits start to shoot while still on the tree. They look like 'long beans' on the tree. Others like Avicennia are also growing inside the fruit and quickly sprout once they leave the mama tree.


naked fact #3: Being long has its advantages!

Trees have to breathe. Being tall means the seedling gets above water more rapidly and can breathe sooner as the tide falls.

Common misconception: It is not true that the long pointed seedlings fall off the mama tree and stab into the mud to grow. It's not good to grow in the shade of mama, for both mama and baby trees.

Ideally, the seedlings would drop off at high tide and float away lying horizontally. With time, the tip gets water logged and starts to dip downwards. Eventually, when they arrive at a good spot, roots grow from the tip and right the seedling in a vertical position. Leaves then sprout from the top.

Dead snail shells: Violent deaths!

Violent NAKED facts about dead shells

Stuck in a shelter waiting for the rain to stop? Came too early and the tide is still too high to go out to the flats? Here's some stories of death and violence to entertain your restless visitors with.

First go out and quickly gather some of these shells that tell the story.

(The striped stick at the top left corner is a spine of a sea urchin. Living sea urchins are covered with a skin. When they die, the skin rots and their spines fall off)

Snail shells are generally coiled. (Show some other broken shells of typical snails with their coils exposed).

The cowrie doesn't look like it has a coiled shell from the outside. But inside, it is coiled!

Thoughtful question: Why do you think the top of this cowrie shell is broken?

It was probably crunched off by a hungry crab!



All these shells have similar breaks at the top.

Thoughtful question: What do you think happened to them?

You're right! A crab probably crunched them too!

Many snail-eating crabs have two different kinds of claws. One large crunching claw, and another claw with thin pincers that act like chopsticks to pick out the snail snack.


See the hole in this clam shell? And the break in the other?

Thoughtful question: Oh dear! What happened to these clams?

The hole was probably drilled by a clam-eating snail, like a moon snail. The moon snail produces an acid that softens the shell. It then uses its rough file-like tongue to slowly drill a hole. The clam is then pumped with digestive juices and is sucked up like soup. Yummy!

The big broken clam was probably crunched by a crab.