Investigation Species Richness Nicholas Mackenzie Scottish Candidate Number:

Investigation into the Relationship Between Water Pollution and Species Richness

 

Nicholas Mackenzie
Scottish Candidate Number: 060308047
Mearns Castle High School
Word Count: 3122
Contents Page

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Page 3 – Abstract

Page 4-5 – Introduction

Page 6-10 – Procedures

Page 11-13 – Results

Page 14-15 – Discussion

Page 16 – Appendix

Page 17 – Acknowledgements

Abstract

The aim of this investigation was to find out the effect of pollution in a freshwater river on species richness. Through this investigation, it has been possible to conclude that pollution in a freshwater river has a negative effect on species richness. This is because the results show that the average species richness score of five in the non-polluted area of water is higher than the average species richness score of 2 in the polluted area of water. The results also show that the non-polluted area had a higher ASPT score (6.6) is higher than that of the polluted area (5.8).

Introduction

Aim:
The aim of this investigation was to find out the effect of pollution in a freshwater river on species richness.

Hypothesis:
The hypothesis of this investigation was that river pollutants will have a negative effect on species richness.

Null Hypothesis:
The null hypothesis of this investigation was that river pollutants will have no effect on species richness.

Underlying Biology:

Factors Affecting Freshwater Pollution 
There are many different factors that can influence how strong the concentration of pollution is, such as the volume of water, the rate of removal of pollution and the speed of the water. There are other factors involved, such as the degradation and dispersal of chemicals. All these factors can determine the impact pollution can have on the organisms in rivers and lakes. 

Pollution of Freshwater by Fertilisers
Much of the pollution of freshwater rivers and lakes is caused by fertilisers. This happens when they are washed from the land into bodies of water by rain.This process is known as leaching, as the fertilisers pollute the water and cause the volume of nitrates and phosphates in the water to rise. This is known as eutrophication. This causes algae to develop and grow. The algae then rises to the top of the body of water, which stops the sunlight reaching other plants underneath the algae. As these plants are unable to carry out photosynthesis, they die. Bacteria are then able to decompose the dead plants, through respiring and using up oxygen. This causes the oxygen concentration in the water to decrease, resulting in the aquatic organisms being unable to respire and dying. 

Oil Pollution
Oil pollution can be caused by accidental damage or leakage of oil from ships and oil pipelines. Oils are made up of hydrocarbons, many of which are toxic and stop light penetration and gaseous exchange (i.e oxygen and carbon dioxide). Floating oil can even result in a decrease in the oxygen concentration in the water, as it inhibits the oxygen in the air from dissolving. In order to reduce oil pollution, oily waste water can be deposited at refineries instead of being emptied into the sea. Absorbent materials can also absorb oil and then be removed from the water and oil traps can be utilised to pick up oil from drainage water.

Pesticide Pollution
Most pesticides are released accidentally in a similar method to fertilisers. This can be dangerous for organisms in rivers and lakes, as pesticides are not specific and can seriously harm aquatic animals. Pesticides have many negative aspects, such as their non-specificity and persistence. They are also able to bio-accumulate. This involves toxins, such as pesticides, being built up in a food chain. Although the concentration at the beginning is very small, the concentration begins to accumulate from one organism to another. This results in the organism at the top of the food chain being affected most severely. As a result, pesticides have a direct effect on the aquatic life, as they can be toxic. It also has an indirect on other species, as the resulting death of fish and other organisms may result in a lack of food for other organisms. To combat these effects, many harmful pesticides such as DDT have been banned or restricted, especially those that biomagnify through food chains. Other non-chemical methods, such as biological control and crop rotation, can be used to reduce pesticide use.

Nutrient Pollution
A nutrient is a substance that helps develop the growth of a particular organism. Inorganic and organic nutrients in water can cause excessive growth which can cause certain issues, in different ways. Inorganic pollutants come from fertilisers on land and can result in stomach cancer and blue baby syndrome (methaemoglobinanaeimia) in humans and eutrophication in freshwater rivers and lakes. Organic pollutants can cause pathogens which spread diseases, such as typhoid and cholera. To minimise the impact of these nutrients, there are many different mechanisms. Screens are metal grills that trap large solids, such as plastic and paper. Activated sludge treatment involves using aerobic bacteria to digest organic matter.

Monitoring Water Pollution
There are many different methods of monitoring water pollution. Both physical and chemical tests for pollutants allow for precise, accurate, quantitative results but these results only display what is happening at that moment and cannot be used for a long-term assessment, as these values can vary. For example, the concentration of nitrites can be measured using a colorimeter, but this measurement will constantly change in the water, even if the measurement is taken from the same area.This will have to be taken into consideration for this investigation.

