Given the water samples we took and tested at Catalina, we have confirmed that the water is healthy, depth and pressure have little effect on the level of dissolved oxygen in the ocean, and there is hardly less oxygen as the pressure increases. Our results show that there is no major change in the level of dissolved oxygen at different depths, yet this is due to the lack of accuracy in our testing methods. The change in the amount of oxygen from the surface to 66 feet (our deepest dive) was only expected to be 0.04mg/l. This minimal change was not measurable by our testing kit, which tested for the level of dissolved oxygen for every three milligrams per liter. We are able to tell by the level of oxygen in Catalina, that the ecosystem is working, and there is no certain specie of animal which is particularly not thriving. In order to thoroughly understand our topic we would need to perform further experiments, understand the error, and discover the reason that the level of dissolved oxygen is different at different depths.

After solving various formulas for our hypothesis, we realized that we needed very accurate equipment to detect the change at depth. We were not able to use an electronic sensor which would have been able to measure to the level we need, because our hypothesis (click here to see our mathematical equations we used for our hypothesis) is much more detailed than our actual results. If we were able to use it, it would be beneficial for us to complete more experiments with a more accurate tester. We would also like to do the experiment at different times of the day and in different seasons. Another thing we could do, would be to heat up or cool down our samples to see how temperature would affect the oxygen saturation. It would also be good to be able to compare the oxygen level at greater depths. We were only able to test to depths less than 66 feet. We would like to test at greater depths to see if the pattern we found would continue. This would be very interesting to see whether or not the relationship between depth and oxygen level is linear.

For our experiment in Catalina, we used a Tetra test 02 kit to test the different levels of oxygen at different depths. As explained in our introduction, our method of testing was very vague, because it was made for testing in salt and fresh water aquariums. In the small confinement of an aquarium, the levels of oxygen vary more than in the great expanses of the ocean. This is why our method of testing was not appropriate for the types of an experiment we were completing. The kit we used is most frequently used to make sure animals have enough oxygen to survive in aquariums, and to see if animals are thriving in certain environments. Our samples were from water that was under a certain amount of pressure. When we brought it up to the surface the water was no longer at this pressure. Before we tested the water we had to wait for a safe time to exit the water, and take off all of our gear. In this fairly extensive period of time, it is possible that a small amount of oxygen could have escaped from the containers. This should not have a large effect, but depending on the accuracy of the testing method could be noticeable. Also, the time of day the samples are taken can influence the amount of oxygen that is found in the water. This is due to the fact that this bacteria and other organisms perform photosynthesis during the day, and produce oxygen. During the night they consume oxygen.

When computing our hypothesis, the pressure was the variable that changed, because we fixed the temperature variable at 15° C. This means our hypothesis proves that pressure really does affect the amount of oxygen in the ocean, although this was not shown by our results. Through much research, we have found that the oxygen level is greater at the surface, because warmer water is better able to absorb gases. This is due to the fact that the molecules move faster in warmer water. However, it can't hold as much oxygen because the molecules are moving faster and taking up more space. Colder water has a better capacity to absorb different gases, yet it doesn't have access to many gases. The water at the surface is warmer, due to the fact that sunlight is constantly in contact with the upper layers of sea water, and not the lower ones. The oxygen level changes because of bacteria attached to the bottom of the ocean, and living on aquatic plants, consume oxygen. Therefore, the amount of these organisms could influence the levels of oxygen in the water. Fish and decomposing material also has an affect on this.

Because of the results that we got we were not able to figure out very much about how the depth effects the level of dissolved oxygen. Through our extensive research we were able to figure out how they were related. Hopefully in the future other students will use our topic and perform more detailed experiments with our suggestions from this essay.

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