The document summarizes background information on various organisms and substances that could be included in an experimental eco-tank, including their biological classifications and relevant characteristics. It discusses fish (platy fish), shrimp, snails, algae, and aquatic plants (Elodea, Vallisneria). For each, it covers anatomy, diet, life cycle, predators, and environmental tolerances. The goal is to investigate the interactions between organisms and how substances affect the environment within the controlled eco-tank.

1. THE ECO-TANK Yr 11 Biology Aqueous Systems Assignment Extended Experimental Investigation Donna Burns OTHER MEMBERS IN GROUP: Ime Britz Laura Stack Kelsey Hutchings

2. TABLE OF CONTENTS Aim Hypothesis Terminology Used in Assignment Background Information Context of Assignment Risk Assessments Method Apparatus Results Discussion Conclusion Bibliography Acknowledgements Appendices

3. AIM To investigate the life within a controlled Eco-Tank and come to an understanding of how various organisms and substances effect the environment within the biological filter. Also to recognise the extent to which the experiment is valid, and obtain the ability to apply knowledge gained to real life situations. Return to Table of Contents

4. HYPOTHESIS During the experiment, expected outcomes are as follows: All organisms within the tank will only be able to survive according to their tolerance levels. Organic substances within the tank will fluctuate and vary according to the behavior and presence of organisms within the tank. A food web will form in the tank in relation to the organisms present, with the primary consumer being decomposers. Outside variables (e.g. weather) will have an influence on the life within the tank. The tank will only be able to support a certain number of organisms before the environment becomes unstable and will cease to be a functional biological filter. Return to Table of Contents

5. TERMINOLOGY USED IN ASSIGNMENT Organism: living matter, capable of independent existence, which can grow and reproduce. Food Web: all the possible feeding relations in an ecosystem . Decomposers: organism which utilises dead organisms or waste matter for its nutrient requirements, breaking down the complex organic molecules and releasing simple molecules back into the environment for reuse by producers. Primary Producers: autotrophic organism, forming the base of all food chains. Autotrophic: plants which produce their own food. Return to Table of Contents

6. BACKGROUND INFORMATION Fish Shrimp Snails Algae Plants Elodea Vallisneria Importance of Plants Photosynthesis Oxygen Sure Start pH Water Hardness Biological Filter Eco System Nitrogen Cycle Sustainability Law of Tolerance Healthy Tank Return to Table of Contents

7. FISH BACKGROUND INFORMATION The southern platy fish is a species of freshwater fish in the Poecilidae family. Platy’s are closely related to the green swordtail, and can interbreed with it. It is native to an area of North and Central America stretching from Mexico to northern Belize. The southern platy fish grows to a maximum overall length of 6.0. It’s sexual dimorphism is slight, and the male's caudal fin is more pointed. Wild varieties are drab in coloration, lacking the distinctive dark lateral lines common to many Xiphophorus species. Return to Table of Contents Source: 5 & 6 Animalia Kingdom: Cyprinodontiformes Order: Xiphophorus Genus: Poeciliidae Family: Actinopterygii Class: Chordata Division: CLASSIFICATION

8. FISH cont. BACKGROUND INFORMATION Return to Table of Contents Source: 6

9. FISH cont. BACKGROUND INFORMATION Platys prefer slow-moving waters of canals, ditches, and warm springs. They are omnivores, with a diet consisting of plants and small crustaceans insects and worms. Platys are easy to keep and well suited to a community aquarium. They prefer water with a neutral pH, a water hardness of 9.0–19.0, and a temperature range of 18–25 °C . In captivity, Platys reach maturity in 3–4 months and breed readily, with the females giving birth to about 40–50 young each time. Source: 5 & 6 Return to Table of Contents

10. SHRIMP BACKGROUND INFORMATION Shrimp are small animals that live on the floor of oceans and lakes. There are over 2,000 different species of shrimp worldwide. Anatomy: The invertebrates range from a small fraction of an inch to 9 inches long. These crustaceans have a thin, smooth, hard, and almost transparent exoskeleton. Shrimp vary widely in colour, with tropical varieties often possessing bright colours. Shrimp have 5 pairs of jointed walking legs on the thorax, 5 pairs of swimming legs (swimmerets) and 3 pairs of maxillae (feeding appendages) on the abdomen. The body, legs, swimmerets, and other appendages are segmented. Shrimp have two pairs of segmented sensory antennae, a tail fan, and compound eyes. Source: 3 & 4 Return to Table of Contents Animalia Kingdom: Decapoda; Natania Order: Crustacea Class: Athropoda Division: CLASSIFICATION