Rationale of Investigation
The reason behind this investigation is my desire to extend my knowledge on the impact that pollution has on freshwater organisms. Through my research, I have decided that I am going to measure the Biological Monitoring Working Party (BMWP) index for each organism and calculate the Average Score Per Taxa (ASPT). This will allow me to conclude on the impact pollution has on freshwater organisms, as the BMWP and ASPT allow for the assessment of pollution now and in the recent past.

Procedure

Pilot Study:

Aim:
The aim of this pilot study was to find out the effect of river pollutants on the abundance of freshwater shrimp.

Hypothesis:
The hypothesis of this pilot study is that river pollutants will have a negative effect on the abundance of freshwater shrimp.

Null Hypothesis:
The null hypothesis of this pilot study is that river pollutants will have no effect on the abundance of freshwater shrimp.

Variables:
The independent variable of this pilot study is the level of pollution.
The dependent variable of this pilot study is the abundance of freshwater shrimp.
The confounding variables of this pilot study are pH, temperature, velocity and oxygen concentration. As these confounding variables are not possible to control, it is important to monitor them by taking measurements of each of them.

Measurements/Observations
In this pilot study, I am going to be observing the number of freshwater shrimps that are present in polluted and non-polluted areas of a freshwater river. I am also going to be measuring the confounding variables in my pilot study.

Equipment List:

Tape measurer 
Impeller and hydroprop
Buckets
Dissolved oxygen meter
pH meter
Net
Identification key

Procedure

Lay out a measuring tape at least 10 metres long along the side of the non-polluted area of freshwater river.
Choose two random numbers between one and ten using a number generator. These numbers will be the coordinates, in metres, where the abiotic factors will be measured and the invertebrate sample will be taken.
Measure the pH, oxygen concentration, velocity and temperature at the coordinates chosen, using the appropriate equipment for each. The impeller and hydroprop is used to measure velocity, the pH meter is used to measure pH and the dissolved oxygen meter is used to measure oxygen concentration. Note these measurements.
At the location of the coordinates, place the net in the water approximately two inches above the ground, facing against the current of the river, and to the right of your feet.
For fifteen seconds, kick your feet forwards and backwards in the water, which will cause the freshwater invertebrates to fall into the net.
Place the net containing the invertebrates into a bucket half full of water.
Count the number of freshwater shrimp present in the bucket and note this number.
Place the invertebrates carefully back into the freshwater river. 
Repeat steps 2-8 twice and take an average for all abiotic measurements and the number of freshwater shrimp present.
Repeat full procedure for the area of the river which has been polluted.

Results:

Non-Polluted Area:

Average pH = 6.76
Average temperature = 7.6 degrees centigrade
Average velocity = 37.3 seconds
Average oxygen concentration = 12.43%
Average number of freshwater shrimp present = 20
Polluted Area:

Average pH = 7.76
Average temperature = 10.1 degrees centigrade
Average velocity = 35.3 seconds
Average oxygen concentration = 8.7%
Average number of freshwater shrimp present = 3

Conclusion:
To conclude, it was found that river pollutants had a negative effect on the abundance of freshwater shrimp. This is because the average number of freshwater shrimp found in the non-polluted area of the river was twenty, which is much greater than the average number of freshwater shrimp found in the polluted area. This value was three, which allowed me to form this conclusion.

Evaluation:
The results of this pilot study are accurate, as the pH was measured to two decimal places and the other confounding variables of this study were measured to one decimal place. The results can also be viewed as reliable are, as the confounding variables in this study had very small ranges for both the polluted and non-polluted areas of freshwater river. The largest pH range was 0.1, the largest temperature range was 0.7 degrees centigrade, the largest velocity range was forty four seconds and the largest oxygen concentration range was 1%. This means that the confounding variables of this study were constant, which increases the validity of this experiment. However, there have been several modifications from this pilot study for the investigation. The aim of the investigation was modified from investigating the effect of river pollutants on the abundance of freshwater shrimp to investigating the effect of pollution in a freshwater river species richness. This will allow the results to be analysed more thoroughly. In order to change the aim, the presence of different organisms present must be noted instead of the abundance of freshwater shrimp. The length of time kicking was also increased from fifteen seconds to one minute, as this will result in more organisms being caught in the net, which will improve the quality of the results. The organisms will also be transferred from the bucket to a white tray, in order for the freshwater invertebrates to be examined in more detail and to make sure that all the organisms are being accounted for.

Risk Assessment:
The site of this pilot study and investigation is a freshwater river.

