Re: cobalt and 'cracking' ammonia

David Whittaker wrote----
>Many algae and probably plants manufacture B12, so maybe they require

My plant science text (Raven & Evert, fifth ed, 1992) does not list cobalt
as one of the micronutrients.  What that means is that cobalt has not been
shown yet to be an essential nutrient.  Perhaps with improved methods of
purifying nutrient media of cobalt, someone will sometime demonstrate a
need for cobalt.  What it means for us in the hobby is that we don't have
to worry about adding cobalt.  If plant nutritionists haven't yet been able
to purify their nutrient solutions of cobalt to a level low enough for
cobalt deficiency to appear, assuming plants need it, then we don't have to
worry about cobalt deficiency showing up in our plants.

Helen Nash (HNH2Ogar at aol_com), wrote----
>Date: Mon, 16 Oct 1995 09:48:12 -0400
>Subject: ammonia
>I'm about ready to re-enroll in college to find the answer to this one.
> There's a young pond-builder-nursery owner on the water garden message board
>of AOL who claims that aeration breaks the bond of ammonia.  He says that
>"water in its entirety has more affinity to oxygen than it does to ammonia.
> Ammonia is pushed out with the introduction of oxygen, with the water being
>cold during the winter the chain reaction from cracking the ammonia loose is
>one benefit, the other is the actual cracking of the ammonia molecule itself
>into the two gasses that it is made up of.  The byproduct of this is plain
>old nigrogen which is gobbled up by the first algae bloom in the spring,
>before the bio-filter kicks in.  Cold water holds more air and less ammonia
>by nature.  The introduction of the air forces out the ammonia, the
>instability of the ammonia from the separation causes it to crack again into
>the two gasses which are carried out by the water bubbles to the outside."
> He has stated that he has smelled ammonia in the water, tested positive for
>ammonia, heavily aerated, then retested negatively.  What is the scientific
>explanation of why or why not aeration breaks the bond of the ammonia
>molecule and allows its removal from the water naturally?
>Thanks for your help with this quest for some real science!
>Helen Nash

This nursery owner needs to go to college, or maybe even to high school!  I
have rarely seen such errant nonsense!  If oxygen is present, ammonia gets
oxidized by bacteria first to NO2, nitrite, and finally to NO3, nitrate.
The oxidation process is called nitrification, and the bacteria are the
ones that are supposed to find happy homes in our biofilters so that we can
have pounds of fish in our tanks.

Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174