Question

What change is seen in dissolved oxygen levels after 24 hrs?

• A. It will increase in the covered jar, but decrease in the uncovered jar.
• B. It will increase in the covered jar, but remain the same in the uncovered jar.
• C. It will decrease in the covered jar, but increase in the uncovered jar.
• D. It will increase in both jars.
• E. It will decrease in both jars.

Answer 1

The correct option is C It will decrease in the covered jar, but increase in the uncovered jar.

Dissolved oxygen levels are rarely constant and fluctuate with changes in season, temperature, and time of day.Time of day and temperature, in particular, have a profound effect on dissolved oxygen levels, partly because cold water tends to have more dissolved oxygen.increased levels of photosynthesis result in higher amounts of dissolved oxygen. The rate of photosynthesis increases with greater amounts of sunlight, resulting in elevated DO levels—independent of water temperature effects—during daylight hours. At night or when there is an absence of sunlight, there is a decrease in the photosynthetic activity while decomposition continues leading to fall in the dissolved oxygen levels independent of temperature factors.