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Biology LibreTexts

3.4: Graphing Data

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  • Examine the graph below

    a. As temperature increases, what happens to the solubility of oxygen in water?

    b. Water in a particular stream varies from 8 - 13 mg/liter. What temperature range does this reflect?



    Fish require oxygen to live. As water passes through gills, dissolved oxygen (DO) is transferred to blood. Dissolved oxygen in water is affected by:

    Photosynthesis: During light hours, aquatic plants produce oxygen. Mixing: Waves and waterfalls aerate water and increase oxygen concentration.

    Decomposition: As organic material decays, bacteria consume oxygen. Salinity: As water becomes more salty, its ability to hold oxygen decreases.

    Examine the graph below:

    a. At which temperature is dissolved oxygen highest?


    b. A trout requires more DO when the water temperature is 24oC (75oF) as compared to when the water temperature is 4oC. (to support an increase in metabolic activities). How do the DO levels compare at these two temperatures?

    c. A power plant discharges warm water into a river. Why would this have a detrimental effect on fish that live in the river? Be specific in your answer and relate it to this lab.


    High levels of CO2 have been implicated in global warming and as a causative factor in mass extinctions.

    a. Construct a line graph of the 1970–2018 data by decade from 1970 and ending with to 2010.

    b. State a conclusion as to the change in CO2 levels over time.