The Effect of Various Concentrations of Potassium Nitrate on the Growth of Algae (Nannochloropsis Oculata)

Elizabeth Struble, Mason Watts, Ellis Tontz, Kyntlie Wiles, Luberson Joseph


Algae are photosynthetic organisms that rely on nutrients, such as nitrogen and phosphorus, to multiply. If they receive an excess of nutrients, eutrophication occurs, which causes harmful algal blooms. However, algae is a great biofuel, and therefore can help to mitigate the negative effects of fossil fuels on the climate as well as possibly harness the algal blooms in a beneficial way. This leads to the question of what affects the growth of algae. We decided to test this question by observing the effect of various concentrations of potassium nitrate on the algae growth. We hypothesized that the higher concentration of potassium nitrate would cause the greatest growth. To test this, we added three different concentrations of potassium nitrate to three of the bottles and left one with no potassium nitrate added as our control group. A photobioreactor was created to leave the water bottles in for a week, and we used a hemocytometer to calculate the number of cells grown in each bottle at the beginning of the week and the end of the week. Our results found that the control group results in the greatest growth when compared to the treated group, disproving our hypothesis. However, within the experimental groups, the lower the concentrations of nitrate resulted in more growth. Further research should be conducted to see if these results can be corroborated as well as if this trend would continue.

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