Below there are some Aquarium Project sample questions. You may find these questions useful when discussing various topics with your class or you may want students to include answers to these questions in their lab write-ups.
Table of Contents
 DISSOLVED OXYGEN |
 PHOSPHATES |
 NITRATES |
 TEMPERATURE |
Photosynthesis in plants requires carbon dioxide (CO2), water (H2O) and light to produce oxygen (O2) and energy. In aquatic plants, the oxygen produced can be measured as dissolved oxygen. At night there is no light, therefore, a plant cannot produce oxygen. However, it does require oxygen for metabolistic respiration
- If a plant is using but not producing oxygen at night would you expect the D.O. level in your tank to increase or decrease at night?
- When would you expect to measure the lowest lever of D.O. in your tank?
- What might this mean for other organisms, such as fish, in your tank?
- Would you expect to find a higher dissolved oxygen content in a body of water in the winter or in the summer?
- List three factors that could influence the dissolved oxygen concentration of a body of water
- Do you think it would be wise to stock a pond with gamefish if it had a dissolved oxygen content of 3ppm? Why or why not? What is an ideal concentration of dissolved oxygen?
Use the following links to help you answer the above questions.
Nitrates are a fertilizer that helps plants grow. A common source for nitrates is the waste products of animals and bacteria.
- Thinking about photosynthesis and D.O., how can high levels of nitrates contribute to a poor environment for aquatic organisms?
- How might a "population explosion" of animals, such as snails or fish, cause death for these same animals?
- Why is nitrate so efficient at leaching into groundwater?
- What are nitrogen fixing bacteria?
- Why are farms often seen as a major source of nitrate contamination?
- What is an algal bloom, what is it caused by and how can it affect life in a body of water?
Use the following links to help you answer the above questions.
Similar to nitrates, phosphates are a fertilizer that helps plants grow. A common source for phosphates is in the waste products of animals and bacteria. Phosphates are also added to water at treatment facilities to help remove heavy metals.
- How might a "population explosion" of animals, such as snails or fish, cause death for these same animals?
- If you were in charge of a pond and noticed that there was below average growth of algae and green plants in the pond, why would you test for phosphate concentration?
- How could a population of small mouth bass be indirectly affected by an influx of phosphate into the area in which they live?
- Why is it necessary to put restrictions on phosphate in laundry detergents?
- What effects would a concentration of 3mg/L have on a lake? 25mg/L?
Use the following links to help you answer the above questions.
Dissolved oxygen, nitrates, pH, and phosphate measurements can change with a change in temperature. As water warms, it will hold less dissolved oxygen, but more nitrates, phosphates and hydrogen atoms (lower pH).
- Thinking about what water molecules are doing when temperature increases, Why does dissolved oxygen decrease and nitrates, phosphates, and hydrogen atoms increase?
- What effect might warmer water have on oxygen-dependent living organisms?
