NO3 level and growth of aquatic plant ref: Paul Krombholz 1966

I was thumbing through a well known, but older Limnology text
(Hutchinson, 1975, Vol 3 Limnological Botany pg 351-357) when I saw a
nice graph showing growth rate vs NO3 concentration.

It seems Paul had found that 20-80 ppm and above was the ideal range
for submersed plant growth(Vallisneria americana) back in the
1960's(1966). I suppose I redisocovered this range(20-75ppm)
independently some 30 years later thropugh trial and errors.

What is interesting is that we both arrived at the same range. At
progressively high concentrations, this high rate of growth slowly
decline, but very slowly.....even at 100ppm etc.

This also mirrors my own observations when I did longer term NO3 at
75ppm for several weeks.

What is really interesting is how rapid the growth rate increases when
the level is maintained.

For example:
At 5 ppm the rate of growth is greatly reduce, about 2.2/0.7= 3.14
times less growth (dry weight mass).
At 10ppm, the growth was about 1/2, 2.2/1.1 = 2x less growth than at
20-80ppm.
After 20ppm, the plant's growth is no longer nitrogen limited.

Fast forward to the molecular age of plant biology.
Why might these plants show this pattern? How would they control it?
Given what is known about LAT and HAT transportors for NO3, it may now
be suggested that when plants have all their constitutive and
inducible transporters upregulated and maintained, they grow faster
and have non limited growth.

In order for the plants to do this, 20-30ppm of NO3 needs to be
present in the medium(the water column). Now we have a plant that is
healthy and can grow at a maximum rate. If the NO3 levels varies
between say 2-15ppm, then the various transporters will be degraded
and more efficient transports(the HATs) specific to low NO3 levels
will be put in their place. As a result, the plants growth rate will
be reduced.

It takes more energy to concentrate nutrients when there is less in
the external environment. So at higher levels, the plants use
different transportors that take full advantage of the higher NO3
levels and grow faster as result.

PO4 data was also discussed. But no such graph was provided, other
than tissue analysis for PO4.Still if one assumes a ratio for PO4,
then a 6:1 to 10:1 relationship would suggest about 2ppm or higher for
PO4(Conversion from N:P to NO3:PO4 is addressed FYI).

Which is about what we find to be optimal for growth in the water
column.
Seems the data was and has been there all along, just no one bothered
to listen to Paul, nor look stuff up.

He looked at many lakes and plants and did a lot of tissue analysis
beside this as well. Below is my personal favorite of Paul at the
plant fest, he should stick to plants:-)

Reference:

Gerloff, G.C., and Krombholz, P.H., 1966. Tissue analysis as measure
of nutrient availability for the growth of aquatic plants.
Limnological Oceanography, 11:529-537. (Hutchinson, 351-357)


Regards,
Tom Barr

www.BarrReport.com
www.sfbaaps.com
www.gregwatson.com

wrote in message
ups.com...

It seems Paul had found that 20-80 ppm and above was the ideal range
for submersed plant growth(Vallisneria americana) back in the
1960's(1966). I suppose I redisocovered this range(20-75ppm)
independently some 30 years later thropugh trial and errors.

What is interesting is that we both arrived at the same range. At
progressively high concentrations, this high rate of growth slowly
decline, but very slowly.....even at 100ppm etc.

This also mirrors my own observations when I did longer term NO3 at
75ppm for several weeks.

What is really interesting is how rapid the growth rate increases when
the level is maintained.

Hi Tom,
Though I am only a layman, these levels of nitrate seem a little
frightening, especially to an ex-marine hobbyist. I always thought that
anything over 30ppm caused real stress in any fish stock (though I repeat,
I'm only a layman). The higher levels, 50ppm plus, must surly have a
detrimental effect on any of the slower growing plant species? After all
eutrophication has proved to be a problem in many smaller bodies of water,
though I need to admit that I'm struggling to understand the chemistry
involved. Just put it down to my age and the resultant death of brain cells
;o)
Regards David

On Mar 24, 3:24 am, "David Kershaw"
wrote:
wrote in message

ups.com...



It seems Paul had found that 20-80 ppm and above was the ideal range
for submersed plant growth(Vallisneria americana) back in the
1960's(1966). I suppose I redisocovered this range(20-75ppm)
independently some 30 years later thropugh trial and errors.

What is interesting is that we both arrived at the same range. At
progressively high concentrations, this high rate of growth slowly
decline, but very slowly.....even at 100ppm etc.

This also mirrors my own observations when I did longer term NO3 at
75ppm for several weeks.

What is really interesting is how rapid the growth rate increases when
the level is maintained.

Hi Tom,
Though I am only a layman, these levels of nitrate seem a little
frightening, especially to an ex-marine hobbyist. I always thought that
anything over 30ppm caused real stress in any fish stock (though I repeat,
I'm only a layman). The higher levels, 50ppm plus, must surly have a
detrimental effect on any of the slower growing plant species? After all
eutrophication has proved to be a problem in many smaller bodies of water,
though I need to admit that I'm struggling to understand the chemistry
involved. Just put it down to my age and the resultant death of brain cells
;o)
Regards David

There are no known detrimental effects on plants at extreme levels(NH4
is quite another matter), fish and the most sensitive will be Amano
shrimps etc.

