I am not sure what you mean by "make it harder", but if you are
implying that high NH3 levels kill the nitrobacter than what is the
ED50 for this? Furthermore, is the ED50 less than the maximum
concentration of NH3 that is normally reached during cycling? Is this
something you found out after doing some research on your own? Heehee
hee heee, snicker!

I've heard this claim before--Wayne Sallee did not just pull it out of his
ass through personal or unscientific observation. I believe there is
research out there to back it up.

Than you must know what he means by "real high ammonia levels makes it
harder on the bacteria"?? I sure don't What do you think he means by "make
it harder"?

I would love to read some literature on this phenomenon.


I am uncertain myself if there is a direct relationship between the levels
of free ammonia and the efficacy of nitric bacterium

I am not aware of any literature that claims that high concentrations of
ammonia (within the realm of a normal cycling) decreases the efficiency of
nitrobacter to metabolise NO2-.

Read the link I provided (first one I came across, I'm sure there are
others) under the heading nitrifying bacteria on the relationship between
NH3 and microbe population. They state (as I have) that the concentration
of the nitrifiers (bacteria) depends on the rate (increased rates yield
increased concentrations) of NH3 production. The faster the rate (and thus
the greater the concentration) the higher the population of both microbes
(nitrobacter and nitrosomonas).

http://www.cci.unl.edu/Teacher/NSF/C...thotrophs.html

or an indirect one in
which the relationship is as simple as the fact that the conversion of
nitrite into nitrate requires more oxygen and more energy than the
conversion of ammonia into nitrite and therefore nitrous bacterium have
easier access to available oxygen.

You are missing the entire point as to why these bacteria are metabolising
NH3 and NO2- in the first place. This process of converting NH3 into NO2-
and NO2- into NO3- does NOT consume energy it PRODUCES energy. This is how
these bacteria produce their metabolic energy (ATP).

I'm not sure which bacteria (nitrobacter or nitrosomona) consume the most
o2.

Hopefully the previous poster can
produce some referenced material to clear this up.

Doubtful