11. SHRIMP cont. BACKGROUND INFORMATION Diet : Shrimp are omnivores; they eat plants and small animals. The unusual pistol shrimp kills or stuns its prey by making a very loud sound with a huge claw with a moveable, snapping appendage. Life Cycle : Female shrimp lay over a thousand eggs, which are attached to her swimming legs. The shrimp emerge as tiny, floating organisms, a component of zooplankton. After growing, they sink to the bottom, where they live. As shrimp grow, they often malt. (losing old shells and growing new ones). Predators : Shrimp are eaten by many animals, including many fish, many birds, octopi, squid, cuttlefish and people. Source: 3 Return to Table of Contents

12. SNAILS BACKGROUND INFORMATION The name snail applies to most members of the mollusca class Gastropoda that have coiled shells. Snails are herbivores which are found in freshwater, marine and terrestrial environments. While most people are familiar with only terrestrial snails, the majority of snails are not terrestrial. Snails with lungs belong to the group Pulmonata, while those with gills form a paraphyletic group. Snails live all over the world, from the arctic to tropics. They come in all sorts of varieties. Many are edible while some are poisonous, some bite and some give birth to live young. Snails are often classified by the environment which they live in. For example, salt-water, fresh-water, or on land. This is not a biological classification, but one of convenience. Source: 7 & 10 Return to Table of Contents Animalia Kingdom: Gastropoda Class: Mollusca Phylum: CLASSIFICATION

13. SNAILS BACKGROUND INFORMATION Many fresh water snails actually have lungs, and must come to the surface to breath, and many fresh water snails descended from snails that have adapted to life on the land, and have moved back to water. Some of these have re-developed gills, while others have not. Humans have an interest in fresh water snails, because various species can carry the schistosomiasis parasite which is a major health concern in areas of the world where indoor plumbing has not yet become common. We also like to use some species of fresh water snails for our aquariums. Source: 8 & 9 Return to Table of Contents

14. ALGAE BACKGROUND INFORMATION Algae are photosynthetic organisms that occur in most habitats, ranging from marine and freshwater to desert sands and from hot boiling springs to snow and ice. They vary from small, single-celled forms to complex multi-cellular forms, such as the giant kelps of the eastern Pacific. These grow to more than 60 meters in length and form dense marine forests. Source: 22, 23, 24 Return to Table of Contents Plantae in Part Kingdom: Chlorophyta Charophyta Division: CLASSIFICATION

15. ALGAE cont. BACKGROUND INFORMATION Algae exhibit a wide range of reproductive strategies, from simple, asexual cell division to complex forms of sexual reproduction. Algae are important as primary producers of organic matter at the base of the food chain. They also provide oxygen for other aquatic life. Algae may contribute to mass mortality of other organisms, in cases of algal blooms, but they also contribute to economic well- being in the form of food, medicine and other products. In tropical regions, coralline algae can be as important as corals in the formation of reefs. Source: 22, 25 Return to Table of Contents

16. PLANTS – ELODEA BACKGROUND INFORMATION Elodea is a genus of aquatic plants often called the Water weeds. It is native to North America and it is widely used as aquarium vegetation. Due to the introduction of the plant in some countries, it has created significant problems in waterways and is often considered a noxious weed. The plant is often referred to as the American waterweed or Anacharis. It is an attractive plant and often used effectively in aquariums. Source: 17 Return to Table of Contents Plantae Kingdom: Alismatales Order: Elodea Genus: Hydrocharitaceae Family: Liliopsida Class: Magnoliphyta Division: CLASSIFICATION

17. PLANTS – VALLISNERIA BACKGROUND INFORMATION Vallisneria is also a genus of aquatic plant, commonly called eelgrass or tape grass. The genus has 6-10 species that are widely distributed, but do not grow in cold regions. The plant is an under water species, which spreads by runners and sometimes forms tall underwater meadows. It’s leaves arise in clusters from their roots, which have rounded tips and definite raised veins. Single white female flowers grow to the water surface on very long stalks, with its fruit having a banana-like capsule containing many seeds. Source: 18 Return to Table of Contents Plantae Kingdom: Alismatales Order: Vallisneria Genus: Hydrocharitaceae Family: Liliopsida Class: Magnoliphyta Division: CLASSIFICATION

18. PLANTS – VALLISNERIA cont. BACKGROUND INFORMATION Various strains of Vallisneria are commonly kept in tropical and subtropical aquaria. These include dwarf varieties and varieties with leaves around 15 to 20 cm in length long. With few exceptions, the commonly traded Vallisneria are tolerant and adaptable. While they do best under bright illumination they will do well under moderate lighting. Once settled in, they multiply readily through the production of daughter plants at the end of runners. Once they have established their own roots, these daughter plants can be cut away and transplanted if necessary. Vallisneria will accept neutral to alkaline water conditions and are also among the few commonly traded aquarium plants that tolerate brackish water. Source: 18 Return to Table of Contents

