Equipment We Shall Use…
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Ranging Poles: These are long poles with red and white “rings” at various lengths. NB The positions at which each red/white ring starts are the same on every ranging pole.
We shall start at 0meters and place a ranging pole into the ground, the other one shall be placed further inland where the ground first peaks. The angle of elevation will then be recorded using clinometers. The next pole shall be placed into the ground at the closest lowest point, and the angle of depression measured. We shall do this until we reach 200meters.
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Clinometers: These are used for measuring angles of depression and angles of elevation. We shall use the clinometers in cohersion with the ranging poles. To measure the angle of elevation we shall hold the clinometers at a specific point of one of the ranging poles then measure the angle that is shown when it is pointed at the same point on the other ranging pole. The angle of depression is measured in the same way only the clinometers will be pointed down instead of pointed upwards.
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Quadrates: These are used to calculate the percentage cover of a various species of plants in a specific area. They will be place down at every 10meter intervals. We shall observe the types of plants in the quadrate and the abundance of them. Giving them a value of Abundant, Common, Frequent or Occasional.
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Soil Sample: At every 10meter intervals we shall use a small troul and place some soil into a small bag. We will then tie the bag and mark the site number.
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pH recording: At every 10meter intervals we shall record the pH of the soil. We shall do this by using an analogue pH meter.
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Compass: We must perform our experiment in a straight line at an angle of 180 degrees from the waters edge. To make sure that we stay on a direct heading we must use a compass to show the heading.
Method In The Field…
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We shall place a tape down at the waters edge and also place the first Ranging Pole down at this point.
- This is now called site 1.
- Using the pH meter we shall record the pH of the sand and note down the result.
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We shall also take a soil sample from site 1, by using the trouel and placing into the bag, marking the bag as site 1 and tying it.
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We shall then place down the quadrate. We shall observe the plants can be found at this site and the percentage abundance (Giving a value of either A, C, F or O)
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We shall then check the compass to find the direction in which the next site should be situatited. Then using the measure we shall indicate site 2, 10meters from site one.
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We shall then repeat steps 3 to 6 until we reach site number 21.
Dune Profile Method…
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At site 1 we will place the first Ranging Pole into the ground so that the end of the metal point is just below the sand.
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We will place the next Ranging Pole into the ground where the ground peaks; making sure it is in the correct direction. Make sure that we have pushed the Ranging Pole into the ground so that the end of the metal point is just below the sand. We must not forget to note the distance.
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Next we shall place the clinometer next to the part on the first Ranging Pole where the red/white finishes and the white/red starts.
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Now we shall hold the clinometer so that it points to the corresponding point on the second Ranging Pole and measure the angle.
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We will then Place the next Ranging Pole at the next lowest point and record the angle given.
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Then we need to repeat the above procedure for about 200 meters recording all the distances and the angles.
NB
A positive number indicates that there is an increase in height, the angle of elevation. While a negative number indicates that there is a decrease in height, the angle of depression.
Example Of Dune Profile Results…
Back In The Labs…
Once we have gained all the results that we need from the beach we will take our samples to the lab. At the lab we will perform several experiments on each sample. We will conduct several experiments on each sample to discover the percentage of water each sample contains. We will also calculate the percentage of humus contained within each sample. Also we will check the pH of each sample-just to make sure the results previously gained are correct.
Percentage Of Water…
- Weigh an empty dish.
- Place the sand from site 1 into the dish.
- Weigh the sample from site 1 in a dish.
- Note the initial weight.
- Place into an oven and leave for several days.
- Take the sample out and re-weigh.
- Use the below formula to deduce the percentage of water contained within the sample.
- Repeat these steps for all the samples obtained.
% Water = 100 Initial weight – Final weight
Initial weight
The pH…
- Take a small sample of dry sand from site 1. i.e. The sand that has come out of the oven after the above calculation has been done.
- Place this small sample into a test tube.
- Add to the sample distilled water (has a pH of 7, which is neutral)
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Also add the this mixture “Some Barium Sulphate BUT CHECK WHAT IT WAS”
- Add to the mixture some Universal Indicator solution.
- Allow the solution to settle and then compare the colour of the solution with a chart.
- Note the reading obtained.
- Repeat the above steps for each site.
Percentage Of Humus…
- Take the sand from sample one and place into a copper dish.
- Weigh the sand and the dish together and record the reading gained.
- Place the copper dish onto a tripod and place a Bunsen burner under the tripod.
- Hold another Bunsen burner so that the flame is touching the sand.
- This will cause any humus contained within the sample to be burnt.
- Once there is no more combustion allow the dish to cool then reweigh.
- We will then use this result to calculate the percentage humus the sample contained, by using the equation given below.
- Repeat the above steps for all the samples.
% Humus = 100 (the difference in mass)
The initial mass
The Results…
Once we have gained all the results we shall place them into several different tables. Like the one previously shown and the ones shown below. We shall also plot a kite graph that will show the dune profile and also will show the abundance of particular types of plants and the different types of plants. To be able to analyse the data further we will perform Spearman’s Ranks Correlation Coefficient. (Will be explained in more detail later)
The Kite Graph…
To draw the kite graph we will simply follow the steps below…
- Take a piece of A2 graph paper and turn it so that you are working landscape.
- Along the horizontal axis draw a scale of distance so that all the points at which the angle of elevation/depression were taken can be plotted.
- Next take a ruler. Using the ruler draw a straight vertical line from the point where the first angle was recorded.
- Now use a protractor to work out the correct angle and mark a point on the vertical line where this angle crosses.
- Join this mark to the one before.
- Repeat the above steps until there are no more readings.
- The dune profile is now complete.
- Next along the vertical axis write the names of the different species of plants that were observed.
- Using the scale: 4 squares high = Abundant
3 squares high = Common
2 squares high = Frequent
1 square high = Occasional
Plot in the correct places the results obtained for each plant. If there is a plant at one site but not the next then find the point in between the two sites and join this point with the previous result so a “diamond” forms.
NB
Don’t forget to join the points together if plants are found in site next to one another, with straight lines.
Spearman’s Rank Correlation Coefficient…
- Draw a scatter graph to see if the two variables that you want to correlate are related.
- Devise a Null-Hypothesis about the two variables.
- Produce a table like the one below: -
- Place values into the table for variable A and also for variable B.
- Next Rank the values of A, the greatest value being 1.
- Rank the values of variable B next.
- For each pair of values work out the difference in rankings and place into the column titled D.
- Simple multiply D by itself for the final column.
- Using the equation shown below calculate the correlation coefficient, then cross-reference with a chart.
NB
If the level of significance is above 95% we reject our null-hypothesis and accept our other hypothesis. The table gives the level of significance.
Rs = 1 - 6 x ( D2)
N3 – N
Sample Results Tables…