PUTTING OXYGEN BACK INTO THE WATER, PART 2

Funny things happen to your water when it doesn’t bubble enough....

Most of us are used to thinking of ‘bubbling water’ from the carbon dioxide that is in our sodas.  You open the can or the bottle and hear the ‘f-f-f-i-i-i-z-z-z-z-z’ release of the gas coming out of the solution of water and flavorings.  Or people can make the cork in the champagne bottle go flying and the fizzy wine comes running out -- it really looks great at weddings.

But we are more interested in getting a different kind of bubble -- the “ O₂ “, or oxygen -- put into the water.  That can actually happen several different ways:

Bullfrog and Duckweed at August A. Busch Wildlife Area, Weldon Springs, MO (photo: Gay Schroer) 

1.  All plants, from the mighty trees down to the simple green algaes, use water, carbon dioxide, and sunlight to make the sugars they need to grow.  This process, known as photosynthesis, releases oxygen as the byproduct.  We animals benefit from all that oxygen in the air, but few people stop to consider that algae and aquatic plants release a lot of oxygen back into the water.

Lotus plants, August A. Busch Wildlife Area, Weldon Spring, MO (photo: Gay Schroer)

2.  The temperature of the water and what level it is at also makes a big difference in the amount of dissolved oxygen that is available to the wetlands.   Since the “ O₂ “ dissolves into water the same way that other chemicals and salts do, cooler temperatures increase the amount of oxygen that the water can hold.  When the water gets warmer, more oxygen bubbles out of solution, exactly the same way that water forms bubbles when you boil water on the stove....the dissolved oxygen is leaving the solution.  The depth of the water also makes a difference in the amount of oxygen present.  During the summer, the top layers of the water have less oxygen available than the deeper levels of the wetlands.   (Pressure also plays a factor, but we can save that for a later blog).

Marymere Falls, Olympic National Forest, Washington state (photo: Gay Schroer) 

3.   Water movement -- that babbling brook that is so picturesque -- is also critical to help dissolve more oxygen.  The more the water is ‘diffused’ around, pushed, bent, even thrown up into the air with the help of a beautiful fountain, all helps bind more oxygen back into the water for the benefit of a healthy wetlands ecosystem. 

A dissolved oxygen level meter (photo: wikipedia)

4.   Dissolved oxygen levels is a measurement that environmentalists and engineers can test for.  Getting the right proportion of dissolved oxygen back into the water is critical to supporting a balanced ecosystem.  In fact, that is generally what we call the test -- we measure the “Biological Oxygen Demand” of the water (our BOD counts).  If the amount of oxygen is too high or too low, the whole system can get out of whack, causing excessive algae growth, fish kills, and other disasters that we would rather avoid.

There are other things we measure in our water samples and that will be covered in upcoming blogs.  Wait until you hear about how your poop gets recycled!

Submitted by Paula Arbuthnot, World Bird Sanctuary Part Time ETC Employee