NO3 level and growth of aquatic plant ref: Paul Krombholz 19

BarrReport · Joined: 16 Aug 2007 Posts: 55

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 Razz

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

Archived from group: rec>aquaria>freshwater>plants

David Kershaw · Joined: 16 Aug 2007 Posts: 14

wrote in message @y80g2000hsf.googlegroups.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

David Kershaw · Joined: 16 Aug 2007 Posts: 14

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

Richard Sexton · Joined: 16 Aug 2007 Posts: 210

In article ,
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

BarrReport · Joined: 16 Aug 2007 Posts: 55

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

BarrReport · Joined: 16 Aug 2007 Posts: 55

On Mar 25, 6:02 pm, rich...@news.vrx.net (Richard Sexton) wrote:
> In article ,
>
> 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

Richard Sexton · Joined: 16 Aug 2007 Posts: 210

In article ,
wrote:
>On Mar 25, 6:02 pm, rich...@news.vrx.net (Richard Sexton) wrote:
>> In article ,
>>
>> 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

Altum · Joined: 16 Aug 2007 Posts: 4

BarrReport@gmail.com 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.

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

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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