Got Pollution? Nitrogen and Phosphorus Pollutants Affect Dissolved Oxygen in Pond Water

Kelsie Hoelscher, Mallory Dixon, Cody Duttry, Justin Agan


A natural occurrence that frequently occurs in bodies of water around the world is eutrophication, which is when large amounts of nutrients (most commonly phosphates) accumulate in the water. This stimulates an increase in the growth of plant-life and algae. Unfortunately, as the algae die, their decomposing bodies release bodily wastes which diminishes the presence of oxygen within a body of water. Due to a lack of oxygen, the fish population is reduced. It is important to consider the effects of eutrophication because it affects the ecosystem in a number of ways, including organism populations and agricultural problems. The most common question is how phosphates and nitrates have impacted eutrophication. Although previous research has mentioned the presence of phosphorus and nitrogen in the water and its effect on the surroundings (Hoefnagels, 2015; Daniel et al., 2009), it has failed to acknowledge how a range of various substances influence eutrophication. We want to know whether or not certain chemicals and substances affect the process of eutrophication. In order to proceed where the previous research left off, we included fertilizer, which is a good source of phosphorus as well as nitrogen, in addition to ammonia (only a nitrogen source) and dish soap (mainly a phosphorus source); we combined each of these substances with yeast into their own respective test tube and conducted a timed experiment intended to measure the dissolved oxygen concentration. We found that the fertilizer sample with added yeast had a greater rate of change than the other pollutants. The yeast acted as a decomposer and may have decomposed more algae when fertilizer is present in the water. The fertilizer may cause a higher level of algae, leading to more dead algae for the yeast to decompose, which lowers the dissolved oxygen level. Ultimately, we hope our research can help determine which solutions enhance or reduce the dissolved oxygen in order to prevent the decline of the fish population.

Keywords:  eutrophication, dissolved oxygen, phosphates, nitrates, population decline

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