Nitrate- cannot get it to fall

[JonasRoman]

I am missing the combined application of nitrate and ammonium very much in the article since this is the normal condition we have in tanks. With both N forms present the ammonium may be the N compound mainly assimilated and in this way nitrate possibly has no chance to get detrimental.

It was flushed with water from ocean meaning a natural level and supply of ammonium was there all time, if I understand it correct.
Actually its more interesting to isolate and exaggerating the situation as the question is what nitrate specifically do with a coral. If you mask that with the a dose of forgiveness ammonium the question will not be possible to answer. Then we only may answer if its a true problem. Here its more to find out what a single substance may do with the metabolism. Then its up to you to choose if you want to rely on protection mechanism or just try to also minimise the bad agents. Same in human medicine, (my profession): we can give something that gives ulcus in stomach, like Trombyl. But with omeprazol we can hide the bad effects. So a study of trombyls bad effect with concomitant addition of omeprazol will hide the knowledge what trombyl may cause.
So, I think this study design is excellent.

 

[Hans-Werner]

It hasn't even factored in that NO₃ isn't the only N source and PO₄ the only P source. So obviously precise N:P ratios are far to complex for hobbyists to measure.

This statement is at least misundestandable if not wrong, depending on how it is meant. As far as I know corals can also assimilate phosphonates, but in general phosphate (different ions, depending on pH, actual PO4--- is only formed at very high pH) is the P taken up almost exclusively. Also there are simply no much other phosphorus forms available under the conditions corals and most other organisms live. There are polyphosphates and organic phosphates, but they are still phosphates, and they are generally only taken up after hydrolysis to orthophosphate, for example after splitting by enzymes like alkalinic phosphatase.

 

[EnterName]

It hasn't even factored in that NO₃ isn't the only N source and PO₄ the only P source. So obviously precise N:P ratios are far to complex for hobbyists to measure.

This statement is at least misundestandable if not wrong, depending on how it is meant. As far as I know corals can also assimilate phosphonates, but in general phosphate (different ions, depending on pH, actual PO4--- is only formed at very high pH) is the P taken up almost exclusively. Also there are simply no much other phosphorus forms available under the conditions corals and most other organisms live. There are polyphosphates and organic phosphates, but they are still phosphates, and they are generally only taken up after hydrolysis to orthophosphate, for example after splitting by enzymes like alkalinic phosphatase.

Fair point, I definitely should have worded that differently and will make a small edit below my original comment to hint towards your correction.

I was referring to Orthophosphate which our hobby-grade tests can detect. Just recently you posted how you might even prefer ICP P results because it reflects other non-detectable (by hobby test-kits) phosphorus sources (even if they are also phosphates). So phosphorus might have been the better word.

Either way, when you look at the comments further in the discussion Dan_P pointed out the insufficient precision of test kits to get a reliable N:P ratio and even if we only care for the detectable nitrate and phosphate sources this held true which I have shown mathematically using the available accuracy measures of Hanna Instruments.

 

[Hans-Werner]

It was flushed with water from ocean meaning a natural level and supply of ammonium was there all time, if I understand it correct.
Actually its more interesting to isolate and exaggerating the situation as the question is what nitrate specifically do with a coral. If you mask that with the a dose of forgiveness ammonium the question will not be possible to answer. Then we only may answer if its a true problem. Here its more to find out what a single substance may do with the metabolism. Then its up to you to choose if you want to rely on protection mechanism or just try to also minimise the bad agents. Same in human medicine, (my profession): we can give something that gives ulcus in stomach, like Trombyl. But with omeprazol we can hide the bad effects. So a study of trombyls bad effect with concomitant addition of omeprazol will hide the knowledge what trombyl may cause.
So, I think this study design is better to not add unnatural amounts of ammonium at same time.

I disagree, a fourth design with 1.5 µM nitrate and 1.5 µM ammonium would have been perfect. It wouldn't have lessened the value of the other results.

