04-03-2013, 01:04 PM
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Originally Posted by pop
Good Morning Byron and other fish keepers:
I was surprised to read your post this morning. What you pointed out sounds very reasonable. We all understand that too much of anything can be an unpleasant experience. Thanks for the information about high oxygen concentrations being bad for plants (gives one some food for thought).
Your point about ‘Higher dissolved oxygen cause nutrients such as iron to bind with the oxygen’ leaves me wondering are you thinking about iron oxidation, you know rust.
Would excessive dissolved oxygen have an effect on bacterial oxidation as well altering the micro-ecology’s food chain?
I guess that I have been clarified right into another subject.
Have a good day,
I really do not have the depth of knowledge to answer this, but I accept what planted tank sources say about the binding effect of oxygen. I dug out my Walstad and came across a few points of interest.
One of the detrimental effects of undergravel filters in planted tanks is the constant circulation of oxygen-rich water through the substrate [much faster than what normally occurs]. Micronutrients like iron stay locked up in their oxide precipitates, which plants cannot use.
I also came across some data with respect to the issue of oxygen depletion at night. Oxygen like CO2 diffuses much more slowly in water than in air, some 10,000 times more slowly. Oxygen therefore has difficult escaping from the plant, and this inhibits photosynthesis by stimulating photorespiration, a wasteful process that releases fixed CO2. This can reduce photosynthetic efficiency by 20-25%.
Walstad mentions that while plants do respire continually, they prefer using their stored oxygen for this. Some 70% of the plant's interior is made up of lacunae, which are basically large gas chambers where oxygen is stored; this provides most of the oxygen for plant respiration. Oxygen is also released through the roots.