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Re: nitrifiers

> <itty-bitty, unsignificant bit of information>
> Recent research, written about in AFM and on the web as well (I don't have
> the URL, but it should be fairly easy to locate via search) used genetic
> probes to learn more about nitrifying bacteria in aquatic environments.
> Although we know that nitrifiying bacteria do exist, the nitrobacter and
> nitrosomonas bacteria that are found in soils (and claimed for the last 30
> years to be the reason for nitrification in aquaria) were not found in
> cycled freshwater aquaria, to which ammonia was added regularly and the
> aquarium cycled, and only one of these (I think it was nitrosomonas) was
> found in marine aquaria in the same set of tests.  Further research will
> hopefully identify the bacteria that are actually responsible for aquatic
> nitrification.  It was a very interesting article and made me realize how
> much is just taken for granted within the aquaria hobby.
> </itty-bitty, unsignificant bit of information>

I think its interesting, and I'm glad someone's doing the research...

It is long-standing dogma that nitrosomonas and nitrobacter are
responsible for nitrification in aquaria, but I've seen no actual
documentation for that.  I've read of two other genera of nitrifying
bacteria (nitrospira and nitrosolobus) that do ammonia->nitrite
conversions in freshwater and another (nitrosococcus) that will do it in
marine environments.  The nitrite->nitrate conversion in fresh water is
done by nitrobacter, while nitrospira and nitrococcus can perform that
duty in salt water. 

I'm not sure that it makes much difference.  All these bugs are 
Gram-negative and they do pretty much the same thing.  I've taken the 
view that ammonium is a "high grade" nitrogen source for my plants.  From 
that perspective the nitrifying bacteria are actually bad guys because 
they convert the ammonium to relatively "low grade" nitrite and nitrate.  
I no longer encourage them more than I have too.

Roger Miller