Emergency Procedure:

Have an emergency float at the side to throw in if a person is drowning
Have first-aid kit present

Ethical Considerations:

As living organisms are being removed from their natural habitat (freshwater river) for a period of time, care must be taken to return the living organisms back into their natural habitat after they have been examined.
In order to cause the living organisms as little distress as possible, the fieldwork must be carried out swiftly and effectively.
To avoid contributing to soil erosion, walk on the paths next to the river when possible.

Independent Replicates:
In both the pilot study and the investigation, independent replicates have been included for both the polluted and non-polluted areas of the freshwater river. Each independent replicate was taken at random coordinates in both the polluted and non-polluted area to remove bias. This was important in improving the reliability of the experiment, as an average was also taken of all the measurements and observations.

Modified Procedure:

Lay out a measuring tape at least 10 metres long along the side of the non-polluted area of freshwater river.
Choose two random numbers between one and ten using a number generator. These numbers will be the coordinates, in metres, where the abiotic factors will be measured and the invertebrate sample will be taken.
Measure the pH, oxygen concentration, velocity and temperature at the coordinates chosen. Note these measurements.
At the location of the coordinates, place the net in the water approximately two inches above the ground, facing against the current of the river, and to the right of your feet.
For one minute, kick your feet forwards and backwards in the water, which will cause the freshwater invertebrates to fall into the net.
Place the net containing the invertebrates into a bucket half full of water. Then place the contents of the bucket into a white tray.
Using the identification key, identify the different organisms present and note their presence.
Place the invertebrates carefully back into the freshwater river. 
Repeat steps 2-8 twice and take an average for all abiotic measurements.
Repeat full procedure for the area of the river which has been polluted.

Results

In order to analyse the results fully, the Biological Monitoring Working Party Score (BMWP) was calculated for each sample. An average BMWP score was also calculated for the non-polluted and polluted area of the river. The BMWP is used to gauge the biological condition of rivers and streams, as each family of organism is assigned a score in relation to how sensitive they are to organic pollution. Scores are then added up to give the final BMWP score. The higher the score, the less tolerant the organism is to pollution. The Average Score Per Taxa  (ASPT) score was also calculated for each sample. This is considered a robust index, as this value is not influenced by sample size. The common name for each organism can be found in the Appendix.

Raw Data:

Non-Polluted Area:

Species present and their BMWP score
Sample one – Limnephilidae (6.9), Gammaridae (4.5), Baetidae (5.3), Heptagaenidae (9.8), Hydropsychidae (6.6)

Sample two – Heptagaenidae (9.8), Gammaridae (4.5), Limnephilidae (6.9), Planariidae (4.2), Hydropsychidae (6.6)

Sample three – Heptagaenidae (9.8), Gammaridae (4.5), Baetidae (5.3) Planariidae (4.2), Limnephilidae (6.9), Cordulegasteridae (8.6)

Sample four – Gammaridae (4.5), Heptagaenidae (9.8), Planariidae (4.2), Gyrinidae (7.8) Limnephilidae (6.9)

Sample five – Gammaridae (4.5), Baetidae (5.3), Heptagaenidae (9.8), Limnephilidae (6.9), Perlodidae (10.7)

Sample six – Gammaridae (4.5)Heptagaenidae (9.8), Limnephilidae (6.9), Gyrinidae (7.8), Baetidae (5.3)

Sample seven – Gammaridae (4.5), Heptagaenidae (9.8), Chironomidae (3.7), Limnephilidae (6.9), Hydropsychidae (6.6), Planariidae (4.2)

Sample eight-Gammaridae (4.5), Heptagaenidae (9.8), Hydropsychidae (6.6), Baetidae (5.3), Limnephilidae (6.9)

Average pH – 6.63 (to two decimal places)

Average temperature – 7 degrees centigrade

Average Velocity – 34 seconds (to nearest second)

Average oxygen concentration – 11.6% (to one decimal place)

Average species richness – 5 (to nearest whole number)

Average ASTP score – 6.6 (to one decimal place)

Polluted Area:

Species Present and their BMWP Score
Sample one – Gyrinidae (7.8), Planariidae (4.2)

Sample two – Baetidae (5.3), Sialidae (4.5), Hydrobiidae (3.9)

Sample three – Baetidae (5.3)

Sample four – Planariidae (4.2), Notonectidae (3.8)
Sample five – Limnephilidae (6.9)

Sample six – Gyrinidae (7.8)

Average pH – 7.69 (to two decimal places)

Average temperature – 10.6 degrees centigrade (to one decimal place)

Average velocity – 28 seconds (to nearest second)

Average oxygen concentration – 8.8% (to one decimal place)

Average species richness – 2 (to nearest whole number)

Average ASTP score – 5.8 (to one decimal place)

In these results, it is evident that as pollution increases, the ASTP score decreases. This is shown through the data, as the average ASTP score in the non-polluted area (6.6) is greater than the ASTP score in the polluted area (5.8). 