19. PLANTS BACKGROUND INFORMATION Elodea has a fairly complex structure that is good for egg deposition by fishes such as garfish and hardyheads (freshwater fish that attach eggs to vegetation). The plant is very good for still or slow moving water, which has a high surface area and produces lots of oxygen during the day. Valissnaria is different in that it is a poorer egg deposition substrate, although the rare Queensland lungfish (Neoceratodus Forsteri) does lay its eggs among its roots. This water plant is better suited to moderate and fast flowing water. Source: Tibbetts Return to Table of Contents

20. IMPORTANCE OF PLANTS BACKGROUND INFORMATION Plants are extremely important within the tank, as they are one of the primary producers within the environment. As well as providing food, they also photosynthesise, which turns the carbon dioxide produced by the organisms in the tank into the oxygen which is necessary for the tank’s survival. Return to Table of Contents

21. 6H2O + 6CO2 C6H12O6 + 6O2 “ Process whereby radiant energy (visible spectrum) is converted to chemical energy of glucose; requires, carbon dioxide, water and a suitable temperature. Occurs in green plants, algae and some bacteria.” (Huxley & Walter, 2002, p582) PHOTOSYNTHESIS BACKGROUND INFORMATION Return to Table of Contents

22. OXYGEN BACKGROUND INFORMATION The relationship between temperature and oxygen is significant. As the temperature of the water increases, the dissolved oxygen level decreases. This relationship exists because oxygen cannot dissolve in water of high temperatures. As can be seen on the graph Solubility of Oxygen in Water as Temperature Increases . Return to Table of Contents

23. OXYGEN: SOLUBILITY IN WATER BACKGROUND INFORMATION Source: 12 Return to Table of Contents Mg/L 15 10 5 Solubility of Oxygen in Water as Temperature Increases

24. OXYGEN: WATER AGITATION BACKGROUND INFORMATION One way to increase oxygen levels is water agitation. This is a process where the surface of the water is disturbed, increasing the water’s surface area to volume ratio, thus increasing the water’s ability to intake oxygen. Return to Table of Contents

25. SURE START BACKGROUND INFORMATION Return to Table of Contents Sure start is used to condition the water in aquariums and stop stress and disease occurring within the tank. Water containing Chlorine and Chloramine is harmful and highly toxic to fish and aquatic life. Sure Start removes toxic substances and neutralises harmful metals to prepare for the introduction of fish. Sure Start is an aid in maintaining fish’s fluid and electrolyte balance, and therefore reducing stress. Source: 20

26. pH BACKGROUND INFORMATION pH is a measure of the activity of hydrogen ions (H+) in a solution and, therefore, its acidity or alkalinity. 7 is neutral, anything below is acid, and anything above is alkaline. Left: some common pH levels Source: 16 Return to Table of Contents 13.5 Household lye 12.5 Bleach 11.5 Household ammonia 9.0 – 10.0 Hand soap 8.0 Sea water 7.34 – 7.45 Blood 6.5 – 7.4 Healthy human saliva 7.0 Pure water (neutral) 6.5 Milk 4.5-5.7 Human Saliva in Cancer Patients 5.5 Tea 5.0 Coffee <5.0 Acid Rain 4.5 Beer 3.5 Orange or apple juice 2.9 Vinegar 2.5 Cola 2.4 Lemon juice 2.0 Gastric acid -0.5 Battery acid -3.6 – 1.0 Acid mine runoff pH Substance

27. WATER HARDNESS BACKGROUND INFORMATION Hardness is a measurement of the concentration of divalent metal ions such as calcium, magnesium, iron, zinc etc, usually acquired as rainwater percolates through rock. Most water consists mainly of calcium and magnesium salts, with trace amounts of other metals. General hardness is primarily the measure of calcium and magnesium ions in the water. Other ions can contribute to General Hardness, but their effects are usually insignificant and the other ions are difficult to measure. General Hardness will not directly affect pH although &quot;hard&quot; water is generally alkaline due to some interaction between the two kinds of hardness, general and carbonate. Source: 15 & Tibbetts Return to Table of Contents

28. ECO-SYSTEMS BACKGROUND INFORMATION “ Ecosystems are dynamic interactions between plants, animals, and microorganisms and their environment working together as a functional unit. Ecosystems will fail if they do not remain in balance. No community can carry more organisms than its food, water, and shelter can accommodate. Food and territory are often balanced by natural phenomena such as fire, disease, and the number of predators. Each organism has its own niche, or role, to play.” Source: 11 Return to Table of Contents

