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Re: Seachem Flourish Question

On Wed, 23 Dec 1998, Greg Morin wrote:

> One advantage with Flourish is
> that the nitrogen source is in the form of amino acids which are
> utilized as preferentially as ammonia is and even if the amino acids
> are broken down by bacteria, it is broken down in to ammonia first
> which can be utilized by the plants as well.

My reading doesn't confirm the idea that amino acids can be used directly
by plants.  I suspect that if this is true the ability to use amino acids
is going to depend very sharply on which acid you're talking about.  Can
anyone else confirm/deny this assertion?

> I had a question for you as well: Why did you think that the cyano
> problem might be attributable to low nitrate levels? By cyano I
> assume you mean the blue-green "algae"? According to Baensch Atlas
> volume 2 pg 162, the blue-green algae aka cyanobacteria can flourish
> in the following conditions:  strong sunlight, rotting substrate,
> excess feed, too few water changes, overfertilization or _high
> nitrate levels_. If you are having a cyanobacteria problem I suspect
> one of the other conditions to be the cause since you report that the
> nitrate levels are low.

I'll horn in on this, too.

I think we see two different kinds of cyanophyte occurences in tanks.  The
one that is described above is found mostly in neglected tanks. Under
those conditions, the cyanophytes tend to grow explosively, pose a serious
nuisance, and threaten to smother all of the plants in a tank.  The
infestation also rebounds very quickly (in a single day, for instance)
after it is mechanically removed.

Cyanophytes are also found in slow-growing patches and films, usually in
out-of-the-way places.  When the patches are mechanically removed they
recover relatively slowly (say, over the period of a week or two) and
don't threaten to smother the plants. This infestation isn't normally much
of a nuisance but if you don't do something about it, it can slowly
increase in size until it does become a problem.  This can happen in
well-maintained tanks and it's probably this sort of infestation that is
found at low nitrogen levels.  At least some cyanophytes are capable of
fixing nitrogen; at low concentrations of ammonia and nitrate most algae
growth is surpressed, so the cyanophytes can grow with less competition
for other dissolved nutrients - notably phosphorus.

In either case, the cyanophytes are probably competing successfully under
conditions with a low N:P ratio, which is consistent with the findings
that Mark Fisher paraphrased a few days ago.  In the first case the high
nutrient levels allow rapid growth; in the second case the low nutrient
levels allow only slow growth.

Roger Miller

In Albuquerque, pondering the fine line between intellectual synthesis and
sheer speculation.