In the following study, rock pools from the upper and lower shore of Bracelet

Bay, were examined and the organisms within noted. The contents of the two pools were compared. The abiotic variations of the pools were recorded and examined in an attempt to understand why the contents of the pools differed.

A greater abundance and variety of organisms was present in the lower shore rock pool, this was due to the lower rock pool being a more benign environment than that of the upper shore. This was related to the exposure time of the two pools. The rock pool of the upper shore was exposed for longer and therefore suffered greater from variation of abiotic factors, as a result, the organisms of the upper pool had to possess special adaptations to colonise the area. The lower rock pool generally contained different species

which could out compete the organisms of the upper pool when in a more benign environment.

The rock pools studied should both contain organisms specially adapted to live in the intertidal environment of the rock pools. The organisms need to be adapted to the microenvironment of the rock pool, as conditions are considerably different to those of a 'normal' marine e

nvironment. The rock pools spend some of their time completely submerged by the sea and other times exposed to the air. When exposed the organisms of the rock pool are part of a much smaller body of water than normal. This smaller volume of exposed water is likely to be changed significantly, mostly as a result of heating by the sun (Brehaut, 1982).

Green algae is generally thought not to prosper when greatly submerged, as less red and blue light is available, resulting in a decrease in photosynthesis rates, (Begon et al 1986). IN fact, green algae sporelings show much reduced rates of growth, when subjected to low light intensities. Contrastingly, red algae sporelings showed an increase growth rate at low light intensities, (Begon et al 1986). The results reflected this fact to a degree, as, in the intertidal region studied, green (and blue) algae dominated, with red algae only being found in the lower shore. The lower shore rock pool was much shallower than the upper, but the overwhelming presence of green and blue algae in the deeper rock pool suggests that, the time the pools are covered by the sea, may be a more important factor when it comes to rates of photosynthesis.

One rock pool from the upper shore and lower shore were chosen. The physical features of the rock pools were recorded. The shape of the pools were drawn, the surface area of the rock pools worked out by measuring the dimensions of the rock pool with a metre rule and string. Pool volume was calculated using the measurements for the pool depth and surface area.

As expected, all the organisms found in the rock pools had methods of protecting themselves against wave action. The algae had strong holdfasts, the gastropods adhesive foots using suction and in some cases secretion as well, (e.g. Patella), (Brehaut, 1982). Some of the organisms have adapted body shapes as well, e.g. the short shell of L. littorea.

Some common words found in the essay are:
Raffaelli Hawkins, Boaden Seed, Bracelet Bay, Patella Littorina, DISCUSSION Results, RESULTS Species, Recording Temperature, Patella Brehaut, rock pool, upper shore, lower shore, rock pools, Enteromorpha Fucoids, shore rock, shore rock pool, brehaut 1982, upper rock pool, upper rock, lower rock pool, lower rock, Harper Townsend, lower shore rock, boney 1969, upper shore rock, organisms upper,
Approximate Word count = 3208
Approximate Pages = 13 (250 words per page double spaced)