29. BIOLOGICAL FILTER BACKGROUND INFORMATION Biological filtration involves bacteria and other micro-organisms (and to a lesser extent plants and some fungi) converting fishes' waste into less toxic substances. Fish excrete waste (urine and faeces) into their aquarium water constantly as they make use of the food they eat. This waste, if not removed, will become toxic to the fish. A biological filter will convert toxic ammonia (from fishes' waste, excess food, decaying or dying plant mater, and dead fish) into Nitrite, and toxic Nitrite into Nitrate. Nitrate is relatively harmless, however, if it is not removed from the tank through regular water changes, Nitrate can cause kidney, liver and eye problems for fish, as well as suppress their appetite and prevent their gills from absorbing oxygen from the water. Nitrate will also contribute to algae growth. Biological filtration occurs as the water passes over any surface that the bacteria processing the waste can grow on. Source: 1 Return to Table of Contents

30. BIOLOGICAL FILTER cont. BACKGROUND INFORMATION Biological filtration is established during a process called ‘cycling’. Even the highest quality biological filters cannot process fish waste until they have properly cycled. Plants can use some nitrogenous waste as fertilizer, though they will only be able to process this as they photosynthesize during the day. The concentration of nitrogenous waste used by plants will be so minimal as to make no significant difference in water quality. At night, however, plants respire just as animals do, and will be producing nitrogenous waste. Cycling occurs when a culture of bacteria is formed, which digests ammonia and turning it into Nitrite. The filter then produces bacteria that digests Nitrite, and turns it into relatively harmless Nitrate. However, Nitrate will cause fish to lose their appetite, allowing for algae growth. Regular small water changes keep tanks in best condition. Source: 1 & 2 Return to Table of Contents

31. BIOLOGICAL FILTER cont… BACKGROUND INFORMATION Cycling a tank with many fish will produce a lot more waste, which will be stressful on fish, resulting in higher fatality rate and greater susceptibility to disease. Cycling with a large number of fish will increase water problems incurred during the cycling process. Cycling with a lot of fish can contribute to a unpleasant odour coming from the tank. The cycling process usually takes four to eight weeks. Source: 2 Return to Table of Contents

32. NITROGEN CYCLE BACKGROUND INFORMATION Source: 13 Return to Table of Contents

33. NITROGEN CYCLE cont. BACKGROUND INFORMATION As mentioned while discussing the biological filter , the nitrogen cycle inside a fresh water ecosystem converts toxic nitrogenous substances into harmless nitrates which is then utilised again by the organisms within the environment. As outlined in the figure Nitrogen Cycle (Biological Filtration), the cycle begins with the waste and dead matter in the tank converting into ammonia. This turns into nitrite, then into nitrate, which is absorbed by the plants within the tank, and is passed back to the heterotrophic organisms in the tank, where the cycle begins again. Without aeration or sufficient filtration, these toxic substances build up in the tank, which is fatal for organisms in the tank. Return to Table of Contents

34. NITROGEN CYCLE cont. BACKGROUND INFORMATION The most efficient way to control the nitrogen levels in a fresh water aquarium is to do frequent and small water changes. As can be seen in the Nitrogen Cycle graph to the left, the nitrogen level within the tank continues to rise until a water change is conducted. Source: 2 & 14 Return to Table of Contents

35. SUSTAINABILITY BACKGROUND INFORMATION “ The ability to provide for the needs of the world's current population without damaging the ability of future generations to provide for themselves. When a process is sustainable, it can be carried out over and over without negative environmental effects or impossibly high costs to anyone involved.” Return to Table of Contents Source: 21

36. LAW OF TOLERANCE BACKGROUND INFORMATION Studies of environmental influences on plants and animals showed that not only too little of a substance or condition limit the presence or success of an organism, but also too much. “ For each organism there exists a specific tolerance range for any essential environmental factor below or above which the organism’s activity is adversely affected” Eugene Odum “ Death verges on the limits of toleration. Existence of a species would be jeopardised if it is too frequently exposed to limits of tolerance.” S. Charles Kendeigh In 1913 a development of the Law of Tolerance stated that a species has a range of tolerance or requirements with a minimum on one hand and a maximum on the other. Source: 19 & Tibbetts Return to Table of Contents

37. HEALTHY TANK? BACKGROUND INFORMATION To constitute a healthy tank and to reduce the stress of the organisms within the tank, levels within the tank must stay within the acceptable range of tolerance. These expected levels for the eco-tank are as follows. Temperature: 18 – 25 degrees Celsius Nitrate: 0 – 0.5ppm Nitrate: 0 – 0.5ppm Ammonia: 0 – 0.5ppm Oxygen: 5 – 20 mg/L Carbon Dioxide: 0 – 20 mg/L Water Hardness: 5 – 15 mg/L pH: 6.5 – 7.5 Return to Table of Contents