I used these shrimp in a toxicity study, I found no adversed effects
at 160ppm(the limit of the test method, it was likely higher). No fish
or plant impacts where noted. I used KNO3 to dose, as did Paul.

Note: KNO3 and waste derived via fish waste are radically different.
What does fish waste start as? It does not start as inorganic NO3, it
starts as extremely toxic NH4.

If you try and add 160ppm NO3 via Fish waste, how different do you
think the outcomes would be?

I'll give some examples: 0.2 ppm is typically lethal short term
effects for many fish/inverts etc.

Take a look at trout, daphnia, algae for NH4/NH3, then compare to NO3.
13,000X to 280X more toxic in many long and short term studies.

Even if a cheap test kit can measure the lower ranges of NH4, they are
often used, but the plants/shrimp/fish are still exposed to low
levels.

Planted tanks are so successful and provide optimal health not due to
low nutrients, rather WHICH nutrient and which form(NH4 vs NO3).

Assuming that these are on equal terms is an apples vs oranges
argument.
We are doing horticulture here, adding fertilizer to increase plants'
growth. Most aquarists from the fish only world see NO3 as a
pollutant, whereas a farmer sees it as a fertilizer.

By adding a form of N that is inorganic and the most bioavailable to
plants, you maximize growth.

Adding CO2 causes no outrage, yet it is far from a good thing for fish
also. What is really providing good fish health in our tanks then? Are
the nutrients like NO3 actually that bad?

Oh............"it's a fertilizer to help the plants grow
more........not a pollutant"

Have folks used/tested KNO3 and aggressively removed all forms of NH4
as well? I've never seen such a study.

Applying non comparative research is not wise.
Marine systems are worse, your pH's are far more slanted to the more
toxic NH3 side of things.

So rather than using fish food in that case, adding KNO3 to drive
higher PO4 uptake in a refugium works far better. This also keeps a
number of the species from melting/going sexual, see RC's forums for
more on that. Typically about 5ppm works nicely. Some NO3 gets
denitrified in the DBS obviously, but the rates are pretty low due to
slow diffusion.

I think very clean water is water without NH4, and high O2 levels.
Adding KNO3 provides that, adding NH4 and having cycle through the N
cycle removes a lot of O2 along the water, and exposes fish/inverts to
NH4/NO2.

If anything messes with the bio filter or uptake, then you get a back
up, even if small for a few hours, it can cause serious effects and
folks just do not test things, they assume way too much about such
nutrients.

Do they test and see if adding progressively more and more fish does
the same effect at the similar NO3 levels?
No, never seen that study.

Do they add NH4 in the inorganic form and see what occurs?
No, very few have ever done that, nor do I suggest folks try it unless
they are okay with algae blooms and dead critters. Might be an ethical
issue, but such knowledge can help provide better conditions for your
critters and everyone's later. Never met an aquarist that was never a
fish killer, so the ethic issue is fairly easily resolved.

I'm not suggesting adding more than 50ppm, but if it hits that range,
that's okay, the water change will drop it back down and maintain and
nice range of 20-30ppm in most systems using CO2/fully planted by
doing 50% weekly water changes and dosing about 5-10ppm NO3 from KNO3
3x per week(20-30ppm a week).

I figure if I have many rare South American fish that are wild caught,
as well as many other species that sensitive, inverts etc, and they
breed(Discus/shrimps etc), and a tank full of Altums for a client, and
they all do well and have for decades, I'd like to see someone show me
how and why these fish are stressed out vs a tank with a few ppms of
NO3.

Tanks look 1000% better than bare tanks also, the plants suck the NH4
and the bare tanks don't. the feces hang out and leach the NH4 into
the water column first..........then it goes to the filter or is
removed via a water change, but it has all day sitting there before
that happens.

Plant tanks?
Plants are packed all over the tank, sucking out PO4/NO3/NH4/Fe and a
dozen others.

I think the observations and simple test to test your own hypothesis
is wiser. Then you know rather than believing what is said and how
it's applied.
Acute vs chronic effects are an issue but if it does not influence
behavior/reproduction/breeding/disease and these are higher in planted
tanks than without, you have to wonder and question things.

Regards,
Tom Barr

Thanks Tom,
It looks like I have to back down ;o) Though I am still
a little unsure about slow growing plants from a low nutrient environment
being subjected to high levels of nitrate and having to compete with faster
growing species, I'm probably thinking more like a gardener than an
aquarist. I will concede the argument, potassium nitrate is a very different
animal to the nitrate resulting from the breakdown of ammonia. Thanks again
for taking time to explain.
Regards David

On Mar 24, 3:29 pm, "David Kershaw"
wrote:
Thanks Tom,
It looks like I have to back down ;o) Though I am still
a little unsure about slow growing plants from a low nutrient environment
being subjected to high levels of nitrate and having to compete with faster
growing species, I'm probably thinking more like a gardener than an
aquarist. I will concede the argument, potassium nitrate is a very different
animal to the nitrate resulting from the breakdown of ammonia. Thanks again
for taking time to explain.
Regards David

Well, think about this in terms of a reef person growing macro algae
in a refuge.
If you want to remove PO4 using the macro algae, why would you
severely limit NO3 as well?