The phosphate concentration:

"(1) control condition (control), with natural seawater (ca. 0.5 μM DIN, 0.2 μM P);" (~ 0.02 ppm phosphate)

"In our experiments, a phosphate concentration of ~0.3 μM at a N:P ratio of 22:1 yielded an overall healthy phenotype. Accordingly, it is likely that the absolute N:P ratio becomes also less critical for the proper functioning of the symbionts when phosphate concentrations exceed a vital supply threshold (>0.3 μM), even when the symbionts are rapidly proliferating." (Rosset et al., 2017, §4.3)

 

[JonasRoman]

disagree, a fourth design with 1.5 µM Nitrate and 1.5 µM ammonium would have been perfect. It wouldn't have lessened the value of the other results.

It would have made it impossible to answer the end point question of the study which is what nitrate do with the coral. With your idea you may mascerade that findings and just get answer that if ammonium exist there is less damage. That reduces the power of the study AMO.
What you suggest is next study, how can we protect us from bad effects of nitrate ?

 

[ReneReef]

Just to clarify definitions of “chasing numbers”.

What do you think about @Lasse effort to keep the nitrate and phosphate down in his system with ethanol and GFO? Is that chasing numbers? Or should we consider that variations in chasing numbers exist, such as, informed v uninformed chasing numbers?

Aquarists can manage their aquarium quite differently and just maybe they have a system that is exquisitely sensitive to nitrate and phosphate concentration while others not so much. Maybe it is the age of the aquarium or what and how much they stock their aquarium.

Good point.
Too me the difference between chasing a number and keeping things in check is where a numbers becomes a goal in stead of our animals thriving.

I’ve had my tanks (lots of SPS) thrive at nitrates anywhere between 0 and 100.

So, lets leave out the word chasing: in my opinion there is currently no evidence that any fixed nitrate number is universally best.

 

[Hans-Werner]

Fair point, I definitely should have worded that differently and will make a small edit below my original comment to hint towards your correction.

I was referring to Orthophosphate which our hobby-grade tests can detect. Just recently you posted how you might even prefer ICP P results because it reflects other non-detectable (by hobby test-kits) phosphorus sources (even if they are also phosphates). So phosphorus might have been the better word.

Either way, when you look at the comments further in the discussion Dan_P pointed out the insufficient precision of test kits to get a reliable N:P ratio and even if we only care for the detectable nitrate and phosphate sources this held true which I have shown mathematically using the available accuracy measures of Hanna Instruments.

I agree, but even with perfect test kits we have to aknowledge the interactions of the different nutrients.

I just wanted to make clear that there are no "mysterious" forms of phosphorus as it is sometimes treated. There is orthophosphate, inorganic polyphosphates (storage form of phosphate in bacteria and microalgae) and organic phosphates, and maybe a very small amount of phosphonates. Nothing mysterious.

 

[Hans-Werner]

It would have made it impossible to answer the end point question of the study which is what nitrate do with the coral.

For this you don't need a run with ammonium either. Just nitrate and control would have been sufficient.

 

[JonasRoman]

There is orthophosphate, inorganic polyphosphate (storage form of phosphate in bacteria and microalgae) and organic phosphate, and

Exactly, and here I take opportunity to mention a subject that is relevant: total P is actually quite often significant higher than true po4. Especially as p is such low concentration small difference in inorganic/organic gives a % big difference.
I do often inorganic po4 measurements, like twice a day with my photometer (Mastertronic E) (and double checked with icp labs photometer aswell) and compare these regularly with icp calculated po4. Difference between these is same as organic P, and surprisingly its something 100% diff between inorganic true po4 and icp oes calculated po4.
Last test, and examples my message:
Icp calculated "po4" : 0.08 ppm
True po4 (photometry): 0.03 ppm
So 0.05 ppm ppo4 is not po4 but organic P. So actually the situation here was
Po4 : 0.03 ppm
Organic bound P: 0.016 ppm ((0.08-0.05)/3))

Jonas

 

[JonasRoman]

For this you don't need a run with ammonium either. Just nitrate and control would have been sufficient.

