Nitrates always good for aquatic plants?

[paludarium]

Hi Tom,

An interesting study from the Netherlands demonstrated that high water column NO3 concentrations can significantly reduce the growth of ammonium preferring rooted submerged species such as P. alpinus, particularly on sediments with a relatively low nutrient availability. http://www.bureaudaslook.nl/Pdf/Freshwater Biol.pdf This reminds me of EI, and also some complaints by the hobbyists about weird plants growth after dumping KNO3.

Any comments on this issue?

Regards,
Erich

 

[Tom Barr]

These plants where not CO2 enriched, and the sediments plain sand, vs mud are very different and produced predictable results.

The treatment: 0 ppm of NO3 and then 500umol of N-NO3.
Convert umols (to ppm 62 gram mol).
62 grams in 1 liter = 1mol/l or 62,000 mg/l



31ppm.

Is this N-NO3 or just NO3?
136ppm vs 31 ppm is a large difference.
I'll assume 31 ppm of NO3.

Still, I agree with their conclusions based on the results, but this is for only one species of pondweed, and the sediment effects can play a role as well there was no CO2 enrichment occurring.

Also, was the plant adapted to the NO3 prior?
Does this also really influence the total growth over an entire life cycle, growign season?

Or just the few weeks the study was done(as is often the case for many of these aquarium nutrient studies)???

The single species, adapted prior to the test, interactions with sediment sources of NH4(note, there was not a large difference when the NH4 was present in the sediment vs plain sand) all these make large difference in what we can say about all tropical aquatic plants(this is a cold water species that was tested).

For this species, seems a good nutrient rich sediment and decent NO3 woukld be fine and not affect growth much, nothing we could/would see.

I rarely dose more than 15ppm at a time of NO3, but I've not seem adverse effects in communities of plants at 30ppm either.

There is not need to go beyond 20-30ppm, you will not get higher rates of growth. While significant, the rates where also not that different.



Regards,
Tom Barr

 

[JDowns]

Unless I missed it where/how was Carbon maintained? If N is no longer a limiting nutrient can growth decline be attributed to too much N or not enough C. Especially in a controlled environment at those Par levels for a 16hr photoperiod. The observation of P reduction in the aquaria with elevated N would not be a surprise. N is no longer a limting variable.

If I setup a tank with a par of 100 mmols at the surface and 65 at the plant surface. Added N in a non limiting fashion. I would not be surprised that P would become scarce and general plant health declined without a good steady C supply.

I would think to attribute one nutrient as a positive / negative factor in growth all other nutrients would have to be non limiting.

 

[JDowns]

Ninja'd by Tom.

 

[paludarium]

These plants where not CO2 enriched, and the sediments plain sand, vs mud are very different and produced predictable results.

Correct me if i am wrong.

The authors indicated that uptake,reallocation and reduction of NO3 by plants have a much higher energy and carbon requirement than NH4 uptake and assimilation. So if we dose NO3 instead of NH4, we also have to raise CO2 levels, otherwise the plants might show stunted tips, which were correlated to high NO3 levels but actually were caused by limited CO2.

Regard,
Erich

 

[Tom Barr]

Correct me if i am wrong.

The authors indicated that uptake,reallocation and reduction of NO3 by plants have a much higher energy and carbon requirement than NH4 uptake and assimilation. So if we dose NO3 instead of NH4, we also have to raise CO2 levels, otherwise the plants might show stunted tips, which were correlated to high NO3 levels but actually were caused by limited CO2.

Regard,
Erich

Yes, perhaps, at least for P alpininus.
Some plants do very well with NO3, others NH4, most do best with a combo of both.

NO3 is used much like an osmotic salt inside the vacuole.
K+ , Na+, and NO3 mostly.

I think you may be interested in the idea that NH4 instead of NO3, is a good way to reduce CO2 ppm's. This study might suggest it some, but sediments play a large role there also for NH4.

So a ratio of NH4 and a various levels of NO3 where not done for this study.
See the Cedergreen/Madsen study for nutrient rich streams from Denmark.

Regards,
Tom Barr

 

[paludarium]

Well, I tried to find the answers. Many local hobbyists abandoned EI methods due to stunted tips or curling leaves esp. of Rotala macrandra, Alternanthera reineckii and Amannia gracillis etc. Crank up the CO2 more may help to resolve the problems. However many aquarists also found that the plants regained their normal growth after stopping dosing KNO3. So, why to add more CO2? BTW, people speculated that NO3 caused stunted tips, but they could never explain why adding more CO2 would help to alleviate the symptoms. Plants do need more energy and carbon in order to utilize NO3, hm, at least it seems to be a reasonable answer to me.

Regards,
Erich

 

[Tom Barr]

Well, I tried to find the answers. Many local hobbyists abandoned EI methods due to stunted tips or curling leaves esp. of Rotala macrandra, Alternanthera reineckii and Amannia gracillis etc. Crank up the CO2 more may help to resolve the problems. However many aquarists also found that the plants regained their normal growth after stopping dosing KNO3. So, why to add more CO2? BTW, people speculated that NO3 caused stunted tips, but they could never explain why adding more CO2 would help to alleviate the symptoms. Plants do need more energy and carbon in order to utilize NO3, hm, at least it seems to be a reasonable answer to me.

