An Investigation to show whether there is there a relationship between the number of dead barnacles and height up a vertical shore.
Abstract
The distribution of the two barnacle species Semibalanus balanoides and Chthamalus stellatus was studied to assess the correlation between the number of dead individuals and the vertical height above chart datum on a rocky shore environment. The number of dead barnacles was recorded at varying heights and the percentage of dead barnacles was then calculated. Using a spearman’s rank correlation coefficient it has found that there was no correlation between these two variables, and this was then explained using the change in the biotic factors such as the predation by Nucella lapillus. It was found that due to the presence of Nucella the percentage of dead barnacles was highest between 5.70m and 6.20m above chart datum and due to the rapid growth of Semibalanus in the lower shore, swamping was an effective method to increase the rate of survival in the lowest areas of the shore.
Aim
The aim of my investigation is to conclude whether there is a significant difference in the number of dead barnacles at different vertical heights above chart datum on a coastline and what ecological factors may cause this change.
Research
Barnacles belong to the Arthropoda phylum and Maxillopoda class (6).
In the British Isles there are two common species of barnacle, the acorn barnacle, Semibalanus balanoides and the Poli's stellate barnacle, Chthamalus stellatus(7) . Both of these species belong to the Sessilia order, which are barnacles without stalks, with Semibalanus balanoides being the most common (8). Semibalanus are a particularly small species of barnacle reaching approximately 15mm in diameter and consist of six grey white plates forming a shell wall, creating a diamond shaped opercular aperture.
Chthamalus is of the same size with six grey plates, although these plates create a kite shaped opercular aperture...