Dissolved Oxygen and Temperature Lab 16 A

 

The shape of the standard curve is nearly linear. If the average is taken and a standard fit line is placed, it would be linear. The line, however, is linear in the wrong fashion. Based on previous knowledge, the dissolved oxygen levels should decline as temperature increases, as shown in the following graph found at : http://users.vcnet.com/rrenshaw/do.html.

Our DO meter may not have been calibrated correctly, although we followed the instructions in the manual. No Lab assistants were around to help at the time.

If oxygen is dissolved in cold water, as the water heats up the oxygen will escape in little air bubbles. This can be observed in common phenomenons such as boiling water for your morning tea.

In the field site measurement, the data compared right on with the standard curve. The water at the site was saturated a normal amount compared to the data curve. The DO could change however, depending on the number of organisms living in the water and if the temperature changes throughout the day. This water was taken from an aquarium, which is heavily monitored to prevent the fish from asphyxiation and also oxygen poisoning.

The relationship between temperature and DO explains the adaptive significance of symbiotic algae within bodies of coral polyps on tropical reefs because they are located in fairly warm (35C +) water. The algae releases oxygen which the organisms living in the coral can then use to survive in the low oxygen level waters.

Trapping of infrared radiation by carbon dioxide in the atmosphere can warm the atmosphere a few degrees over the next century. This can greatly affect aquatic habitats because the surface water will be warmed more easily, releasing more oxygen and eventually having the possibility to create a hypoxic surface area on the water.