Phosphorus starvation and nitrogen?

[Belgian Anthias]

This has certainly been my experience; I've never seen high nitrates with low phosphates, only the opposite.

This seems logic in a system with a high anaerobic remineralization rate as the end products of anaerobic remineralization, denitrification and DNRA, will be NH3, N2, CO2, and phosphate of which CO2 and N2 may leave the system.
For a lot of reefers, this situation seems not to be the case.

 

[Belgian Anthias]

If nitrate is removed by assimilation, phosphorus and all other essentials are removed, which can continue till one of the essential building materials is used up. By nitrate assimilation, ammonia ( and nitrite) is leaked into the water promoting increased growth of r-strategists.
If nitrate is added as a nitrogen source on a regular base to a closed system it seems to me it may be important to know how it will be used.
May the evolution of the phosphate level tell the nitrogen manager what is happening?

 

[Nano sapiens]

This has certainly been my experience; I've never seen high nitrates with low phosphates, only the opposite.

The opposite is quite common, too, as seen in many threads. I've had .05 ppm PO4 and 50+ ppm NO3.

 

[Belgian Anthias]

Feldman and Maers concluded that skimmers remove max +- 35% of TOC . During the test, also bacteria were not able to remove most TOC. TOC built up with or without a skimmer.
Skimmers can only remove what bubbles trap, and bubbles only trap molecules and/or particles (i.e., bacteria, diatoms, etc.) with some compelling thermodynamic reason to adhere to the bubble's surface. On the molecular level, this surface association is typically driven by the molecule/particle having a hydrophobic (= water hating) patch that can be buried in the bubble surface/interior. This arrangement avoids the energetically penalizing juxtaposition of hydrophobic surfaces with (hydrophilic) water, and so overall the system energy is lowered (a favorable occurrence). Some of the molecules/particles in aquarium water will meet this hydrophobic region criterion, and some will not.(FeldmanEnMaers2010)
Results confirm that phosphorus is removed by the skimmer as it is found present in the beaker in much higher concentrations as might be expected.

Is there a difference in Nitrogen and or phosphorus content between hydrophobic and hydrophilic TOC?

Why bacteria can not use up most TOC?

 

[Randy Holmes-Farley Verified Community Expert]

Bacteria can use most toc found in a reef tank, but not all. Less common organics will take unusual species or strains to metabolize them. Maybe rare in reefs. In the ocean, large organic molecules get munched on until there’s no common biological route for further metabolism and further breakdown requires some Abiotic Uv or oxidation assistance. So what accumulates is less and less palatable to microbes.

The same probably happened in reef tanks, but there are some unnatural inputs (e.g. silicone oils, petroleum grease, etc) that won’t break down.

P is nearly always in very hydrophilic forms in seawater, but many P containing molecules are easily skimmed (such as a phospholipid). N can be in hydrophilic or hydrophobic forms, but much more often hydrophilic. Some are skimmable and some not.

there’s no accurate way to generalize about N and P -containing organics and extent of skimming.

many molecules are skimmed out as part of whole organisms such as bacteria or diatoms.

 

[Belgian Anthias]

Phosphorus starvation, what is it? Is it not be able to breathe?

If there is not enough available for growth one just has to wait but also while waiting energy is needed.
All cells store organics to be used to provide energy by making ATP, from glucose.
Cell respiration needs a form of phosphorus to activate the first step which is Glycolysis, sugar splitting.
Adenosine triphosphate (ATP) is a complex organic chemical that provides energy to drive many processes in living cells.
For to make enough ATP (C10H16N5O13P3), NAD ( ‎C21H27N7O14P2) and FAD (C27H33N9O15P2) are needed.

The N/P ratio is 5/3, 7/2 and 9/2 which means a lot more phosphorus is needed in relation to nitrogen compared to the ratios needed for growth.
It seems respiration needs another N/P ratio as cell synthesis.

During periods of increased growth, bacteria grow at a log rate, which means each cell division the demand is doubled, a lot of nitrogen is needed compared to phosphorus to build up the cells, the same time more energy must be provided and to form ATP at least an N/P ratio of 5/3 is needed. Translated to nitrate and phosphate in mg/l, this is about 1/1

 

[Belgian Anthias]

Detritus is TOC wich can not be remineralized in the present conditions!?
TOC present in aquaria may still contain a lot of DOC.
High DOC availability may be considered to have a bad influence on the coral holobiont as the ability of corals to manage their nutrient supply depends of their ability to manage the organic carbon and phosphorus availability for the holobiont. When usable DOC is always present there is nothing to manage.
As a skimmer does remove DOC very selective it would be interesting to know why not most that is left over is not remineralized.
TOC can be used as a food source.

