Approx 34% of uk coast. Exposed Atlantic headlands, sheltered sealochs and bays- varied micro-habitats tapestry of habitats Vertical zonation seems to exist on most rocky shores but communities that make up these zones differ depending on extent of exposure. Lose endless hours exploring rockpools. Variety of habitats and zones within. Deep and shallow tidal pools. Rocks that dry completely. Rocks that are only exposed at very low spring tides. Dark sheltered crevices. Wide open pools. Life very diverse Living things have to be adaptable. Tolerant or able to survive drying out dessication, temperature ranges – first life to leave the sea evolved here. Dries out twice a day. Spring tides neap tides. Increased salinity of pools evaporating. Declining salinity where fresh water flows in. Storms. Sea birds. Grazers. Not being able to photosynthesise or graze when the tide is out. Different degrees of exposure. Sheltered. Muddy. Exposed and stormlashed wave action. Getting nutrients from the water. Rapid recolonisation. Tidal changes- daily, monthly, seasonal Temperature changes- heat in summer and possible frosts in winter Dessication Exposure to wave action, sand scour, water circulation, sedimentation, O2, splach affected by fetch, prevailing wind, slope of shore, degree of facing into fetch, wind etc. Zonation- moderately exposed shores. Caused by factors above, competition, predation upper (eulittoral) middle and lower (sublittoral)
Explorers and seekers after sealife should be aware of tides. Replace rocks where they were found. Seashore code? Slippery. Seaweeds are the primary producers on the rocky shore, that is, they are the living things which use oxygen and sunlight to grow (ie photosynthesise) other living things graze on them. The variety of seaweeds on a typical shore reflects the range of conditions and tolerances of the seaweeds. Competition, growth rate. Also plankton for filter feeders.
(above Highest Astronomical Tide):
The very highest zone on the shore is called the splash zone, and as the name indicates this zone is not directly flooded with the rising water. Therefore, it has more in common with terrestrial habitats, although some of the animals move down to the sea to discharge their eggs or young at the highest spring tides. The dominant fauna is a few species of lichens which are fed on by two very small species of winkle. Highest band or zone on a coast. Lower limit marked by a line of barnacles- the first sea creatures. Splash zone- lichens
Lichens are the most obvious organisms in the splash zone, in more favourable environments they would be easily out-competed for space, light and nutrients by rapidly growing flowering plants. They are colonisers of bare rock and are slow growing but long lived. As they grow the action of acids and expansion of their cells can help to break up the rock into tiny fragments to produce a raw soil. This may then be colonised by mosses and as humus collects in crevices, by flowering plants able to tolerate the high salt content eg. thrift (Armeria maritima). This is an example of succession called a lithosere. White & Grey Lichen Belt Lichen Lichina pygmaea and Lichina confinis
Sea ivory lichen - Grey Lichen Belt
Tar lichens (Verrucaria species)
Yellow and Orange Lichen Belt
Also we have a special lichen section that describes many of the species found on the seashore.
Lichens are made up from two different organisms, a fungus and an alga, together they form a symbiotic, mutualistic relationship. Separately, they would require moist, sheltered conditions, together they survive in very hostile places. The fungal partner makes up about 80% of the lichen. The algal partner is almost always either a green alga (Chlorophyta) or a blue-green alga (Cyanobacteria). Some grow particularly well where there is a high nitrogen content eg. from sea bird droppings. Xanthoria may be prolific for this reason; The orange (eg. Caloplaca)...
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