[APD] Re: Cyanophyta

[Thomas Barr <tcbiii at yahoo_com>]

"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"

For same reason algae thrive at low plant limiting nutrient
levels, they simply are better adapted to low nutrient levels.
If you have a 1 acre plot, you might only be able to raise on
elephant. But you could rise 50,000 mice.

If you reduce the food on this same piece of land by 1/2, the
mice will only be 25,000, but 1/2 an elephant?

You just don't see 1/2 elephants roaming around.

So like plants and algae, this is often the case.

Plants take long to respond but when they do, they remove and
store nutrients in greater amounts. This is why blackouts work
on smaller algae, vs larger algae and plants.

There are other issues for this difference in terms of
competition, surface/volume ratios, Km affinities for uptake of
nutrients by enzymes vary with plants vs algae and carbon
sources etc. 

When DOC or any dissolved organic nutriets that are
bound/complexed in some way are broken down and released, these
high affinity enzymes are ready to get them as soon as they are
produced, plant enzymes are  more adapted to much greater
nutrient concentrations in order to work the best.

There are numerous competition models depicting this
relationship in literature, this is nothing new.

As the other end of the scale, why do BGA's flourish in very
high levels of nutrients?

Well a few things are going on here. But that's another
post..........:)

Regards, 
Tom Barr





  







 







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