Do You Know?
On the beach and shores around Gozo, we find many seashells. Do you know that they were once a home to small, soft-bodied creatures called molluscs? And do you know how molluscs make their shells?
What are Molluscs?
Molluscs are small marine creatures such as scallops, mussels, clams and oysters. Some molluscs do not have a shell, for example, the Octopus. Other types of common shells include snail shells, crab shells and even turtle shells.
All these animals make their shells in many different ways. Let us look at the molluscs who live in the sea and build their shell from scratch. By the way, they keep on building their shell their whole life long!
How do they build their shell?
Once the baby molluscs hatch from tiny eggs, a few days later they begin to build their shell, layer after layer. This is a long process and requires constant enlargements. As the inhabitant of the shell grows, it must keep on building it bigger, this process is a life long exercise.
Molluscs use special ingredients, like proteins from their bodies to build the shell. Chemicals, such as calcium, carbonate and salt come from the sea.
One part of the mollusc’s body constructs the shell, this special part is the “mantle”. First, the mantle builds a kind of frame, using its body proteins to make a sturdy and strong construction. Once the framework is in place, the mollusc fills it with calcium and carbonate from the sea. These are the same components that our bodies use to make our bones and skeletal framework.
As the mollusc grows inside its shell, it will need to enlarge and extend it to make it fit. They do this by adding new layers of the chemicals – calcium, carbonate and body proteins. Molluscs add on new layers to the framework, making the shell larger and longer as required.
The newest section of the sea snail’s shell will appear at the opening where the inhabitants head pokes out.
Seashells are Important for Our Planet;
During its life in the sea, the mollusc’s shell often becomes damaged or broken. A mollusc’s body produces protein and gets the calcium and carbonate to repair the damage.
When a mollusc dies, the soft body parts disappear or they fall prey to predators. Overtime, empty seashells will wash up on the shore. Sometimes they there dropped there by sea birds on the wing.
You will find seashells laid around on the beach close to the tidal area. As you know, there are many types of seashells in lots of different colours, shapes and sizes. The size and shape state which type of animal once lived in there.
Over generations, molluscs have grown a certain design and type of shell. This shell, which they make is suitable for the environment they live in. Shells might be there to help protect the mollusc against predators that wish to eat it. Other designs enable the molluscs to dig down in the sand or seabed to escape their enemies. A molluscs shell colour depends on what the molluscs have eaten. You find many different coloured varieties strewn along the coastline and sandy beaches.
Sometimes, seashells on the beach still have inhabitants inside. If this is the case, please leave the shell there and allow the animal to go about its life.
Seashells are also important to our planet and to other marine animals who live in the sea. For example, young fish or small hermit crabs use discarded, empty shells and make them their home. Seabirds and other land-living birds use seashells to build their nests. They are sturdy, waterproof and light enough to carry back to their nests.
Rather than collecting empty seashells, a better choice is to take photos instead. Leave the shells in place for other animals who need them more than you do!
Better still, come and try out scuba diving. This enables you to see the marine animals in their natural habitat. Sign up for a Discover Scuba Diver course and experience the wonders of our underwater world. The course takes around 3 – 4 hours.