Course Work Sample: The Effects of Dissolved Oxygen on Fish Growth

Dissolved oxygen is oxygen that is trapped in a fluid, such as water. Since virtually every living organism requires oxygen to survive, it is a necessary component of water systems such as streams, lakes, and rivers in Dissolved oxygen is oxygen that is trapped in a fluid, such as water. Since virtually every living organism requires oxygen to survive, it is a necessary component of water systems such as streams, lakes, and rivers to support aquatic life. The dissolved oxygen is measured in units of ppmor parts per million. Examine the data in Table 4 showing the amount of dissolved oxygen present, and the number of fish observed in the body of water the sample was taken from; finally, answer the questions below.

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Questions

What patterns do you observe based on the information in Table 4?

It is evident that the as the dissolved oxygen in water increases the more the number of fish increases. It can be stated that the amount of dissolved oxygen in fish is directly proportional to the number of fish in water.

Develop a hypothesis relating to the amount of dissolved oxygen measured in the water sample and the number of fish observed in the body of water.

Ho: Number of fish in water is not affected by the amount of dissolved oxygen in water

H1: Number of fish is affected by the amount of dissolved oxygen in water

What would your experimental approach be to test this hypothesis?

The set up will involve an experimental set-up and a control set-up. The control set-p will have 0ppm dissolved oxygen. On the other hand, the experimental setup will have the amount of dissolved oxygen varied to determine how it affects the number of fish.

What would be the independent and dependent variables?

In an experiment, quantities are always varied to establish the response of other quantities. These values that respond to change are known as variables. A dependent variable is a variable that is not changed during the experimental process, but the value depends on other values. On the other hand, the independent variable is a value in an experiment which is not affected by other changes in other values. In this experiment, the dependent variable is the number of fish since it is affected by the amount of dissolved oxygen in the water. The changes in dissolved oxygen directly affect the number of fish in the water.

What would be your control?

In this experiment, a control experiment will be water with 0 amount of dissolved oxygen. This control experiment will help to isolate the results as far as the number of fish and dissolved oxygen is concerned.

What type of graph would be appropriate for this data set? Why?

A line graph will be the most appropriate in this case. A line graph has always been identified as the best graph for tracking changes. In this study, the main aspect being studied is the changes in the number of fish as influenced by the amount of dissolved oxygen. In addition, line graphs can be used to compare changes in two variables. In this study, a line graph can be used to compare changes between the dependent and independent variable.

Graph the data from Table 1: Water Quality vs. Fish Population table (found at the beginning of this experiment).

Interpret the data from the graph made in Question 7.

At the point where dissolved oxygen is 0, water cannot support aquatic life. At this point, no fish can survive in the water. As some oxygen increases, the number of fish in the water increases. However, the number of fish will increase up to a point where the optimum amount of fish can be accommodated in a water body. In addition, hyperoxia, which is a state of the high amount of dissolved oxygen in water also affects the number of fish supported. Excess oxygen can also be detrimental to aquatic life (Mallya, 2007).

References

Mallya, Y. J. (2007). The effects of dissolved oxygen on fish growth in aquacullture. Retrieved from http://www.unuftp.is/static/fellows/document/yovita07prf.pdf