How Increased Levels of Nitrogen Affect Dissolved O₂ Content Over Time in Three Different Water Samples

Abstract

Because we needed to know how sewage pollution affects dissolved O2 concentration in natural water sources, we researched the effects of adding nitrogen to water. Through our research, we discovered that sewage releasesnitrogen and algae strives on nitrogen (Smith et al, 1999). We know that algae consume CO2 and releases O2, so we designed an experiment where we could add various amounts of nitrogen and measure the changes in dissolved O2over time. We hypothesized that the N given off by the sewage would cause the algae population to increasequickly and dramatically, which would initially result in an increase in dissolved O2; however, as the algae overpopulated, they would use up their resources and die out, which would be reflected by a decrease in dissolvedO2. In order to test natural water, we selected samples from the Dolese Outflow, Pond, and Creek. Using an experimental group with added N and a control group with only distilled water added for volume, we took 4dissolved O2 readings at 1 week intervals for 4 weeks and graphed our findings.