Discussion

Conclusion:
In conclusion, it was found that pollution in a freshwater river had a negative effect on species richness. This is because the results show that the average species richness score of five in the non-polluted area of water is higher than the average species richness score of two in the polluted area of water.

Evaluation of Procedures:
For this investigation, the equipment used was effective in measuring the confounding variables. All equipment allowed readings to at least one decimal place, which allowed for accurate measurements of the confounding variables to be taken. As it was not possible to control the confounding variables of this experiment, the pH, temperature, velocity and oxygen concentration was measured at each sample and an overall average was taken for both the polluted and non-polluted areas of the freshwater river. This was to allow these abiotic factors to be monitored. Due to the weather causing the river to rise above knee depth, it was only possible to take six samples of the polluted water. This is still a sufficient number of samples to account for the margin of error. However, if it were possible to perform this experiment again, I would ensure that a minimum of eight samples were taken to increase the validity of this investigation. Due to the nature of this experiment, it was also not possible to create a positive and negative control. This is because there was no possible way to manipulate my experiment into producing specific results. One negative aspect of this experiment is that the abundance of each species was not recorded. This information could have been used to calculate species diversity, which would have strengthened these results and allowed a conclusion involving both species diversity and species richness to be reached. The modifications made to both the aim of the investigation and the procedure, through evaluation of the pilot study, both improved the experiment design and increased the validity of these results. The use of independent replicates being taken at random coordinates was also a very good aspect of the experiment, as it allowed bias to be removed from the investigation.

Evaluation of Results:
The results obtained through this experiment are appropriate, as they allow a conclusion to be drawn that is related to species richness in a freshwater river and the impact pollution has on this. It has been recognised that the confounding variables may have had an impact on the results of the investigation. This is because there was a slight contrast in the measurements of these variables from the non-polluted area to the polluted area. However, as there was very little range for each confounding variable for both areas of the freshwater river and the contrast is small, it can be assumed that there will have been very little impact on the investigation. As a control could not be created for this experiment, the results obtained are not as valid as they could have been. However, the use of eight independent samples in the non-polluted area of freshwater and six samples in the polluted area of freshwater make this investigation valid, as this is a sufficient amount of samples to account for the margin of error. The use of revised BMWP scores from Staffordshire University also helps ensure the accuracy of the results, as this allowed for a more accurate ASTP score to be calculated. As Staffordshire University is a reliable source, this also makes these results more reliable. This investigation has allowed me to develop my knowledge on the impact pollution has on species richness in a freshwater river. Through examining the results, I am now planning to investigate how species diversity is affected by pollution in a freshwater river and draw a conclusion about the effect pollution has on biodiversity.

Appendix

Common Name Of Organisms
Limnephilidae – Cased Caddis Fly

Gammaridae – Freshwater Shrimp

Baetidae – Swimming Mayfly

Heptagaenidae – Flat Mayfly

Hydropsychidae – Brown Caseless Caddis Fly

Planariidae – Flatworm

Cordulegasteridae – Dragonfly

Perlodidae – Stonefly

Gyrinidae – Whirligig Beetle

Chironomidae – True Fly

Sialidae – Alderfly

Notonectidae – Backswimmer

Hydrobiidae – Mud Snail

Acknowledgements

1.) Article Title: BBC Bitesize – GCSE Biology – Water pollution and deforestation – Revision 2
Website title: Bbc.co.uk
URL: https://www.bbc.co.uk/education/guides/zyvwxnb/revision/2

2.)Article title: Table of Revised BMWP Scores
Website title: Cies.staffs.ac.uk
URL: http://www.cies.staffs.ac.uk/bmwptabl.htm
Publisher: Ray Martin 
Date: 21 April 2004

3.)Article Title:GCE Environmental Studies
Website title: Filestore.aqa.org.uk
URL: http://filestore.aqa.org.uk/subjects/AQA-2440-W-TRB-OGTNU3.PDF
Publisher: Dr Michael Cresswell, Director General.
Date: 2009

Finally, I would like to acknowledge the support that I received from the Mearns Castle High School Biology department. The guidance from Mrs Dempster throughout the whole investigation is greatly appreciated. I would also like to thank the staff at FSC Kindrogan for assisting me during my procedure and providing me with the appropriate equipment for my investigation. 

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