RE: [APD] RE: Cyanophyta/BGA (Thomas Barr)

[Phil Bunch <pbunch at cox_net>]

What nitrate levels are conducive to BGA growth. I'm pretty sure this 
varies with other parameters but perhaps there is a relatively 
straightforward answer.

Phil Bunch


On Thursday, December 11, 2003 08:10, Dirk_Matthys at toyota-europe.com 
[SMTP:Dirk_Matthys at toyota-europe.com] wrote:
>
> Hi all,
>
> I had some BGA infestations which I could eliminate using the highly
> patented TB approach. So I can attest that it worked in my case at least.
> ( see the grey slime thread some time ago ) I was low on nitrates and 
since
> I cleaned up and increased N dosing it hasn't come back aggresively. The
> moment I see the "first clearly visible" trace of BGA, I measure nitrate
> with my worthless test kit and immediately increase the KNO3 dosing 
anyway.
> This beats back the BGA in most cases within 24H. FWIW, when my plants 
are
> slowing down and yellowing I can expect a BGA outbreak within1-2 weeks.( 
or
> some plants get really red heads, hygrophilla is my main indicator )
>
> I have gone through "thekrib" and this digest several times and could 
find
> some controversy. From most references it is clear that BGA are excellent 
N
> competitors since they seem to thrive in low nitrate environment.( I
> believe same can be said for extremely high nitrate to a lesser degree,
> but I have no evidence of that, pls correct me if wrong ). It is usually
> stated that BGA can fix atmospheric N ( general BGA statement )
> But Tom Barr wrote: ( and I thrust advice from experienced people ,
> especially with a scientific or emperical approach)
> "For our tanks, it appears as a result of high DOC with very low NO3.
>  The genus that infest our tanks is Oscillitoria andf it is a filamentous
> non heterocyst forming species, therefore it does not fix atmospheric
> nitrogen, since heterocycst are require in this genus at least, to fix 
N2"
>
> If the species we get in our tanks do not fix atmospheric N, then why are
> BGA bacteria good competitors vs algae/higher plants? Are there other
> mechanisms in BGA that can retrieve N from more compounded substances? 
 Or
> do they need very little to survive and they strip the water for every
> molecule that comes available from other processes? Anything else?
>
> thanks for any advice!
> suisoman Dirk
>
>
>
>
>
>
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