Investigating Limpets on the shore:
Sheltered vs. Exposed
Patella vulgata (common limpet) is one of the most well known organisms to inhabit the intertidal zone. The intertidal zone is the area of the shoreline which is exposed to the air at low tide and can be submerged at high tide. Limpets inhabit the whole of this area ranging from the high zone (upper littoral zone) to the shallower parts closer to the sea. Furthermore, they can be found on rocky shores of all degrees of exposure to wave action and because of this, they have developed methods of tolerating the battering action and removal by rocks and powerful waves by having a hard, stream lined shell and remarkable suction power of their muscular “foot”, used to cling onto surfaces.
During the day they can remain “clamped down” to the rock, whereas in the night they graze the algae growing on its surface. It is the most important herbivore in restricting the growth of algae, however, like any other species of snail, it leaves a slime trace which helps to stimulate algae growth.
There are a number of possibilities to look into when investigating limpets on the shore. For example, I can study the amount of limpets which inhabit both sheltered and exposed areas on the shore or even the angle of their shells (I believe these will differ as the limpets which are exposed may need to have flatter shells in order to prevent removal from their rocks by wave forces). However, I have chosen to study a feature of limpets which is similar to investigating the angle of their shells and would most likely differ between sheltered and exposed areas of the shore… this feature is the height of the limpets. Therefore, the aim of my investigation is:
To investigate the differences in the shape, more specifically the height of limpet shells on the shore. Comparing the heights of those that inhabit the areas exposed to the sea to that of those that are sheltered by rocks.