Let It Gro! How Nitrogen, Phosphorus, and Potassium Concentration Affects Growth in Nannochloropsis oculata Algae

Abstract

Autotrophs like Nannochloropsis oculata algae, make their own food and energy, so they are a great option for harnessing biomass which allows for production of biofuel. We wanted to know what fertilizers would most efficiently grow Nannochloropsis oculata algae; therefore allowing for more economic production of biofuels. Based on this background information, we hypothesized that the algae in the photobioreactors that contain fertilizer with higher percentages of nitrogen, phosphorus, and potassium will increase in number. We tested our hypothesis by creating eight photobioreactors; four of the photobioreactors were our experimental group with the fertilizer added, and the other four photobioreactors were the control group with no ‘treatment’. In order to understand the difference between the control group and the experimental group, we compared cell density and dry weight between the two groups. After conducting the experiment and analyzing our gathered data, we found that our hypothesis was rejected. Contrary to our hypothesis, we discovered that the photobioreactors that contained the added fertilizer did not increase the growth of the algae as much as we had anticipated. We believe the reason the fertilizer did not grow the algae as much as we had expected, this could be because the amount of fertilizer we added was too much for the container and amount of algae used. So, instead of growing the algae like we thought the fertilizer would, it decreased the growth as well as killed some of the cells in the algae.