Goal: To determine changes over time in a “raw” aquarium ecosystem as variables, both biotic and abiotic, are gradually added. Also, to create an experimental situation where all aspects of the scientific method can be practiced.

Hypothesis:

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Materials: aquarium tank, tap water, thermometer, floating thermometer, pH paper, hydrometer, gravel, turbidity chart, water quality test kits (or individual test kits for nitrate, phosphates, dissolved oxygen), algae (Elodea/Anacharis), and feeder goldfish and/or guppies.

Procedure:

1. Getting Ready - Tank Set-up:

• Clean the tank with water only. Do Not use soap or detergent (only scouring pads, brushes, etc.)

2. Fill the tank, determine the number of gallons = ________

3. Let sit for 24 hours to test for leaks. Report any leakage & there location to the teacher for repair.

4. WEEK O - Fill your aquarium with tap water and complete the following 9 tests. Agree with other groups upon a depth in the tank from which all samples will be taken. Make sure that you remove the water sample from the agreed upon location (sample depth) in the tank. These measurements will be your baseline abiotic water quality data.

• air temperature
• water temperature
• pH
• specific gravity
• nitrate
• phosphate
• dissolved oxygen
• color
• turbidity
• Follow teacher directions for testing protocol and record your results in the data table worksheet.
• Record observations on the Observation Sheet.
• Take a picture of your tank with the digital camera.

5. WEEK 1 - Abiotic Water Quality Data & Addition of Gravel

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet.
• Rinse gravel 2-3 times with water and add to tank. Gravel should cover the bottom surface of the tank completely to a height of 4-5 cm. The gravel will displace tank water. You may need to remove some water from the tank before adding gravel. Do not discard this water. After the addition of gravel to the tank this water return the tank to its original fill level (under the plastic rim).

6. WEEK 2 - Addition of Pond Inoculum

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet.
• On your microscope observation worksheet, record the date of inoculation. In addition, record the date the pond inoculate was collected, the location of the pond, and all results of the 9 water tests performed on the original pond sample.
• Using microscopes, view several drops of tank water to determine if any living organisms are present. Record the results in the microscope observation worksheet. This is your baseline biotic (living) data.
• Next, add 10 ml. of pond inoculate per gallon of water to your tank. For example; if you have a 10 gallon tank, you should add 100 ml of inoculate.
• Add tap water to your tank to bring the water level back up to the fill level. Make sure the water that is being used is not directly from the tap. All water which is to be used to refill tanks should set for at least 3-4 days before being added to aquarium.
• Microscope observations should be recorded weekly, noting date, magnification, size of any organisms, and an accurate drawing of organisms including a written description.

7. WEEK 3 - Addition of Simple plants

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet.
• Conduct microscope observations on your aquarium water noting date, magnification, size of any organisms, and make an accurate drawing of organisms including a written description.
• If you are working with a 10 gallon tank remove 5 bundles of Elodea or Anacharis and place on a paper towel (if your tank is smaller, use only 1-2 bundles). Check each stalk for any attached snails. If you find snails, remove and place them in the designated aquarium. Find the mass of your plants and record on Observation Sheet.
• Place the plants in your aquarium. Each plant stock should be individually secured into the gravel. Try to evenly space the plants throughout the aquarium. Draw a diagram of the location of each plant on the Observation Sheet.
• Add tap water to your tank to bring the water level back up to the fill level. Make sure the water that is being used is not directly from the tap. All water which is to be used to refill tanks should set for at least 3-4 days before being added to aquarium.

8. WEEK 4 - Simple Invertebrates Added

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet.
• Conduct microscope observations on your aquarium water noting date, magnification, size of any organisms, and make an accurate drawing of organisms including a written description.
• Re-secure any plants which have floated to the top of the tank into the gravel. Try to replace the plants in their original location (see Observation Sheet for plant locations). Count the number of plants and record this number on your data table. Draw a diagram of the location of each plant on the Observation Sheet.
• Add 2 snails per 10 gallon tank (or 1 snail for smaller tanks). On your tank diagram note the location of the tank where you placed these snails.
• Add tap water to your tank to bring the water level back up to the fill level. Make sure the water that is being used is not directly from the tap. All water which is to be used to refill tanks should set for at least 3-4 days before being added to aquarium.

9. WEEK 5 - Addition of Simple Fish

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet
• Conduct microscope observations on your aquarium water noting date, magnification, size of any organisms, and make an accurate drawing of organisms including a written description.
• Re-secure any plants which have floated to the top of the tank into the gravel. Try to replace the plants in their original location (see Observation Sheet for plant locations). Count the number of plants and record this number on your data table. Draw a diagram of the location of each plant on the Observation Sheet.
• Count and record the number of snails in your tank. Note the location of the snails on your tank diagram. Make sure to look carefully at the sides of the tanks for "little" snails. If "little" snails are presents they most likely came from the plants and the snails were either too small or missed the day the plants were being added.
• Add gold fish (or cheapest available fish from aquarium supply store). Gold fish should be 2-4 cm. long. For small tanks (5 gallons or less) add 3 or 5 fish. For larger tanks, add 10 or 12 fish.
• Add tap water to your tank to bring the water level back up to the fill level. Make sure the water that is being used is not directly from the tap. All water which is to be used to refill tanks should set for at least 3-4 days before being added to aquarium.

10. WEEK 6 THROUGH 10 - Continued Abiotic/Biotic Observations

• Take a picture of your tank with the digital camera.
• Conduct the 9 required tests and record in your data table. Make sure water is removed from the tank at the agreed upon sample depth.
• Record observations of tank on Observation Sheet
• Conduct microscope observations on your aquarium water noting date, magnification, size of any organisms, and make an accurate drawing of organisms including a written description.
• Re-secure any plants which have floated to the top of the tank into the gravel. Try to replace the plants in their original location (see Observation Sheet for plant locations). Count the number of plants and record this number on your data table. Draw a diagram of the location of each plant on the Observation Sheet.
• Count and record the number of snails in your tank. Note the location of the snails on your tank diagram. Make sure to look carefully at the sides of the tanks for "little" snails. These snails came from the plants and were either too small or missed when the plants were being added.
• Count the number of living fish in your tank. Record this number on your data table. Remove any dead fish from the tank.
• During this period make sure you keep a close eye on your tank and note any changes in tank appearance or in fish behavior.
• Add tap water to your tank to bring the water level back up to the fill level. Make sure the water that is being used is not directly from the tap. All water which is to be used to refill tanks should set for at least 3-4 days before being added to aquarium.

11. At some point your class should determine when to stop the experiment. When the experiment is halted, analyze your data (i.e. use your data to determine when to add new variables, find out why test results changed, why dissolved oxygen is important, etc.) and use this to establish a new aquarium. With the lessons learned, the new aquarium will hopefully become an even more viable ecosystem.