 

[Belgian Anthias]

Detritus is TOC wich can not be remineralized in the present conditions!?
TOC present in aquaria may still contain a lot of DOC.
High DOC availability may be considered to have a bad influence on the coral holobiont as the ability of corals to manage their nutrient supply depends of their ability to manage the organic carbon and phosphorus availability for the holobiont. When usable DOC is always present there is nothing to manage.
As a skimmer does remove DOC very selective it would be interesting to know why not most that is left over is not remineralized.
TOC can be used as a food source.

I could not finish before time out.

Detritus is TOC wich can not be remineralized in the present conditions. In nature, not much TOC reaches the bottom of the ocean.
TOC present in aquaria may still contain a lot of DOC.
High DOC availability may be considered to have a bad influence on the coral holobiont as the ability of corals to manage their nutrient supply depends on their ability to manage the organic carbon availability and provide phosphorus for the holobiont. When usable DOC is always present, which may not easily be avoided in a closed system, there is nothing to manage and the corals may not be able to provide supplemental phosphorus when needed. ( phosphorus starvation?) In oligotrophic waters, Coral mucus contains about 116x the phosphorus content present in the surrounding waters.
As a skimmer does remove DOC very selective and leaves most hydrophilic and polar DOC behind, it would be interesting to know why not most DOC that is leftover is remineralized.

There are only two essential sulfur amino-acids, the one seems to be hydrophilic, the other hydrophobic.
May one consider most DOC left over to be polar? In what way this may influence the natural balance?

Short time use of a skimmer did not show any difference between the amount of TOC left over, with or without a skimmer which means the bacteria were able to replace the skimmer, TOC did not build up. At long term use of a skimmer, TOC builds up slowly which makes me conclude the use of the skimmer influences the growth rates of bacteria.

 

[Randy Holmes-Farley Verified Community Expert]

I’m not sure how to approach this thread. Are you trying to make a specific point? Should I point out statements that seem incorrect?

 

[SeaDweller]

This has certainly been my experience; I've never seen high nitrates with low phosphates, only the opposite.

I'm uncertain what you mean when you say you've never seen high N with low P? I've seen tanks 25-50 ppm NO3 and 0.03-0.10 ppm PO4, is that what you're referring to?

 

[Belgian Anthias]

I’m not sure how to approach this thread. Are you trying to make a specific point? Should I point out statements that seem incorrect?

Maybe this thread is posted in the wrong section, it is not directed to you personally.

It is about active system management. About knowing and having control. A critical look to generally accepted rules and procedures in reefing.

Since decades reefers battle nitrogen and phosphorus because both are considered to be harmful. Both often are blamed for anything that may go wrong.
For decades nitrate and phosphate are connected to coral health and growth. Of course both are connected, but will a high availability of phosphate and or nitrate be harmful to corals? After decades, phosphate and or nitrate levels are still part of discussions like in this one. Trying to add the why and the how. All help and critics are welcome.

 

[Belgian Anthias]

Both nitrate and or phosphate content are easily actively managed. Can this be done without thinking about possible consequences? And what may they be?

It may all start with the question: May an increased nitrate and or phosphate level, measured in a closed system, be held responsible, or is what has been measured the result of what is or was going on? In practice, the question is rarely asked.
Will battling nitrate and phosphorus help or just increase a problem or cause others? Thus the method used to battle the messenger matter?

Most advice given on fora concerning nitrate and or phosphate levels may be about battling the messengers.

It is known phosphor starvation causes coral bleaching but how this can be translated to what can be measured in an aquarium?
What is the link between DOC and available nitrogen and or phosphorus, as high DOC seems a lot more important for coral health as nitrate or and phosphate?