Ofcourse but the single addition of ammonium give us further info and open up a new study like the one you suggest.

 

[ReneReef]

So now you are telling us your opinion as a fact. So we simply disagree. And I have explained why. Its ok to have different views, that's why we discuss. Now I know you have another opinion than me and you have no arguments that convincing me. Its also OK. Ofcourse no one shall follow any one. We do what we believe in. With same purpose.

I am reluctant to discuss the permissions to have views like you did instead of the subject itself. Its waste of time.

Jonas

You formulate your opinion as a commandment “we shall”.
The burden of proof to support such a strong statement is yours.

I clearly state when something is my opinion and I don’t preach others shall follow it.

If you want people to blindly follow your commandments or opinions or whatever, start a cult

P.S. you seem to have abandoned this discussion of the same paper https://www.reef2reef.com/threads/nitrate-increase-oxidative-stress.1171328/

 

[areefer01]

You are presenting your opinion as fact or some universal truth again. Its not.

I consider “chasing” N and P the least important. Yes, many traces too, but that is no argument in this discussion.

Nitrate and phosphate are factors with limited meaning in the entirety of N and P. And truly good home tests actually don’t exist. As discussed and demonstrated previously in this topic, they should even be considered terrible when it comes to providing a ratio. Even if that was of any use at all.

So, shall I follow your commandments?
No.

If they don't exist then why are we even having this discussion? Are they only good enough to support ones point of view? They are the tools available to traditional hobbyist.

 

[EnterName]

Fair point, I definitely should have worded that differently and will make a small edit below my original comment to hint towards your correction.

I was referring to Orthophosphate which our hobby-grade tests can detect. Just recently you posted how you might even prefer ICP P results because it reflects other non-detectable (by hobby test-kits) phosphorus sources (even if they are also phosphates). So phosphorus might have been the better word.

Either way, when you look at the comments further in the discussion Dan_P pointed out the insufficient precision of test kits to get a reliable N:P ratio and even if we only care for the detectable nitrate and phosphate sources this held true which I have shown mathematically using the available accuracy measures of Hanna Instruments.

I agree, but even with perfect test kits we have to aknowledge the interactions of the different nutrients.

I just wanted to make clear that there are no "mysterious" forms of phosphorus as it is sometimes treated. There is orthophosphate, inorganic polyphosphate (storage form of phosphate in bacteria and microalgae) and organic phosphate, and maybe a very small amount of phosphonates. Nothing mysterious.

Yes, I think this also was part of Dan_P's initial comment that prompted me to make the admittedly flawed response. I certainly didn't want to make phosphorus sound more mysterious than it is

Anyway, if you have looked through this thread a little bit you might have noticed that there are different opinions about the importance of N:P ratios in reef tanks.

A: Some say ratios are nothing we should worry about. Absolute levels are enough or at least the best we can do due to the limited test precision we have access to. Nitrogen and phosphorus sources aren't perfect and don't detect all available N and P so we can't measure a perfect ratio anyway.

B: Others say no matter the nutrient levels, we should keep an eye on the ratio between N and P or at least nitrate and phosphates our tests detect.

C: Then there is the option that ratios usually matter, but only until a certain threshold of available phosphate is reached and from there the ratio might become less critical for coral health.

What's your take on the issue, if I may ask?

 

[JonasRoman]

You formulate your opinion as a commandment “we shall”.
The burden of proof to support such a strong statement is yours.

I clearly state when something is my opinion and I don’t preach others shall follow it.

If you want people to blindly follow your commandments or opinions or whatever, start a cult

Thats a total misunderstanding and oversensitive reaction from your side. I think we are all on that level here we understand that no one tells anyone what you "shall" do. On the contrary, I like disagreement, that gives us a good discussion.
Like I said to a student yesterday "please tell me I am wrong, because then I maybe can learn something also today"

 

[ReneReef]

If they don't exist then why are we even having this discussion? Are they only good enough to support ones point of view? They are the tools available to traditional hobbyist.

