Due Date: 03/09/2010
On the 23rd of August, the three biology classes or grade 11 at Redlands College visited the rocky shore ecosystems at Point Cartwright in Queensland. Two different types of rocky shore ecosystem were examined, the rock pool area, and the boulder area. We first examined areas within the rock pool area. The rock pool area has several specific features which set it apart from other rocky shore ecosystems, including its geological makeup and position. It is made up of a flat platform of rock pockmarked with numerous rock pools; indents in the rocks which are filled with water and contain numerous forms of marine life. These pools can vary in size, from small cracks in the rock which have a changing water level or huge crevices which almost always have a level of water in them. Each rock pool has different species of marine life, in varying numbers. The platform lies at the base of a cliff, and is usually sheltered from the constant barrage of waves, except occasionally at high tide when the occasional wave will replenish the water in each rock pool. However, the platform can become quite windy, as there is no shelter from an onshore wind. The classes from Redlands College were constantly buffeted by the onshore wind while they were there, giving them an idea of the sought of conditions the pools are subject to every day. These abiotic factors define the type of organisms present in the rock pool area as the organisms need to withstand the effects of the abiotic factors and still be able to carry out the processes required for them to survive. The effect of each abiotic factor and resulting population in each area will be examined in more detail later in the report. The second ecosystem examined was the boulder area. The boulder area consisted of a number of boulders clumped together on the sandy shore at Point Cartwright beach in the inter-tidal zone. The boulders themselves were all clumped together, forming small pools of water whose water level changed with the flowing tide. As they were on the shore, they were constantly buffeted by waves; however, the boulders provided some degree of shelter from the waves. The boulders closer to the shore were dryer, except as the tide flowed out, small pools would form which could contain marine life. These pools would be unaffected by the tide, but were less sheltered, and could be venerable to evaporation. Each area, and the organisms present were affected by both biotic and abiotic factors, which set the areas apart and helped to define each one.
From the data collected from both the boulder area, and rock pool areas numerous and varying trends and relationships within the data can be identified. The most prominent of these is the difference in the species of the organisms present in the rock pool and boulder areas. Whilst some organisms lived in both areas, there were others that only lived in their specific area. Organisms like anemones, sea urchins and zoanthids are all organisms that were present in the rock pools, but not in the boulder area. This can be contributed to the abiotic factors and differences in these factors in each area. The rocky pool area is relatively sheltered from wave action which allows more soft bodied organisms which cannot constantly be buffeted by waves such as zoanthids and sea anemones to live without being carried off their rocks by a current. Another difference in the abiotic factors of each area is water. In the rock pools, there is constant water as most of the pools do not have a draining passage, and are filled up by the occasional wave that breaches the platform. Organisms like zoanthids, sea urchins, and anemones require constant water to survive, which is why they thrive in areas such as rock pools. Some zoanthids that were on the edge of the rock pool had emerged from the...