Rocky shores are biologically rich environments, and make the ideal natural laboratory for tudying intertidal ecology and other biological processes. Because they are so accessible, they have been studied for a long time and their species are well known. There are a large number of factors that favor the survival of life on rocky shores. Temperate coastal waters are mixed by waves and convection maintaining adequate availability of nutrients. Also, with the effect of the tides, the sea brings plankton and broken organic matter in with each tide.
The high availability of light and nutrient levels means that primary productivity of seaweeds and algae can be very high. Human actions can benefit rocky shores with nutrient runoff. Regardless of the factors that favor life on rocky shores, there are a number of challenges those marine organisms, which use them as their habitat, must face. Generally, the distribution of its benthic species is limited by salinity; wave exposure, temperature, desiccation and general stress.
The constant threat of desiccation during exposure at low tide can result in dehydration which many creatures have developed strong adaptations to prevent such as production of mucous layers and shells. Many species use shells and holdfasts to provide stability against strong wave actions. There are also a variety of other issues such as varying temperature fluctuations due tidal flow, changes in salinity and various ranges of illumination which can make life very difficult for rocky shore organisms. This can be coupled with predation from birds and from other marine creatures and also the vast effects of pollution.
Many animals and plants live on rocky shores in the area between high and low tide called the intertidal zone. These organisms must be able to cope with problems of not one environment, but two. They are pounded by waves, exposed to extremes of temperature and salinity, nd flooded by seawater and exposed to drying air twice every 24 hours. They also have to avoid being eaten by birds, molluscs and crabs at low tide, and by fish and other marine life at high tide. Several distinct habitats exist in rocky shores, each with its own survival challenges for plants and animals living there.
As well as providing homes for many animals, rocky shores are also an important nursery area for many fish and crustacean species. Some of these species like to shelter by rocky shores, in areas where stands of seaweeds break the waves'' power. This habitat also provides lots of food for fish. The commercially important fish found around rocky shores include blackfish, yellow fin bream, snapper, tarwhine, trevally, yellowtail and sampson fish. Algal beds of this habitat are an important food source for rare and threatened species like marine turtles.
And at low tide, wading birds love to feed on 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. Upper Shore Zone (around Mean High Water Springs): This zone is only immersed by the spring tides, and then only for a short time.
Two brown seaweeds, the Channelled Wrack, Pelvetia canaliculata, and the Spiral Wrack, Fucus spiralis, have adaptations to prevent drying out and can survive when the tide is out. Acorn Barnacles settle in this zone. 0 Middle Shore Zone (around Mean Tide Level): For half the day the tide will be in, even during the period of neap tides. The ommon brown wrack of this zone is the Bladder Wrack, Fucus vesiculosus. Mussel beds will form and both limpets and periwinkles will graze the rocks. Beadlet Anemones are resident and Shore Crabs will be found from spring to autumn.
Lower Shore (around Low Water Neaps): For most of the day the sea will cover this part of the shore, so that the rockpooler will need to consult his tide tables to ascertain when the shore is accessible. This will be longest during the spring tide period. The important brown seaweed is the Serrated Wrack, Fucus serratus, which straddles large areas where there are suitable attachments. The range of crabs, molluscs, small fish and prawns is much greater in this zone. Independent Variable: The different distances (every 5 meters) as we get further away from the seashore. This would be measured with a transect line of 50 meters.
Dependent Variable: The variety of species and vegetation found at every 5 meters along a 50-meter transect line. This would be determined by counting the number of species and vegetation found per quadrat. The types of substrate found under the 50 meter transect line at 5-meter intervals. Control Variables: Same distance measured away from the shore (5 meters) with the help of flags and a ransect line. If the distances were not kept the same, then my results would be unreliable and inaccurate. I would control this by using a 50m transect line and placing a flag after every 5 meters accurately.
Same sized quadrats used for all measurements of the species as different size of the quadrat would mean that our counting of species would be different for all distances, which would result in unreliable data. I would use the same quadrat with 100 squares, in which each square would equal 1%. Same individual identifying the substrate type and counting he number of species found per quadrat as if different people count and identify the species and substrate type then the human error rate would increase and affect the results as different people have different interpretations thereby only one individual is suitable.
