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[APD] Re: BGA, N2 gas and heterocyst

Date: Wed, 2 Mar 2005 08:59:18 +0100
> From: "Daniel Larsson" <defdac at hotmail_com>
> Subject: [APD] BGA/Cyanobacteria
> To: <aquatic-plants at actwin_com>
> The single most effecive sellingpoint, to me, for using KNO3
> against Cyanobacteria/BGA is "heterocysts":
> http://www.answers.com/topic/heterocyst

Well, that does not apply to Oscillitoria.
They don't form heterocyst, no heterocyst with this group=> no N2 gas fixing.
Azolla/Anabeana are the only N2 Fixing cases in the aquarium and you'll note: it's very green in  tanks, yet often very red in swamped ponds(and duckweed is absent). Very red=> low NO3. High duckweed growth=> good Nitrogen levels.  

>These specialized cells extract nitrogen ...
> *drum roll*
> ... from the air.

Except that they are clearly absent from Oscillitoria.

> If you can't get rid of Cyanobacteria/BGA, you will have nil
> growth on plants and probably on other algae too.

True but it's not because of N2 gas, their needs like other small algae like Green water, are very small.
As such, they are not N limited in a relatively directy tank with lots of plants which leak out nutrients and substrates, high relative fish loads vs natural systems and dosing etc occuring.

> Fishfood/fishpoop will not get you far if you have nitrogen
> starving plants, 

But will supply plenty to the BGA, no need to invest energy and resources to go after N2 gas.
There are some BGA's that fix N2 gas without heterocyst..............but not this group/genus.  

> // Daniel.

Tom Barr
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