38. CONTEXT OF ASSIGNMENT Studying aquariums illustrates the basic requirements for life in the food chain as well as the underlying importance of water quality. The Eco-Tank has no filter system or pump and as a consequence the fresh water organisms in the tank are dependant upon autotrophic organisms for both oxygen and food. Prepare a Scientific Report outlining the results obtained and research the life within an aquarium over three to four months. Evaluate the results to understand how the conclusions drawn are important to everyday life. Return to Table of Contents

39. WATER TESTS: RISK ASSESMENTS See appendices for the risk assessments and material safety data sheets of the following water tests and chemicals: Appendix 1: Dissolved Oxygen Appendix 2: Water Hardness Appendix 3: Carbon Dioxide Appendix 4: Ammonia Appendix 5: Nitrate Appendix 6: Nitrite Appendix 7: Sure Start Return to Table of Contents

40. METHOD In a small aquarium, cover the base of the tank with a few cm’s of clean pebbles and potting mix. Fill tank with water, leaving a few cm’s empty at the top. Attach a thermometer to the side of the tank. Add two kinds of fresh water plants to the tank. Add recommended amount of sure start. Let tank stabilise for a few days. Add three small platy fish and several small fresh water snails. Complete a small water change (10%) 2-3 times a week, or a slightly greater water change if necessary. Return to Table of Contents

41. METHOD cont. Begin keeping a scientific journal recording growth of organisms, water tests completed, temperature of tank as well as any observations and analysis. After a few weeks, add a medium sized (2-3cm) shrimp and observe and disruptions or changes to the tank life. Remove snails which have reproduced. Remove shrimp and once again observe changes in behaviour and tank levels. Replace any fish which died or were eaten. Return to Table of Contents

42. APPARATUS Small Aquarium Fish tank pebbles Potting mix Fish, Shrimp, Snails and water plants Materials and chemicals for the following water tests: Oxygen Carbon Dioxide pH Nitrate Nitrite Ammonia Water Hardness Thermometer Beaker for water changes Sure Start Return to Table of Contents

43. RESULTS Photograph Journal Entries Graphs & Charts Food Web in Eco-Tank Return to Table of Contents

44. PHOTOGRAPH RESULTS Return to Table of Contents

45. JOURNAL ENTRIES RESULTS Return to Table of Contents 10. 23-2 11. 28-2 12. 1-3 13. 3-3 14. 6-3 15. 9-3 16. 14-3 17. 15-3 18. 17-3 1. 3-2 2. 6-2 3. 7-2 4. 8-2 5. 9-2 6. 15-2 7. 17-2 8. 20-2 9. 22-2 28. 7-4 29. 26-4 30. 28-4 31. 3-5 32. 4-5 33. 10-5 34. 12-5 35. 18-5 19. 20-3 20. 22-3 21. 23-3 22. 28-3 23. 29-3 24. 30-3 25. 31-3 26. 5-4 27. 6-4

46. GRAPHS & CHARTS RESULTS Oxygen & Temperature Oxygen & Organisms Oxygen & Carbon Dioxide Water Hardness, Oxygen & Carbon Dioxide Ammonia, Nitrite & Nitrate Return to Table of Contents

47. OXYGEN & TEMPERATURE RESULTS Go to Source Data No data collected in holidays Link to Discussion Return to Table of Contents

48. OXYGEN & ORGANISMS RESULTS Large Snail Reproduction Added Shrimp Remove Shrimp All fish eaten Add 2 fish Coller Weather Decline in amount of Algae No data collected in holidays Link to Discussion Return to Table of Contents

49. OXYGEN & CARBON DIOXIDE RESULTS Go to Source Data Link to Discussion Return to Table of Contents No data collected in holidays

50. WATER HARDNESS, 02 & CO2 RESULTS Go to Source Data Link to Discussion Return to Table of Contents No data collected in holidays

51. NITROGENOUS SUBSTANCES RESULTS Go to Source Data Link to Discussion Return to Table of Contents No data collected in holidays

52. FOOD WEB IN ECO-TANK DISCUSSION SHRIMP FISH PLANTS SNAILS DECOMPOSERS ALGAE Return to Table of Contents

53. DISCUSSION Patterns and Trends Oxygen & Temperature Oxygen & Organisms Water Hardness & Oxygen Oxygen & Carbon Dioxide Nitrogenous Substances Water Changes & Nitrate Return to Table of Contents

54. OXYGEN & TEMPERATURE PATTERNS & TRENDS As seen in the graph oxygen and temperature , the link between the two variables is consistent with the research in the background information . As the temperature in the tank increases, the level of the dissolved oxygen in the tank decreases. For example, in the portion of the graph shown to the right, as the temperature (blue) decreased, the dissolved oxygen (pink) increased. Taken from graph: Oxygen & Temperature Return to Table of Contents