Regards,
Erich

Many like what THEY FIND, and do not like it when someone else comes along and proves that it was not true after all, rather, there was an alternative explanation that is the correct explanation.

I add 15ppm 3x a week of KNO3 to 4 tanks, never...have I had any issues.
Tonia, Erios, P stellata, A reineckii(And I'm not the only one here)

When you make a hypothesis, it must hold true for both cases.
So their hypothesis must be rejected, there is no debate about it, those are the observed facts.

We add NO3 to 20-30ppm without any issues.
No stunted tips of any sort.

A single paper for a single species, and............I bet you a nickel they do not know how much 500umols of NO3 is............in ppm's, and the sediment issues, there was also no fish in the study(something and a source of NH4 that most all aqurist do have BTW).....it really does not tell you that much, it might suspect........but if you test it, then many others have for many years.........

Then you have failed, not the EI...............

There has to be some other cause besides NO3, or nutrients.
People love to blame nutrients for their woes, yet few farmers do unless it's not enough nutrients.

I've read this same observation form a few groups here and there.
However, they are come and go.
They all seem to say "Me too!" and like a Mob, a new myth is born.

Then they go looking for facts that support their conclusions
That's dangerous.

BTW, they have stated similar claims about excess K+ doing this also
Some pretty scapers and a group of "me too's" all hopped on board.

What's that tell you?

What occurs when you limit something more and more?

If you limit Fe, or K, or NO3, or PO4 individually, they all will affect the uptake of other nutrients. Now if you limit them mildly, then growth slows, but stunting does not occur.

This is about the B range in the graph, this would reduce CO2 demand.
But to many, they see "correlation" and assume it means cause.

That does not prove anything.

Adding something and seeing an effect does not mean the other parameters in the plant tank are independent.

The paper is very specific, and does not have fish, does show interactions between low level NH4 sources(eg ADA AS, MS........organic matter etc) and NO3, so it's not just non NO3 adapted plants.

Hardly a strong argument for their case, particularly when I KNOW their test in their aquariums was not independent of CO2 and other factors. They simply did NOT do that test.

Without doing that, they cannot say anything much. Thing is, they wanna base their entire ego's on that.

Regards,
Tom Barr

 

[Tom Barr]

Here's some pictures of tanks with EI and those plants:

James' tank:

Regards,
Tom Barr

 

[Tom Barr]

I guess some folks simply do not know how to grow those 3 species listed and are not humble enough to blame their own lack of horticultural skills?????

This person's A reineckii is from the UK, he uses EI pretty rich and has for some years:

In the lower right corner, there's some R mac, about 18" tall:

I saw the fry on the Discus's parent's skin in this tank last time I was there.
The Angel's are F1's now, never seen any other tank or habitat their entire lives.

High NO3 supposedly causes fish health issues as well
When are these critics going to give it up?

I might have some old A gracilius pics, that was the very same plant that some claimed high K+ causes the tips to get stunted(Gee why not just say all nutrients at high non limiting levels cause stunting rather than poor CO2???)

Regards,
Tom Barr

 

[Tom Barr]

Erik's old tank had a center of A gracilius.

Google Image Result for http://showcase.aquatic-gardeners.org/Img2001/600/96.jpg

Huge weedy plant, very CO2 demanding.

Why would plantshave all the same CO2 demands?
Is it reasonable to assume that plants compete against eachother differentially in a very high density aquarium with high plant biomass?

Duuuhh.......

Of course.

So CO2 has to be non limiting as well as NO3, K+, PO4 etc..........to be sure that ALL SPECIES are being taken care of, not just a few.

These folks that have issues are just sloppy in their logic, follow up test, and likely do not care if whatever they do solves their issue. Nothign wrong with usign another method to solve the issue...however saying that it's NO3 is not right and they have not even bothered to test it.

That's the real issue here.
BTW, Erik had around 100-120ppm of K+ or so in the tank above.

Google Image Result for http://showcase.aquatic-gardeners.org/Img2001/600/96.jpg

Quite a few others dosing those ppm's have a similar look.

So with this evidence, how is it that others do not have the same issues?

Must be something other than NO3 alone causing their issues.

Regards,
Tom Barr


Regards,
Tom Barr


Regards,
Tom Barr

 

[jazzlvr123]

I dose EI pretty heavily en-fact I dose TWICE the recommended amount of Nitrates EI calls for, for my size tank (due to the fact that my ppms kept comig up short when i tested). I agree with tom its all about making nutrients available making sure there is no limiting factors to cause stunded/ curled leaves, carbon especially. I think its easy for people get caught up with nutrients and fail to take a step back and look at the bigger picture. Co2/ light/ how often you change your water/ how often (aggressive) you prune.

Heres an old pic of the rotala macrandra in my tank with VERY high Nitrate Dosage (no problems here )

 

[Tom Barr]

This is often the thought process illustrated by a cartoon:

There are many examples..........

