Monday, July 20, 2015

Putting Oxygen Back Into The Water..Part 1

The water you drink . . . .it is full of stuff, even when you drink filtered water -- and that is a good thing!

The water that you bathe with, the stuff that comes out of the tap, the stuff that was deemed ‘safe’ by the local water company for you to drink, is full of stuff, too -- and that’s a good thing!

Dissolved oxygen .jpg 
The water that we call ‘rain’….it may have traveled thousands of miles from the ocean where it was picked up.  It may have floated over many hundreds of smoke stacks before it landed in our gardens and is also full of stuff, but this “stuff” may not always be a good thing if it has turned into acid rain.  Chances are, the rain also picked up a bunch of other stuff like soil and particulates, and that is usually a good thing!

Yes, the first thing that comes to mind is that water -- that clear, effervescent, necessary ‘gold’ that, unfortunately, we take for granted -- is usually full of stuff like minerals and microscopic life that is needed to keep us humans and other critters alive. 

Water, even purified and bottled water, is full of dissolved minerals, necessary for us humans to take in for all of our nutrients.  These minerals occasionally add flavor to the water when you taste extra iron or calcium.  And it might scare us modern humans to think that we are swallowing microbes, afraid that they could make us sick when, occasionally, these microbes DO make us sick.   Who knows what else was in that innocent-looking, plain, colorless glass of water that went so far to keep us alive, that satisfied our thirst, that got brewed into that delicious cup of java in the morning?

Most of us who took chemistry class in high school learned that the formula of “ H2O ”  was supposed to represent water -- 2 atoms of Hydrogen was bound together with one atom of Oxygen.   Most of us were taught about the chemical bonding, the chemical ‘attraction’ between these atoms, which always set up this wonderful ratio.  But if this was all that was ever in the water we drink, it would not be enough to help sustain life. 

Yellow-crowned Night Heron feeding on a Crawfish in Francis Biedler Forest, North Carolina…a demonstration of the “food chain” (photo: Gay Schroer)

Now, most of us are well aware that chemicals, minerals, soil, and all kinds of stuff can be dissolved into that water and that we need all that stuff to stay healthy.   Most of us have learned that fish can filter the life-giving oxygen out of the water across their gills as their version of ‘breathing.’  Most of us have learned that aquatic plants even pull oxygen out of the water to make the simple sugars that keep the plants alive, the microscopic organisms, the next level of creatures, etc., all the way up the predator chain.

But sometimes, it is not so much what was in that mouthful of wet that you just swallowed.  A large part of this story is about what it wasn’t.

What happens when you don’t have enough dissolved oxygen in the water?   Yes, unfortunately, you can have a whole pond or other large body of water -- all wet and wonderfully cool and surprisingly dead -- that is lacking in enough oxygen in the water.  It is a condition called ‘Low Dissolved Oxygen. It is a rather dangerous condition too, causing massive fish kills or unwanted algae growth and other out-of-balance conditions to the environment that affects both plant and animal life, both upstream and downstream, of the body of affected water.

Dorothy Falls, Lake Kaniere, South Island, New Zealand…falls such as this help to introduce extra oxygen into the downstream water (photo: Gay Schroer)

The ‘dissolved oxygen’ that we need in water is actually extra oxygen free floating in the water and it has a separate chemical symbol, shown as “ O2“.  It is a chemical bond between two oxygen atoms, bound only to each other and not to any hydrogen atoms.  It is this ‘dissolved oxygen’ that the microbes, plants, and fish grab out of the water to perform their bodily functions. The “ O2“ molecules (more than one atom) get put into the water by a variety of mechanisms:  most generally from the photosynthesis of plants releasing leftover oxygen into the water; bubbling and babbling brooks add extra oxygen from the turbulence, and even rain and lightening will help add extra oxygen back into the water.

We humans, particularly the environmentalists and engineers, have learned that there is a measurable quantity of “ O2“ that must be present in the water in order for it to be considered healthy.  If the amount of oxygen is too low in the water, then the plants can’t fully take up the soil’s nutrients, the microbes won’t process the chemicals, and the fish will suffocate.

Ultimately, we all know what that means -- no fish, no raptors and many other birds.

Check back with us next month when we have to start putting the oxygen back into the water......

Submitted by Paula Arbuthnot, World Bird Sanctuary Part Time Employee

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