55. OXYGEN & ORGANISMS PATTERNS & TRENDS On the graph Oxygen and Organisms , it is shown clearly that as the number of oxygen using organisms increase in the tank, the oxygen level goes down. Also, as the number of oxygen dependant organisms reduce in the tank, the oxygen level increases. Return to Table of Contents

56. WATER HARDNESS & OXYGEN PATTERNS & TRENDS As can be seen in the graph water hardness, oxygen and carbon dioxide , there is a close relationship between water hardness and oxygen. The two substances closely follow each other. As hardness increases, so does the oxygen, and as oxygen decreases, so does the hardness. Return to Table of Contents

57. OXYGEN & CARBON DIOXIDE PATTERNS & TRENDS The pattern between carbon dioxide and oxygen , as can be seen in the graph, exists with both levels going in opposite directions. While the oxygen is low, the carbon dioxide levels are rising, and the same applies for the other way around. Taken from graph: Oxygen & Carbon Dioxide Return to Table of Contents

58. NITROGENOUS SUBSTANCES PATTERNS & TRENDS When looking at the graph, Ammonia, Nitrite and Nitrate , a cause and effect chain takes place. According to research in the background information , after an increase of ammonia, this should turn into nitrite, and then nitrate. The results from the eco-tank support this to a certain degree, however, the first substance to peak is nitrite, rather than ammonia, which is then followed by nitrate, then ammonia. Return to Table of Contents

59. CONCLUSION Oxygen & Temperature Oxygen & Organisms Water Hardness & Oxygen Oxygen & Carbon Dioxide Nitrogenous Substances Case Studies Errors Inaccuracy Limitations & Improvements Support Hypothesis Return to Table of Contents

60. OXYGEN & TEMPERATURE CONCLUSION As mentioned in the background information , the link between temperature and oxygen is due to the ability of oxygen to dissolve in water of different temperatures. When the temperature of the water increases, the dissolved oxygen in the water decreases because oxygen cannot dissolve in water with high temperatures. The findings of eco-tank support this knowledge, in that the oxygen in the tank corresponds with the changing temperature. Return to Table of Contents

61. OXYGEN & ORGANISMS CONCLUSION When looking at the relationship between the amount of organisms in the tank and oxygen levels, it can be concluded the number of oxygen using animals in the tank determines the amount of oxygen present. When there is a sustainable amount of organisms in the tank, the oxygen levels can be kept stable by the plants which are photosynthesising. However, where there are too many oxygen consuming organisms, the plants cannot keep up with the demand for oxygen. As can bee seen in the graph , when the shrimp was added, the oxygen level dramatically decreased, and when the shrimp was removed, the oxygen level increased once more. This increase was followed by a sudden decrease, due to the introduction of two more fish to replace the ones the shrimp ate. Return to Table of Contents

62. WATER HARDNESS & OXYGEN CONCLUSION The pattern between these two substances is quite surprising. Hardness is measurement of the concentration of metals in water. When this level is high, the oxygen level in the tank is expected to decline. However, this was not the case in the eco-tank. As the level of hardness in the tank increased, so too did the oxygen. This anomaly was unable to be explained. Return to Table of Contents

63. OXYGEN & CARBON DIOXIDE CONCLUSION In regard to the relationship between oxygen and carbon dioxide, the link between them occurs because of the interaction between the plants and breathing organisms. Fish, snails and shrimp all require oxygen to breathe, and all expel carbon dioxide. Plants and algae do the opposite and harvest the carbon dioxide through photosynthesis and replace oxygen back into the water, as shown in the diagram. Plants & Algae Fish, Shrimp & Snails O 2 CO 2 Cycle of Oxygen and Carbon Dioxide within the eco-tank. Return to Table of Contents

64. OXYGEN & CARBON DIOXIDE cont. CONCLUSION Due to this process, the trend between the two organic substances can be explained. If the fish produce more carbon dioxide than the plants can convert into oxygen, the carbon dioxide levels in the tank will increase, and the oxygen level will decrease. However, if there is an excess of plants in the tank which are producing oxygen, and not as many breathing organisms to keep up with the supply, the oxygen will increase in relation to the carbon dioxide levels. Return to Table of Contents

65. NITROGENOUS SUBSTANCES CONCLUSION In reference to Ammonia, Nitrate and Nitrite, the flow of these nitrogenous substances follow on from each other. The accepted course of these substances (Ammonia – Nitrite – Nitrate) is similar to that in the eco-tank. However, with the lack of recorded information, as well as due to the unavailability of resources, this can not necessarily be finalised. It is possible that the level of ammonia in the tank peaked before the test could be conducted, which would then comply with the general flow of the three substances. The school holidays also posed an inconvenience as the patterns of the substances could not be observed during this time. Return to Table of Contents

