Hypothesis

After looking at the population density and the development in the area for each water sample, we thought that each water sample would have a different amount of dissolved oxygen. 

Dissolved Oxygen Hypothesis

Since Tommy Pond is surrounded by two acres of trees and forested area, we thought that there would be a moderately high amount of dissolved oxygen. Since the water is fresh water, the water is more soluble and it can hold more dissolved oxygen. Trees that let off oxygen would benefit the pond because it could absorb into the pond. However, since there is no stream or current occurring, wind or turbulence would not be a main source for dissolved oxygen. Plants growing at the bottom of the pond would release oxygen into the water, however since the pond is only .4 acres, there is not a significant source of oxygen coming from plants. The temperature of the water at Tommy Pond was also slightly higher then the beach, and  higher temperatures hold less amounts of dissolved oxygen.

Since Sandy Hook Beach has a high population density, we believed the water there would be polluted from boats and humans swimming in the water. Gas exhaust from the boats could cause a large amount of CO2 to accumulate in the water, lowering the amount of dissolved oxygen available. There are also not a lot of plants growing at the bottom of the ocean near the shore, so there would be little oxygen entering the water through plants. Also, high amounts of salinity lowers the amount of solubility in water. Since Sandy Hook Beach contains salt water, the amount of dissolved oxygen is lowered because it cannot dissolve in the water. However, wind near the shore is always very strong, so a lot of wind could enter the ocean through the waves crashing on the shore. This would result in extremely low amounts of dissolved oxygen at Sandy Hook Beach.

The Delaware and Raritan Canal is close to Rutgers University in Princeton, New Jersey where there are a lot large buildings. With the population of Rutgers university reaching about 50,000 students alone, there is a high population density. These factors could cause a lot of pollution to enter the canal from both littering and pollution from the buildings and people living there. High amounts of pollution prevents a large amount of plant life to grow in the water, resulting in a low amount of photosynthesis as well. Since there is a small amount of plants able to take in the carbon dioxide put in the water from pollution and release oxygen to put back into the water, we expected low amounts of dissolved oxygen to be in the canal water.


Amount of Sunlight/ Screen Hypothesis
Adding on to our hypothesis for the different amounts of dissolved oxygen in the water samples, our class also tested the amount of dissolved oxygen after being subjected to different amounts of sunlight. We hypothesized that as more screens were added on, and less sunlight was allowed into the water samples, the amount of dissolved oxygen would lessen. This is because without sunlight, organisms cannot preform photosynthesis, which releases oxygen into the water. Also, organisms take in the available oxygen through cellular respiration, lowering the amount of dissolved oxygen even further.