Use the same bearing device (compass) and the same individual to find the correct bearing for the transect line to be placed as if there are different people doing it, then there are higher chances of human errors to occur. I have to make sure that the same equipment is being used including the compass, different results, making them unreliable. Risk Assessment: Dehydration due to high sunlight and not enough intake of water Sun Burn can be caused due to the sunrays, which can also lead to sunstroke and fainting.
Getting stung or affected by the organisms present at the rocky shore that can be harmful and can also cause death. Safety Precautions: Wear snickers and no flip flops to avoid any scars caused by branches or species Distinguish the species, using an identification sheet before touching them as they can be harmful Wear gloves to avoid any sort of contamination Wear full pants or long socks in order to avoid any stings by different species Wash our hands with soap and water at the end. And sanitize them as well Drink a lot of water and apply sun block to keep safe from sun burn and dehydration.
Apparatus Used: Transect Line (50 meter long) 2 quadrats (100 squares in each) Compass 10 flags Pen and a clip board with paper Results table Species and Vegetation identification sheet Method: Use a compass and find the right bearing to make sure that the transect line would be placed straight on the shore (going up the shore) and not curved. Untangle the transect line and lay it straight on the shore according to the bearing found. Place a lag at O meters and the next one at 5 meters. Do this for every 5 meters until you reach 50 meters.
Place the quadrat in such a way that the flag is in the first box of the quadrat and the quadrat is placed on the right side of the transect line. Create a results table with a column each for distance, substrate type, species and vegetations. Count and identify the number of species and vegetation found in each square using identification sheet and write the results in a table. Also, write the type of substrate found. Each square of the quadrat represents 1% of the total number of species or vegetation found. Now do this with every flag placed on the transect line.
The method will be repeated at least 5 more times in order to get 5 sets of results in order to get a suitable mean to form a bar graph with error bars. Now create a kite diagram, in order to identify any patterns shown. Wash your hands with soap and water and sanitize them after the experiment. Raw Results- Table to show the different plant and animal species found at the Rocky Shore along with the Substrate type. Group 1 (Myself and another class mate) Distance (+1-1 cm) Vegetation Percentage Cover Species Number (+1-1) Substrate Type 0m Algae
Littorina Obtusata 8 Rocky 5m -Prosobranchias -Littorina Obtusata -Littorina Saxatilis 10m 20 Rocks under water 15m 2 20m 10 25m 8% 35 30m 5% 25 35m 3% Rocky and dead rubble corals 40m 5 45m - Nerita chamaeleon 12 Rocky and pebbles 50m Nerita chamaeleon 4 To find out whether there was a diversity on the rocky shore or not, I used the Simpson''s Diversity Index: In this formula: n= the number of a particular type of species N= the total number of all the species D= diversity the sum of Simpson''s Diversity Index is a measure of diversity. In ecology, it is often used to quantify the biodiversity of a habitat.
It takes into account the number of species present, as well as the abundance of each species. With this index, O represents infinite diversity and 1, no diversity. That is, the bigger the value of D, the lower the diversity. Working out: I found out the total number of Littorina Obtusatas= 147 Littorina Saxatiliss= 6 Chameleon Nerites= 16 Prosobranchias= 2 Total number of species found= 171 Then I put the fgures above in the formula: 171 (170) Simpson''s Diversity Index = -0. 728 which suggests that there was no diversity found. Raw Results- Table to show the different plant and animal species along with the
Substrate type found at the Rocky Shore by my peers. Group 2: (ACFOR scale) Rocky under water 22% 17 2% 1% 6 Rocky and coral rubble 3 19 Rocky, pebbles and small rocks -Nerita chamaeleon 7 Rocky and boulders To find out whether there was diversity on the rocky shore or not, I used the Working out: Littorina Saxatiliss= 12 Nerita chamaeleon = 26 Prosobranchias= 3 Total number of species found= 188 / 188(187) Simpson''s Diversity Index = -0. 058, which suggests that there was no diversity found. Substrate type found at the Rocky Shore by another group of people. Group 3: 9 --prosobranchias 26 28 36% -Holothuria Atra 29
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