Actually they can.
"Nitrifiers.....may survive periods of inactivity when they are periodically or persistantly exposed to anoxia, and they recover their activity instantly following O2 exposure "(Henriksen et.al., 1981).
It's true that unless you do something very drastic like boil the water, or use strong concentrations of certain chemicals, some bacteria of all types will survive very adverse conditions. But without going to any extremes, please tell me what you think generally will happen to the nitrifying bacteria colony in your bio-filter when your turn off the pump and stop the flow of oxygen rich water for several days?
You can't have it both ways, they either need oxygen to stay alive, or they don't.
And actually it's not so much that they will just die from lack of oxygen, something else goes on there in that anaerobic environment.
Here is an experiment anyone can do at home. When you're sure you have a strong thriving nirifying bacteria colony growing on your bio-media in you filter, take a portion of that media and put it in a sealed air tight container (a zip-lock bag will do), but before sealing it take a sniff of it and see what it smells like. It should have light fresh fishy smell. Now seal it up and leave it for 2 or so days at room temps, then open it and take a sniff. What you will smell is the distinct septic rotten egg smell of H2S (hydrogen sulfide) a common byproduct of anaerobic bacteria.
So what has happened?
In the absence of oxygen the anaerobic bacteria, which are always present along side the aerobic bacteria, will begin to grow and multiply. But what food is available for them to eat so that they can grow and multiply? You guessed it, they eat the aerobic bacteria themselves which had previously established themselves on the media but begin to weaken and die in the anaerobic conditions.
So this would be the same conditions in a bottle of Microbe-lift. If the bottle contained high concentrations of aerobic bacteria, they would die and become food for the anaerobic bacteria
(that will always be present) once you sealed the bottle. Sure some aerobic bacteria will always survive, but not any significant quantities, in fact there would be higher concentrations already colonizing in open oxygen rich pond water then could survive in a the anoxic conditions of a sealed bottle
.
Of course there could be other bacteria in that bottle, some that could survive in significant quantities in anaerobic conditions and aerobic conditions, in fact the makers of Microb-lift say this about their product
"Contains photosynthetic bacteria which reduces cloudy water by promoting flocculation and settling of organic and inorganic particles". Perhaps this is what is responsible for those who claim to see something favorable happening with their pond water after adding the stuff in the bottles? Keep in mind though, that these are very different bacteria then the ones we want to grow on our bio-media.
" Aerobic nitrifiying bacteria are quickly replaced (consumed) by anaerobic bacteria after prolong periods of anoxic or anaerobic conditions" (Mucky-Waters GPF.com., 2015)