An important implication of the coral holobiont model is that disrupting any one of the components may cause the whole community to collapse and lead to coral death. In order to test this hypothesis, several experiments have been performed exposing corals to different stressors and then looked at the changes in microbial dynamics and diversity, as well as coral pathology. Stresses were applied to different coral species in the presence and absence of antibiotics. The data showed that of the many commonly cited stressors of corals, organic carbon (OC) loading is the most problematic. Coral death induced by OC can be delayed with antibiotics. Additionally, OC loading causes the coral-associated microbial communities to grow much faster then normal. This strongly suggests that changes in the bacterial community, and not the stresses themselves, are responsible for coral mortality. (Kline et al. 2006, Kuntz et al. 2005). ref: https://coralandphage.org/research_coral.php http://www.baharini.eu/baharini/doku.php?id=nl:makazi:theorie:koraal_holoboint

Also coral bleaching may cause mortality.

In this threat, the discussion is started about phosphorus starvation, found to be a cause of coral bleaching. How we can minimize the risks, now and in the future, without causing other and or bigger problems?
Most corals seem to be able to recover from bleaching, also in captivity.

 

[Randy Holmes-Farley Verified Community Expert]

This is a fine forum for an N/P ratio discussion.

I think you are trying to determine from first principles what every reefer sees for themselves in their tanks: the amount of N and P that accumulates or is needed to be dosed. I'm not sure the first principles approach will add to our understanding, but there's nothing wrong with speculating, as long as the speculations are sensible.

Phosphorus starvation, what is it? Is it not be able to breathe?

If there is not enough available for growth one just has to wait but also while waiting energy is needed.
All cells store organics to be used to provide energy by making ATP, from glucose.
Cell respiration needs a form of phosphorus to activate the first step which is Glycolysis, sugar splitting.
Adenosine triphosphate (ATP) is a complex organic chemical that provides energy to drive many processes in living cells.
For to make enough ATP (C10H16N5O13P3), NAD ( ‎C21H27N7O14P2) and FAD (C27H33N9O15P2) are needed.

The N/P ratio is 5/3, 7/2 and 9/2 which means a lot more phosphorus is needed in relation to nitrogen compared to the ratios needed for growth.
It seems respiration needs another N/P ratio as cell synthesis.

During periods of increased growth, bacteria grow at a log rate, which means each cell division the demand is doubled, a lot of nitrogen is needed compared to phosphorus to build up the cells, the same time more energy must be provided and to form ATP at least an N/P ratio of 5/3 is needed. Translated to nitrate and phosphate in mg/l, this is about 1/1

Let's address this section of yours, if you want.

P is not lost or gained when ATP is made from ADP, nor when it is consumed back to ADP.

ADP + Pi + energy ----> ATP
ATP ----> ADP + energy + Pi

These processes are internal to the organism, it does not release phosphate nor require new phosphate from outside the organism.

Thus, the cycling of ATP and ADP has no bearing on the consumption ratio of N and P.

 

[taricha]

in a system with a high anaerobic remineralization rate as the end products of anaerobic remineralization, denitrification and DNRA, will be NH3, N2, CO2, and phosphate of which CO2 and N2 may leave the system.

Are we saying that a large old sand bed with many organics in it that work their way down to anaerobic zones would push a system to be low in nitrate relative to phosphate?
Contrasted with a bare bottom tank with much less material in anaerobic zones would produce relatively more nitrate vs phosphate?

(Not personally well versed in the differences between the aerobic/anaerobic end products)

 

[Nano sapiens]

Are we saying that a large old sand bed with many organics in it that work their way down to anaerobic zones would push a system to be low in nitrate relative to phosphate?
Contrasted with a bare bottom tank with much less material in anaerobic zones would produce relatively more nitrate vs phosphate?

(Not personally well versed in the differences between the aerobic/anaerobic end products)

Speaking of phosphate to nitrate ratios, do reef aquaria that use Kalkwasser have, typically, lower PO4 to NO3 ratios in the water column due to precipitation of PO4? This has been the case in my small 'unfiltered' system for 11+ years (PO4 = undetectable/barely detectable, NO3 = ~5-10 ppm).

From what I've read and experienced there are many factors that can determine a system's phosphate to nitrate ratio. Based on personal experience over the decades with various ratios resulting in good results, I don't believe that a 'magic ratio' exists, but that extremes are to be avoided.

 

[Belgian Anthias]

This is a fine forum for an N/P ratio discussion.

I think you are trying to determine from first principles what every reefer sees for themselves in their tanks: the amount of N and P that accumulates or is needed to be dosed. I'm not sure the first principles approach will add to our understanding, but there's nothing wrong with speculating, as long as the speculations are sensible.



Let's address this section of yours, if you want.