66. APPLICATION: CASE STUDY CONCLUSION With the growing local industry of fish and seafood farming, many issues arise relating to the availability of water, condition of water, conservation of natural aqueous systems, efficiency and sustainability. Return to Table of Contents Binger Weir Farm: Local Red Claw, Shrimp & Feeder Fish Farm

67. CASE STUDY cont. CONCLUSION The growing market is primarily made up of shrimp, brim, red claw and feeder fish. To address the first concern, which is availability, condition and source of water, considerations should be made to the location of the farm. If the farm is in proximity to any agriculture farms which would produce a lot of runoff water, it would be possible, and environmentally friendly, to collect this water for the use of the farming enterprise. This water would contain high levels of nutrients, minerals and nitrogenous substances which after a natural treatment, like the filter demonstrated in this assignment, could be beneficial to the farm. Return to Table of Contents

68. CASE STUDY cont. CONCLUSION By collecting the runoff water, the amount of contaminated water reaching other farms and ultimately oceans is reduced. If the water reached the ocean, this would have on impact on the sustainability of the local marine life, and in turn affect the local fishing industry. Farming fish and other fresh water aquiculture products also has many advantages regarding the efficiency and profitability of the industry, which also conserves the natural supply in our local reefs and fresh water systems. When using a controlled method of aquiculture farming, it is possible to boost the production of the farm by controlling the cycle of the fish and crustaceans and sort the organisms to ensure consistency of the product. Consistency and reliability of product is something which cannot always be ensured when dealing with natural sources. Farming of these organisms also reduces the amount of possible waste product, which occurs during collection of fish in natural supplies. Return to Table of Contents

69. CASE STUDY: CONTEXT PICTURE CONCLUSION Binger Weir Farm: Pond containing Red Claw, Shrimp & Feeder Fish Also grown in ponds: Vallisneria and Water Lilies

70. CASE STUDY cont… CONCLUSION A method of farming which dramatically increases the production of a product is known as intensive farming. This system manipulates the regular growth rates of organisms to meet the demand for produce. Techniques such as enriching food supplies and reducing growing space allow for rapid growth and increased profit. There are however, elements of ethics and acceptance of society which make intensive farming difficult. Different views on how animals should be treated before being processed are present. Intensive farming is often rejected by society. However, much of society is unaware of farming methods, or simply decide not to be concerned about the consequences of intensive farming. Return to Table of Contents

71. ERRORS: WHAT WENT WRONG? CONCLUSION Shortly after the fresh water shrimp was added to the eco-tank, all three existing fish disappeared. As this process was never witnessed, only the assumption that the shrimp ate the fish could be made. However, knowledge of shrimp behaviour supports this assumption and justifies our conclusion on the matter. This finding was inconvenient, although, it is consistent with findings in natural environments. Return to Table of Contents

72. INACCURACY CONCLUSION Inaccuracy is a large issue when dealing with investigations with only one subject. In the eco-tank experiment, it is quite possible that the results gained are not accurate or in accordance with a natural fresh water environment. Water tests also allow room for inaccuracy. It was not easy to gain accurate and consistent results from the water tests, as each member of the group testing the water had slightly different interpretations of the test. Return to Table of Contents

73. LIMITATIONS & POSSIBLE IMPROVEMENTS CONCLUSION Due to the Easter holidays, over a two week period in April, no water tests or changes could take place. Biology classes were not always on the same day, so long periods of time without access to the tank make recording accurate data difficult. Variations in weather caused fluctuations in results, however this would also be the case in a natural environment. Limitations in supplies for water test made it difficult to keep constant records of substances in water. The experiment was constricted to only one tank from which to collect data. If conducting the investigation again, numerous tanks would be used, or exchange of data with other groups using similar methods would take place. Also, if replicating the assignment, greater care would be taken to test water on a regular basis for each appropriate test. Return to Table of Contents

74. SUPPORT HYPOTHESIS CONCLUSION Findings of this experiment did support the original hypothesis stated. As discussed, Organic substances within the tank fluctuated due to the behavior and presence of organisms within the tank. Outside variables such as weather had an impact on the levels within the tank. The main level effected by weather being oxygen. A food web formed in the tank, which changed according to different organisms in the tank. Generally, all the levels in the tank stayed within the estimated law of tolerance, so this hypothesis was not able to be fully supported. Due to the careful supervision of the levels within the tank, the eco-tank was never stressed to the extent whereby it could no longer support organisms in the tank. Therefore, this hypothesis could not be supported either. Return to Table of Contents

