How Fertilizer (10 N-P-K) Affects the Oxygen Production of Algae

Shelby Orth, Kamry Lafayette, xavier jace kelley, Samuel Carlton Little, Eric Bates


Water quality all across the United States is threatened by the fertilizers and other chemicals used by farmers. Much of what is used does not get utilized by the plants and runs off into nearby water sources. The runoff leads to eutrophication, an excessive amount of nutrients and lower level of dissolved oxygen (DO). Oklahoma is a good place to show this as it is a highly agricultural state. So, we want to find out how the fertilizer affects the rate of photosynthesis of the algae within the samples. Water from Lake Hefner and 10 N-P-K fertilizer was utilized to test the DO level. We predict that the DO level will decrease when fertilizer is present. Five trials measuring the DO of 50mL of water from Lake Hefner and five trials with 5mL of 0.17g/L fertilizer and 45mL of water were taken. Our results show that without the addition of fertilizer the DO level was slightly higher than with the fertilizer. This supports our hypothesis and prediction since the DO was affected by the fertilizer even though the difference is small. This shows that an abundance of fertilizer run off can negatively affect the production of oxygen from algae. There have been several other studies done that support this. In the future different sample sizes, different concentrations of fertilizer, and longer trials could be completed to test this further.

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