Rock On! (Investigating the Rocky Shore)

On this ecology field trip, I got the chance to visit and study a Rocky Shore ecosystem off the cost of the PranBuri beach. It was a hot and very sunny day, but the sky was clear and the conditions were perfect for a field experiment.

The Rocky shore is a unique ecosystem. It's an ecosystem that is continuously facing changes due to the tidal nature of the water that it's submerged in. Usually the Rocky Shore ecosystem extends many meters out into the ocean from the seashore and faces persistent change in their environment because of the the ocean's high and low tides. Marine organisms can survive in this continuously changing environment because they have unique adaptations that allow for them to withstand the dry conditions during the low tide and saline conditions during high tides. The organisms that live within the intertidal zone have to face these extreme environmental conditions, and thus have developed sufficient adaptations that allow for them to thrive.


The most abundant animal that I saw on the rocks of the shore was the barnacles (seen in the picture on the top right right). They are small marine organisms that thrive by attaching themselves to the walls of the rock. The cone shaped body structure of the barnacles and their hollow middle resembles a volcano. Due to the periodic nature of the tides, the hollow middle is an adaptation against water loss during periods of low tides. The hollow entrance is covered by valves that close to prevent water loss during dry periods. Their hard double layered shells are used as protection during high tides against the strong ocean currents.

The periwinkle snail was another organism that could be easily spotted. They are quite small, much like the barnacles are, and had adaptations that allow for them to thrive within the intertidal range of the rocky shore. Periwinkle have muscular foot that enables them to move and seek shelter from the hot sun during low tides. They seek shelter under and between rocks from the excessive heat. Their thick calcium shells allows for them to withstand the constant crashing of the waves that most rocky shore organisms have to endure. On this ecology field trip, the distribution of periwinkle snails were studied using a continuous transect belt. The data for the distribution of the periwinkles along the transect are shown below.

The graph shows that there is no correlation between the two continuous belt transect. The distribution of mangrove periwinkles ( the side to the left is furthest away from the shore) varied between the two transect. In the transect represented by the pink kite diagram, the majority of the mangroves were concentrated in deeper water. The periwinkles were distributed evenly across the second transect, represented by the orange kite diagram. 

The data collected for the experiment is accurate to merely a certain extent. It's difficult to try and count the number of periwinkles that are submerged in water. As they could be easily miscounted, the distribution of periwinkles along the rocky shore should be further investigated by constructing more transect along the shore to assess whether there is a correlation between the number of periwinkles and the distance from the shore. 

"Seashore - A Rocky Seashore Ecosystem." :: Environmental Facts. Young Peoples Trust for the Environment, n.d. Web. 18 Nov. 2012. <http://www.ypte.org.uk/environmental/seashore-a-rocky-seashore-ecosystem/98>.