Rocky Shore Zonation - Field Studies ?· Rocky Shore Zonation Zonation ... The gravitational pull of…

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<ul><li><p>Rocky Shore Zonation </p><p>Zonation..... the variation in the distribution of organisms caused by differences in both biotic and abiotic conditions along an environmental gradient. </p><p>Organisms living on the rocky shore have different adaptations to these factors and therefore will be able to survive at different heights on the shore accordingly. </p><p>Abiotic Factors Causing Rocky Shore Zonation </p><p>Desiccation: occurs as a result of emersion at low tide affecting the upper and middle shores. </p><p>Wave Action: more wave action means the water splashes higher and so the zones occur higher up on the shore. The strong force produced by powerful wave action will determine not just whether that organism can remain attached to the rock but also may have an effect on its growth. </p><p>Light: is needed for photosynthesis. Seaweeds need to be in seawater for this to occur. However, the water will filter off some of the wavelengths of light and reduce the intensity. </p><p>Temperature: immersion in water buffers against temperature change. Upper shore species will have to tolerate the greatest variation in temperature whilst it has least affect in the lower </p><p> </p><p>Rocky shore advantages </p><p>Theseashore </p><p> </p><p>The Rocky Shore ecosystem is very diverse due to the increased nutrients and light that come from being close to the surface. However, the organisms living there need to be able to cope with the tides. </p><p>TIDES The gravitational pull of the moon and the sun create a bulge in the ocean on either side of the earth. The earth then spins within this bulge creating two high tides and two low tides each day. </p><p>Method An Interrupted belt transect with 0.6m intervals running up the shore was used to assess the relative abundance of all the species present. ESACFOR abundance scale was used to describe the abundance of each organism within a 1m2 quadrat. The data could then be plotted on a kite histogram to clearly show the replacement of one species with another along the environmental gradient. </p><p>1 2 3 4 5 6 7 8 9 10 11 12 </p><p>Spiral Wrack </p><p>Egg wrack </p><p>Bladder wrack </p><p>Saw wrack </p><p>Gutweed </p><p>Sea lettuce </p><p>Irish Moss </p><p>Coralweed </p><p>Sea laver </p><p>Station number </p><p>Sp</p><p>ecie</p><p>s </p><p>A cross staff was used to move 0.6m vertically up the shore </p></li></ul>