Located 20km out of Portland; Bridgewater Bay has many secluded rock pool locations that are accessible to biologists for investigation. In this experiment, the aim was to study small sections of a rock poll that contained a distribution of organisms. These organisms that were located were found in the littoral zone of Bridgewater’s rocky seashore. A littoral zone is made up of a community of aquatic organisms habiting the narrow strip of coast. The organisms that were studied included periwinkles, sea stars, algae, urchins and different types of sea weed. Periwinkles have shells to reduce water loss and radiation effects. Sea stars also have a thick, impermeable outer layer to reduce radiation effects. Urchins are able to seek small crevices for shelter to reduce the drying effects of the wind. These are some of the structural and behavioural adaptions that rocky-shore organisms have. 1. Each region on the coast has a specific group of organisms that form distinct horizontal bands or zones on the rocks. The appearance of dominant species in these zones is called vertical zonation. It is a nearly universal feature of the intertidal zone.
Supratidal zone- When the tide retreats, the upper regions become exposed to air. The organisms that live in this region are facing problems like gas exchange, desiccation, temperature changes and feeding. It is only covered during storms and extremely high tides and is moistened by the spray of the breaking waves. Because of these severe conditions, only a few resistant organisms live here. Common organisms are lichens. When compared to our transect we found only types of algae and small black nerites.
Intertidal zone- The intertidal zone or littoral zone is the shoreward fringe of the sea bed between the highest and lowest limit of the tides. Because the intertidal zone is a transition zone between the land and the sea, it causes heat stress, desiccation, oxygen depletion and