P is not lost or gained when ATP is made from ADP, nor when it is consumed back to ADP.

ADP + Pi + energy ----> ATP
ATP ----> ADP + energy + Pi

These processes are internal to the organism, it does not release phosphate nor require new phosphate from outside the organism.

Thus, the cycling of ATP and ADP has no bearing on the consumption ratio of N and P.

Within the cell, as it is the intention to use the ATP for energy. But when growing at a log rate each produced cell has to breathe, needing also C, N and P for cell respiration, to build up enough NAD , FAD , ADP and ATP to become the energy to build up biomass, multiply and respire. The P to start the internal cycle must be available. Respiration starts with glucose, N and P must be added to be able to form ATP which needs a 5/3 N/P ratio, retrieved at a log rate.
The N and P for the respiration of bacteria in log phase, high growth, must come from somewhere, influencing the consumption ratios.
If we talk about C/N/P ratio's ( Redfield) needed to build up bio-mass, thus this includes what is needed for to make respiration possible?


How does a reefer see what is needed to be dosed or removed? We measure what is present at the moment, what is left over. Phosphorus starvation, or other nutrient starvation, does not only depend on what is generally measured in the water column of a reef aquarium! The results of standard tests taken when something is visually wrong do not represent what caused the problem but are the result. Measuring N/P on a dying reef and then blaming the results to be the cause of death is not a good approach for determining what may have caused the problem.

Asking questions may be speculative if one expects a certain answer. Sometimes one speculates about the right question to ask to find answers.
A lot of methods and procedures used in managing reef aquaria are speculative, based on assumptions. Reefers have satisfactory results, others are not reefers any more, others were not able to become a reefer, despite having followed standard and generally accepted rules, methods, and advice. Why? We are keeping reef aquaria for decades!!! Maybe there is something wrong with the methods and standards used, and this is not a purely speculative question?

 

[EMeyer]

I'm uncertain what you mean when you say you've never seen high N with low P? I've seen tanks 25-50 ppm NO3 and 0.03-0.10 ppm PO4, is that what you're referring to?

I mean I've never seen a tank with stats like you describe. I'm not denying they exist - I have no reason to doubt other people's numbers. Just saying I've run a bunch of tanks (currently operating 16 systems) and never seen this situation. I always see low NO3 (<5, usually <2) unless I specifically dose NO3. But PO4 accumulation, I see. So high PO4, low NO3 is a common situation I've seen, while high NO3, low PO4 is a situation I've never seen.

Not doubting other peoples' experience, just saying its not a common situation IME.

 

[taricha]

do reef aquaria that use Kalkwasser have, typically, lower PO4 to NO3 ratios in the water column due to precipitation of PO4? This has been the case in my small 'unfiltered' system for 11+ years (PO4 = undetectable/barely detectable, NO3 = ~5-10 ppm).

I switched from 2 part to kalk, and noticed no difference in N/P behavior. But I run my kalk way below levels where precipitation could occur (dkh under 8) so I'm not a good candidate to see that effect.

 

[SeaDweller]

I mean I've never seen a tank with stats like you describe. I'm not denying they exist - I have no reason to doubt other people's numbers. Just saying I've run a bunch of tanks (currently operating 16 systems) and never seen this situation. I always see low NO3 (<5, usually <2) unless I specifically dose NO3. But PO4 accumulation, I see. So high PO4, low NO3 is a common situation I've seen, while high NO3, low PO4 is a situation I've never seen.

Not doubting other peoples' experience, just saying its not a common situation IME.

If I didnt run Rowaphos I’d probably be in the low N and high P camp. i feed flakes and pellets heavily and frozen at night, so that’s probably why. A buddy of mine who skims and doesn’t use a fuge or gfo feeds frozen that he mixes exclusively and it’s high N and naturally low P for him. Interesting.

 

[Randy Holmes-Farley Verified Community Expert]

If we talk about C/N/P ratio's ( Redfield) needed to build up bio-mass, thus this includes what is needed for to make respiration possible?

Of course, but you cannot pick out some selected processes and suggest that means something significant for the required N/P ratio to grow.

I can list hundreds of molecules that contain N, P or both, that are needed to build tissue. Thinking about what they are makes no sense since we have no idea on the exact numbers of each. The only thing that makes sense to understand the relative amounts of N and P required for growth is to either analyze whole organisms for N and P, or study what they take up as they grow.