75. BIBLIOGRAPHY World Wide Web: Source 1 & 2 http:// www.firsttankguide.net/filters.php (29/5/06) http:// www.firsttankguide.net/cycle.php (29/5/06) The above sources assisted in my research into Biological filters. The website provided information in a way which was easy to follow, relevant to the topic being addressed and concise. Source 3 & 4 http://www.enchantedlearning.com/subjects/invertebrates/crustacean/Shrimp.shtml (30/05/06) http://en.wikipedia.org/wiki/Shrimp (30/05/06) Sources listed provided a labeled diagram, pictures, classification and information regarding shrimp. Source 5 & 6 http:// en.wikipedia.org/wiki/Xiphophorus_maculatus (30/05/06) http://www.pbs.org/wgbh/nova/teachers/activities/images/3003_fish_2.gif (30/05/06) The wikipedia encyclopedia was very useful for classifying fish as well as providing general background information and photographs, while the second reference provided a labeled diagram of a basic fish. Return to Table of Contents

76. BIBLIOGRAPHY cont. World Wide Web: Source 7, 8, 9 & 10 http://www.everything2.com/index.pl?node=snail (30/5/06) http://www.drhelm.com/aquarium/snails.html (30/5/06) http://grimwade.biochem.unimelb.edu.au/cone/cone1.html (30/5/06) http://en.wikipedia.org/wiki/Snails (30/5/06) These four sites were used in conjunction to gain information, classification and photographs of snails and the mollusca’s. Source 11 http://library.thinkquest.org/11353/ecosystems.htm (30/5/06) This source provided a quote containing the definition of ‘ecosystem’ and general information regarding environments. Source 12 http://cee.citadel.edu/Civl312/Oxygen%20Solubility%20Table.htm (30/5/06) Source provided data concerning solubility of oxygen in water as temperature increases. Source 13 & 14 http://upload.wikimedia.org/wikipedia/en/thumb/e/e9/Aquarium_Nitrogen_Cycle.png/300px-Aquarium_Nitrogen_Cycle.png (30/5/06) http://www.algone.com/images/cycle3.gif (30/5/06) Obtained images of the nitrogen cycle from sources listed. Return to Table of Contents

77. BIBLIOGRAPHY cont. World Wide Web: Source 15 http://www.fishdoc.co.uk/water/hardness.htm (6/6/06) Acquired information about Water hardness. Source 16 http://en.wikipedia.org/wiki/PH (6/6/06) Researched for the definition of pH Source 17 & 18 http://en.wikipedia.org/wiki/Elodea (6/6/06) http://en.wikipedia.org/wiki/Vallisneria (6/6/06) Gained information, classification and pictures of both species of water plants, Elodea and Vallisneria. Source 19 http://www.nrm.calpoly.edu/envm.files/306/Section01.3.DOC (6/6/06) Information and quotes regarding laws of tolerance. Source 20 http://www.aristopet.com.au/Library/Downloads/Downloadable%20pdf%20files/Product%20Info%20Sheets/AM140%20Sure%20Start%20INFO.pdf (11/6/06) Sight for Sure Start. Obtained pictures and information. Return to Table of Contents

78. BIBLIOGRAPHY cont. Source 21: http://www.google.com/search?hl=en&lr=&q=define%3A+sustainability (11/6/06) Defined: sustainability. Source 22, 23, 24 & 25: http://www.nmnh.si.edu/botany/projects/algae/ http://en.wikipedia.org/wiki/Chlorophyta http:// www.math.utah.edu /~korevaar/fractals/gallery/algae.jpg http://www.hawaii.edu/reefalgae/invasive_algae/chloro/clad_field_good_small.jpg (11/6/06) Information, classification and pictures about Algae. Text: Source 1: Huxley & Walter, An Australian Biology Perspective, 2002, Oxford University Press, Melbourne. Return to Table of Contents

79. ACKNOWLEDGEMENTS Dr Ian Tibbetts, (PHD), Marine Biologist. Dr Tibbetts, who is a specialist researcher into the Queensland Garfish, assisted in the research of water hardness and pH levels, fresh water aquarium plants and the law of tolerance. DPI Excursion. Mr Campbell, Tour Guide on Excursion to the Bundaberg BPI Facility Bingera Weir Farm Return to Table of Contents

80. APPENDICES Appendix 1: Dissolved Oxygen Appendix 2: Water Hardness Appendix 3: Carbon Dioxide Appendix 4: Ammonia Appendix 5: Nitrate Test Solution 1 & 2 Appendix 6: Nitrite Test Solution Appendix 7: Sure Start Return to Table of Contents

81. THANKYOU DONNA BURNS MR JOHNSTONE 11c