ZONATION

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0><tr> <td valign="top" height=115 BGCOLOR="#66CCCC" TEXT="#080000" bgproperties="fixed" background="03500730ezvthe.gif"> <div> <FONT SIZE="4" COLOR="#CCFFFF" FACE="Arial" ><B>The wonders of the weeverfish ( T.vipera )</B></FONT><B>|   </B><A HREF="index.htm" TARGET="_top" TITLE="Wonders of the Weeverfish (Trachinus vip"><U><B>home</B></U></A></div> <div> <A HREF="id72.htm" TARGET="_top" TITLE="Marine photographs"><U>Marine photographs</U></A>   |   <A HREF="id87.htm" TARGET="_top" TITLE="Marine Environments"><U>Marine Environments</U></A>   |   <A HREF="id131.htm" TARGET="_top" TITLE="Rockpools"><U>Rockpools</U></A>   |   <A HREF="id94.htm" TARGET="_top" TITLE="SANDY SHORE"><U>SANDY SHORE</U></A>   |   <A HREF="id143.htm" TARGET="_top" TITLE="Movies"><U>Movies</U></A>   |   <A HREF="id97.htm" TARGET="_top" TITLE="MUD SHORE"><U>MUD SHORE</U></A>   |   <A HREF="id134.htm" TARGET="_top" TITLE="Man Made"><U>Man Made</U></A>   |   <A HREF="id150.htm" TARGET="_top" TITLE="Marine Colonisation"><U>Marine Colonisation</U></A>   |   <B>ZONATION</B>   |   <A HREF="id140.htm" TARGET="_top" TITLE="Q A"><U>Q & A</U></A></div> <div> </div> </td> </tr><tr> <td valign="top" height=365 BGCOLOR="#66CCCC" TEXT="#080000"> <div> <B>ZONATION</B></div> <div> Any Marine coastal environment can be divided into distinct zones. These zones are determined by a number of factors such as tidal range (High and low tide), Individual species range or a combination of the two. For simplicity the Marine zonation referred to on this web site is Inter-tidal zonation and is described below. This model is the basis of all most if not all the Inter-tidal zonation modals and is referred to in a large number of text books. </div> <bR> <bR> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="382614e0.jpg" border=0 width="609" height="334" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <bR> <div> As you move up from the waterline to the land the coastline can be divided into 4 distinct zones; <B>Infralittoral zone</B>, starting at the extreme low water spring tide (ELWS) to the Low tide mark. <B>Mid-littororal zone</B>, consisting of the area of coast covered by the Normal tidal range, <B>Supralittoral zone</B>, From the high tide mark to the extreme high water spring tide (EHWS).</div> <div> <B>Splash zone</B>, the area of land that is never covered by sea water but is affected by the water due to wave action and sea water spray. </div> <bR> <div> Plant and animal species have to compete against the elements and each other for every inch of available space on the shore. The upper range of any given species is controlled by the environmental effects (physiological) such as desiccation and salinity changes. The lower range of any species is controlled to a greater extent by predation and competition (biological), that is the faster growing seaweed's out compete other species by shading out the slower growing species of seaweed. These species however are better suited to being uncovered by sea water (resist the effects of desiccation) and can live further up the shore. </div> <bR> <div> Although this is generally true zonation is determined by a complex interaction of any species with a number of others as well as environmental factors. The above statement is a simple one and the reason for the zones in any given environment are varied and have to be studied in detail. The most influential factor can also change throughout the year e.g. there may be a higher concentration of predators in the summer months than the winter and therefore exert a greater biological pressure in the summer months on any given species. In the winter the lower temperatures may control the abundance of species (a larger difference between sea water temperature and air temperature).</div> <bR> <div> There are also micro-environments present on a rocky shore where species can live outside their zones. These micro environments are called rock pools and are usually more abundant the lower down a shore you travel. These rock pools also trap other species (fish, shrimps etc.) when the tide ebbs only to release the trapped occupants again when the tide flows back in.</div> <bR> <div> <A HREF="id132.htm" TARGET="_top" TITLE="Berts Safety Tips"><U>Bert's Safety Tips</U></A> An area of my site designed for the young who want to go and find the Marine organisms mentioned on this page. This area contains safety tips whilst visiting this environment.</div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <A HREF="id67.htm" TARGET="_top" TITLE="SITE INDEX"><U><IMG SRC="3128bd30.jpg" border=0 width="139" height="211" ALT="SITE INDEX LINK" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></U></A></div> <bR> <bR> </td> </tr></table></body>