The DBS needs a souce of NO3 to maintain a good rate of removal also,
and a carbon source like the macro algae leeching photsynthate.

Such concepts apply not only to FW, but Marine systems to some degree.
What occurs if you overstock the marine tank?
NH4= algae etc
NO3 to the same amounts N for N?
Macro algae growth.

Easy test.

Few will ever try or do it sadly.

Regards,
Tom Barr

In article . com,
wrote:
There are no known detrimental effects on plants at extreme levels(NH4
is quite another matter), fish and the most sensitive will be Amano
shrimps etc.

I used these shrimp in a toxicity study, I found no adversed effects
at 160ppm(the limit of the test method, it was likely higher). No fish
or plant impacts where noted. I used KNO3 to dose, as did Paul.

I slipped a decimal once and dosed at 200 ppm of know instead of 20.

I let it go for 3 weeks to see what would happen. The tips of a couple
of crypts curled a little bit but the 16 ammano shrimp were unaffected.

--
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Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net

On Mar 25, 6:02 pm, (Richard Sexton) wrote:
In article . com,

wrote:
There are no known detrimental effects on plants at extreme levels(NH4
is quite another matter), fish and the most sensitive will be Amano
shrimps etc.

I used these shrimp in a toxicity study, I found no adversed effects
at 160ppm(the limit of the test method, it was likely higher). No fish
or plant impacts where noted. I used KNO3 to dose, as did Paul.

I slipped a decimal once and dosed at 200 ppm of know instead of 20.

I let it go for 3 weeks to see what would happen. The tips of a couple
of crypts curled a little bit but the 16 ammano shrimp were unaffected.

--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff:http://mbz.org
1970 280SE, 72 280SE | Home pages:http://rs79.vrx.net
633CSi 250SE/C 300SD |http://aquaria.nethttp://killi.net

Well, 3 weeks is a good time frame.
I just did a 3 day acute, but that did not address the fish waste and
other residual NO3, that's just what was added on top of what was
there, added internally.

I know that it was at least 160ppm, my the method did not go beyond
that.
Good old fashion accidents that should cause algae, dead fish etc
occur a lot, but observations etc help a lot and them following them
up.

Regards,
Tom Barr


Regards,
Tom Barr

In article .com,
wrote:
On Mar 25, 6:02 pm, (Richard Sexton) wrote:
In article . com,

wrote:
There are no known detrimental effects on plants at extreme levels(NH4
is quite another matter), fish and the most sensitive will be Amano
shrimps etc.

I used these shrimp in a toxicity study, I found no adversed effects
at 160ppm(the limit of the test method, it was likely higher). No fish
or plant impacts where noted. I used KNO3 to dose, as did Paul.

I slipped a decimal once and dosed at 200 ppm of know instead of 20.

I let it go for 3 weeks to see what would happen. The tips of a couple
of crypts curled a little bit but the 16 ammano shrimp were unaffected.

Well, 3 weeks is a good time frame.
I just did a 3 day acute, but that did not address the fish waste and
other residual NO3, that's just what was added on top of what was
there, added internally.

I should also point out that although these 16 shrimp survived 3 weeks
at 200 ppm nitrate with zero obervable effect, the same is NOT true
for ammonia.

A few months later I got a large number of emerse grown crypts and put them
in the same tank. Of course the first thing an emersed crypt does underwater
is let its leaves melt and rot. One day 2/4 of the shrimp appeared dead
and white - not pink. I moed them all to a clean tank and nearly all recovered.

The ammonia level in that tank BARELY registered on my test kit.

So yeah, nitrate good, ammonia bad. The fish and plants didn't care, but
the shrimp are much more sensitive.

--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net

wrote:
I was thumbing through a well known, but older Limnology text
(Hutchinson, 1975, Vol 3 Limnological Botany pg 351-357) when I saw a
nice graph showing growth rate vs NO3 concentration.

It seems Paul had found that 20-80 ppm and above was the ideal range
for submersed plant growth(Vallisneria americana) back in the
1960's(1966). I suppose I redisocovered this range(20-75ppm)
independently some 30 years later thropugh trial and errors.

snip

Thanks, Tom!
I ventured onto Usenet again on a late-night impulse and here's some
real science. :-)

The info about HAT and NAT transporters has some interesting
implications. I had always assumed that it was OK to allow nitrates to
rise and fall with water changes. Looks like if NO3 falls too far,
plants induce HAT transporters and the next dose of fertilizer does no
good. Interesting...

I wonder how fast algae adapts vs. higher plants.

--
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http://groups.google.com/group/The-Freshwater-Aquarium
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