Plants use up Oxygen as well as produce it

I was reading this article and ran across something That I have never herd before. apparently when plants are in low light level conditions they actually use up oxygen. This seems like it might be of interest so some people who have extremely planted tanks



Some reasons for low dissolved oxygen levels are

* a short lighting period in planted tanks, plants produce oxygen during the lighting period and use up oxygen at night
* an overstocked tank, which translates to larger amounts of waste created that in return requires more bacteria to oxygenate the waste
* no or too little water agitation
* waste rotting in the filter or in the gravel

Another term in connection with dissolved oxygen is the Redox potential.

In simple words Redox refers to the relation of oxygen and waste particles. The more waste, the less Redox potential due to lesser oxygen. Redox can be measured in mV and the range should be between 150 to 250 mV.

Redox is also related to the biological oxygen demand (BOD). BOD is the measurement of how much oxygen is needed to break down the waste created. The higher the BOD value, the worse the quality of the water.

An acceptable BOD value is at about 1-2 mg/l (ppm).

Nitrates contribute to high BOD levels, since this generally indicates a high break down rate of waste.

In Biology 1 (highschool) it is commonly taught that plants are in the photosynthetic cycle during daylight hours which produce the sugars needed to 'power' the plant as it goes into the Kreb's cycle during night hours. So basically, at night the plant is using a similar respiration cycle that we use, which uses oxygen and releases carbon dioxide.

This is not new knowledge by any means. All plants do this.

As for the term 'Redox pontential' - I have never seen it used for the relationship between oxygen and waste products. Its raw definition is the measure of the ease at which electrons are aquired by any chemical species (molecule), thereby being 'reduced'. This is one of three acid-base relationship theories and governs the measure/calculation of pH.

2Scicrazed - Chemistry teacher by trade

2SciCrazed wrote:

2Scicrazed - Chemistry teacher by trade

no fare, CHEATER lol jk

well I just learned that seeing as I havnt done much with biology...... yet lol either way, it's intereting to know.

Interesting,

I know alot of things about plants, but never ran across that little bit of info somehow. hey, thanks for the good responce

AAAAAAH!!!!! biochemistry!!!!! (running away from horrific biochem flashbacks)

lol

I'm gonna Fishface30!

**evil laugh from the teacher!**

Night before my biochem semester final beginning of finals week, my car was broken into. They spent time rifling through my glove compartment, the center compartment, overlooked my wallet with $300 cash in it, but instead stole books and notebooks out of my book bag. Imagine the distraction my mind was in during finals the next morning. I drove to school with a broken missing passenger window.


It didn't matter anyways; I really didn't fully grasp cellular respiration and the Kreb's cycle until years later while taking anatomy/physiology. I was so excited that I had that AHA! moment on the subject!