Good question.

Yes, they are the tools available and no I don’t think they are useless. However, they are crude instruments and I think we often put too much value in the exact numbers show.

 

[JonasRoman]

If they don't exist then why are we even having this discussion? Are they only good enough to support ones point of view? They are the tools available to traditional hobbyist.

Good point. And my view of this, of ofcourse they are good enough. Because ratios and absolute values are not that superfixed. We can learn a lot from those N and P tests we do at home.

 

[Hans-Werner]

Since it was one of the heavily discussed points here, I just want to underline and repeat one statement that may have got lost in the latest discussion, and I think you really should keep this in mind:

Water nutrient ratios and cellular nutrient ratios are two completely different things. The one can never be translated into the other, at least not without excellent knowledge of the concentrations and the uptake kinetics for the different nutrients of the organism you want to investigate. Since different ion pumps for nutrient uptake have different uptake kinetics, water nutrient ratios will never translate into the same cellular nutrient ratios. Treating it "as if" is an absolute mistake. Nutrients will never be depleted really to zero. There will always be a concentration when nutrient uptake stops, becomes net zero. If the water concentration is almost there, there will be not much uptake of this nutrient. With phosphate this may be the case at low natural phosphate concentrations.

 

[Hans-Werner]

Icp calculated "po4" : 0.08 ppm
True po4 (photometry): 0.03 ppm
So 0.05 ppm ppo4 is not po4 but organic P. So actually the situation here was
Po4 : 0.03 ppm
Organic bound P: 0.016 ppm ((0.08-0.05)/3))

There are no "true" and "false" phosphates, just orthophosphate and so on, I have commented on this here already.

What's your take on the issue, if I may ask?

C is my opinion, but with the limitation just mentioned above. The closer you get to the minimum uptake concentration, which may be around 0.02 ppm for phosphate in corals, the closer the N:P should get, up to the point that N:P could get 1:1 or maybe even 1:2 depending on the minimum uptake concentrations of the available N compounds.

I edited my first comment because I think the minimum uptake concentrations for available N compounds are not so much lower compared to phosphate, but a molar ratio of 1 : 1 is a realistic ratio I am quite sure, meaning a 1 : 1 water ratio may translate into a cellular 16 : 1 ratio because phosphate is at the minimum uptake concentration at 0.2 µM/L while in ammonium and some other N compounds it's not.

 

[BeanAnimal]

Just a comment concerning chasing numbers, N and P and others:
For N and P we shall definitely "chase" numbers as those 2 parameters are one of the most important.

I don't buy that the precise numbers are important at all, as long as each falls within an extremely broad acceptable range.

I do not think any particular ratio matters as long as neither N nor P is limiting and neither is at a known harmful level.

The flaw in many of these arguments is the assumption that assimilation is governed by the measured N:P ratio, and that “limitation” can result either from insufficient supply or simply from an excess of the other element. We know that insufficient availability can be limiting. An excess of one element does not, by itself, make the other limiting. Where is the research showing otherwise?

To that end, many people promoting “ratios” are using ppm instead of molar quantities, so the numbers they cite are not even the Redfield ratio or whatever other ratio they think they are promoting.

 

[Hans-Werner]

In supply and consumption certain nutrient ratios matter but not in water concentrations (standing stock of nutrients).

If we take the example of the Redfield ratio N:P 16:1 and you have for example a culture of plankton algae, it makes sense if the supply is also in the ratio 16:1 to create a steady state if you want to run a chemostat culture.

You may run a reef tank similar to a chemostat by creating a steady state of supply and consumption. Then the nutrient concentrations in your reef tank remain constant and, if you want, at low concentrations without getting limiting. Ratios of consumption in reef tanks will differ from the Redfield ratio.