Hypothesis: The population of Littorina saxatilis is greater in the middle zone.
Aims of study: This experiment is being conducted in order to determine if the population of Littorina saxitilis is greater in the middle zone. My reason for this hypothesis is that the Littorina saxitilis" main source of nutrition is the Fucus vesiculosus which is found in large quantities in the middle zone.
Background on hypothesis: Littorina saxitilis is found on the upper eulittorial zone, down to the littoral fringe. They are typically found under bedrock, empty barnacle shells and under rocks. This is so they can reduce the drying effects of the wind. They can also be found on salt marshes and mud banks. They usually attach themselves to Fucus. Littorina saxitilis is a highly polymorphic species, they are found in southern Brittany and the British isles.
L. saxatilis is able to withstand harsh conditions; they have a protective plate known as the operculum which tightly closes the opening of their shells. On dry land L. saxatilis can cement the edges of its shell to rocks and plants using gluey mucus, so that when the tide comes in or out they can avoid being washed away. They can also avoid dehydration as they have a thick impermeable shell that reduces water loss and radiation effects, and their metabolic rate can be lowered during exposed periods to minimize oxygen consumption. They ensure the survival of their species by keeping its young inside its shell, in a chamber until they can take care of themselves. .
Littorina saxatilis are found mostly on the upper levels, because of their interactions which exist between them and other organisms along the tidal continuum. If L. saxatilis are in competition with another species such as the conniwink, and they are more successful, then the number of L. saxatilis will be much lower, or they can exclude them all together. Distribution patterns are therefore a result of adaptations and interactions.
