Oxygen

Dissolved oxygen (DO) is necessary for aquatic life in order to survive. Dissolved oxygen is measured in PPM or parts per million. Parts per million is the number of "parts" by weight of a substance per million parts of water. Fast moving water tends to have large amounts of oxygen, while slower moving water, especially stagnant water, has lower levels. Colder water tends to have more dissolved oxygen than warmer water. Most dissolved oxygen is introduced into water through aeration, flowing over rocks, or as a waste product of photosynthesis. It is generally considered that DO levels of at least 4-5 PPM are sufficient for most aquatic life, however, good fishing waters average about 9.0 PPM.

 

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Step 1: Rince the glass vial thoroughly 3 times.

Step 2: Fill the glass vial completely full with water.

Step 3: Get 2 dissolved oxygen tablets and place in the vial.

Step 4: Screw the black cap onto the vial.

 

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Step 5: Wrap your hand around the vial.

Step 6: Shake the Bottle in your closed hand, until the tablets are dissolved.

 

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Step 7: Use the comparator to determine the amount of dissolved oxygen in the water sample.

Step 8: Record your findings on your data sheet (Design Process: Water/Chemical Analysis).