K+ causing stunting was a classic one.
Someone found a reference to Ca++ signaling and K+ inhibition.

However, this was molecular communication signaling, not a reduction of growth rate.

When misapplied, not considered in the broader picture, not applied specifically to your specific situation (aquariums with, without CO2, fish, different sediment types etc) many use references. Does not mean they support their claim.
You'll note, we look at facts and see what conclusions we can safely draw from them.
Then we set up a test to see if say, NO3 is stunting these species in our aquariums.
If you have no reference for a control in your experiment, you simply have no idea if that conclusion is or is not correct, all you have is some correlation. You have no way to test if the other factors are independent of the result/s.
You have no way to test or see if there is some other alternative explanation.

That is sloppy and leaves you wide open for making huge mistakes.
This is not inherent in the average hobbyists, folks with PhD's make these same unwitting mistakes.

Paul Sears of the PMDD fame along with Kevin are really smart folks.
However, they did the same thing. They did not test their own hypothesis and check to see if there was some other factor causing algae.

You have to test and check the other alternatives.
Just because you personally came up with inconclusive evidence, does not mean you had everything independent either.
Many aquarist seem to think so. They for whatever reason, make a mistake(but assume they have not) and can not have the same success or are unable to reproduce it, yet many others can, they know they are adding say 20ppm or NO3.
At some point, you must accept you have done something wrong as others are adding it, and not having the same results.
That is a clear sign that there is something other factor you have over looked.

The above reference with P alpinius may support inert sand+NO3 at high levels in a non CO2 situation, without fish, NH4 or a combo of both NO3+ NH4 is superior for growth...........I do NOT argue that. But generalizing further while ignoring the observations that the rest of the aquarist have(are we all lying?) for the specific cases with.........high NO3, with CO2, with fish, with a wide range of sediments???

Then it becomes another matter entirely.
Then you are being selective with your logic and reference

It has to start with observations from many people, where we can know we have a certain non limiting upper bound for a nutrient. Not just a guess.

That is the control reference to base the test on and the standard that must be applied. Maybe no one has been able to grow A reineckii, A gracilius, or R macrandra in aquariums at higher NO3(No available observations for a control reference). However, for this case, such hypothesis has been falsified already and there's a long history of it.

So it cannot be correct for those species.
Either that, or we are all in a huge conspiratorial lie.

Not likely.

Regards,
Tom Barr

 

[paludarium]

Hi Tom,

thanks for the explicit replies. Personally I had very positive experience with EI methods. Unfortunately when folks encountered difficulties, they always blamed the nonlimiting nutrients, and they tried to solve the problems by reducing the dosages along with water changes but not adding more CO2. Therefore not surprising some hobbyists are becoming more conservative in their dosing routines.

I exactly know there are always controls and variables in a study, and the results can only be applied very cautiously. "Uptake, reallocation and reduction of NO3 by plants have a much higher energy and carbon requirement than NH4 uptake and assimilation" were cited by the authors from two references, which were both textbooks(?). I'm no botanist, don't have a chance to read them. I'm not sure if the above statement is correct, but I trust you, Tom.

Regards,
Erich

 

[Tom Barr]

Hi Tom,

thanks for the explicit replies. Personally I had very positive experience with EI methods. Unfortunately when folks encountered difficulties, they always blamed the nonlimiting nutrients, and they tried to solve the problems by reducing the dosages along with water changes but not adding more CO2. Therefore not surprising some hobbyists are becoming more conservative in their dosing routines.

Hi, I am well aware of your experience and position/s.
However, the reason why I am giving detailed info is to help you or others counter such "backwoods" thinking.

The same pattern has occurred, yet we KNOW that is not the problem with EI or ANY dosing method, after all, every single method of dosing nutrients has problems with at least few users, they all have issues.

This demonstrates that it is not nutrients directly causing the problem.
If limiting nutrients works so well and was the causing, we'd have to see it with EI.

Simply because they could not do a method correct, they look for causes, reasons to blame. They look for what they want to hear and sounds nice, not what the facts suggest.

I exactly know there are always controls and variables in a study, and the results can only be applied very cautiously. "Uptake, reallocation and reduction of NO3 by plants have a much higher energy and carbon requirement than NH4 uptake and assimilation" were cited by the authors from two references, which were both textbooks(?). I'm no botanist, don't have a chance to read them. I'm not sure if the above statement is correct, but I trust you, Tom.

Well, for that plant, there is a fair amount more energy requirement, but aquatic plants have lots of that and growth like.....well........weeds. If it reduces the growth rates a little bit (the evidence suggest that actual difference is pretty small, while significant for a wide range of plants, but this is only when 100% of N comes from NO3 in some species, others actually do better with NO3, depends on the species), and the trade off is a much better situation for fish, us, dosing etc.

It's not a cause for algae, which..........is an entirely different issue and should not be included.

This is a plant issue, I always wonder why people muddle algae control and nutrients together. I think keeping them separate and focusing on one issue at a time is much wiser.

And with good plant growth, there is really no algae issue.

Regards,
Erich

Regards,
Tom Barr