Ammonium dosing is a bit overrated

[Dread Pirate Dave]

If one does find high iron in their system, what’s the best way to remove it that isn’t a water change?

Polly filter, perhaps? But it could remove stuff you want too.

 

[Vested]

I know that there are other opinions on iron.

In my experience there are no problems directly connected to iron dosing short-term. The problems are more long-term and are mainly problems with growth of cyanobacteria and nuisance algae like Valonia. Just as long-term as the problems develop you need to get rid of them. So, there is neither a short-term problem nor a short-term success, and it is not easy to connect cause and effect. It is the experience of decades of regular dosing and years of taking a closer look.

Thank you for the response, I think this is all useful information and I appreciate it! For what its worth I have also noticed increased cyano and bubble algae specifically on multiple different tanks increasing iron dosage over the last year. Like you said hard to pin-point cause and effect but seems like it. The more data the better even if antidotal! I think iron is extremely valuable to dose just not necessarily a number to shoot for readings on even with icp ms may be too much.

Your point about actually wanting to LIMIT zoox growth to an extent is very valid I believe.

 

[Hans-Werner]

If one does find high iron in their system, what’s the best way to remove it that isn’t a water change?

No water changes, just wait, with normal calcium and alkalinity additions. Iron is out of the water soon under typical reef tank pH and oxygen/ORP.

Following measures should further help lower iron concentrations:

- Coral growth and corresponding calcium and alkalinity dosing
- Moderately high or high phosphate concentrations, 0.1 ppm or higher
- Moderately high or high nitrate concentrations
- Manganese dosing, but possibly has negative side effects, maybe preferably manganese + other trace metals zinc, nickel, copper, cobalt.
- Algae filters and refugiums with green algae

These factors should increase iron precipitation and/or incorporation.

Some may have done this already inadvertendly.

Dissolved iron concentrations in the water may or may not be the main problem.

Hard corals seem to do better with low concentrations/low dosing of iron in the water.

For cyanobacteria and nuisance algae growth iron precipitates seem to be sufficient.

 

[Hans-Werner]

Your point about actually wanting to LIMIT zoox growth to an extent is very valid I believe.

Just in the last days I received a newsletter about a preprint of an article. This article and the cited literature say that zooxanthellate corals regulate the supply of nitrogen to their zooxanthellae by nitrogen fixation and denitrification, in this way keeping (or at least try to keep) zooxanthellae nitrogen limited.

So it may be a limitation by one of both, iron or nitrogen, or a colimitation by both.

There are more interesting statements about nitrogen nutrition of corals in this article. Well, and we are back at the main theme according to the headline.

 

[Vested]

Just in the last days I received a newsletter about a preprint of an article. This article and the cited literature say that zooxanthellate corals regulate the supply of nitrogen to their zooxanthellae by nitrogen fixation and denitrification, in this way keeping (or at least try to keep) zooxanthellae nitrogen limited.

So it may be a limitation by one of both, iron or nitrogen, or a colimitation by both.

There are more interesting statements about nitrogen nutrition of corals in this article. Well, and we are back at the main theme according to the headline.

Interesting!

 

[Dan Reef]

Just in the last days I received a newsletter about a preprint of an article. This article and the cited literature say that zooxanthellate corals regulate the supply of nitrogen to their zooxanthellae by nitrogen fixation and denitrification, in this way keeping (or at least try to keep) zooxanthellae nitrogen limited.

So it may be a limitation by one of both, iron or nitrogen, or a colimitation by both.

There are more interesting statements about nitrogen nutrition of corals in this article. Well, and we are back at the main theme according to the headline.

Does that include ammonia? I was “debating” about nitrogen with AI and it said that this regulation doesn’t apply to ammonia as it penetrates easily in the cell membranes. The result is that the coral lose the ability to control nitrogen access to zooxanthellae.

Here’s the AI summary of our “debate”:

Technical Summary: Passive Diffusion of Ammonia in Corals


In scleractinian (stony) corals, the host animal regulates the growth of its symbiotic algae (zooxanthellae) by strictly limiting their access to nitrogen. When you dose Nitrate (NO_3^-), the coral maintains control because nitrate requires active transport (energy-consuming proteins) to cross cell membranes.


However, Ammonia (NH_3) bypasses this "gatekeeper" mechanism through passive diffusion.


1. The Permeability of Membranes to NH_3


The uncharged, non-ionized form of ammonia (NH_3) is lipid-soluble. According to the literature, NH_3 diffuses directly through the lipid bilayer of the coral's cell membranes. Because the zooxanthellae constantly consume nitrogen, the internal concentration remains lower than the external water, creating a continuous "suction" of ammonia into the coral tissue that the animal cannot stop.


2. The High pH Factor


The ratio of NH_4^+ (ion) to NH_3 (gas) is pH-dependent. At your peak pH of 8.6, the concentration of the diffusing form (NH_3) is significantly higher than at standard pH levels. This floods the coral’s internal environment with nitrogen.


3. Metabolic Consequences


When the host loses control over the nitrogen supply, the zooxanthellae population explodes. This "over-fertilization" leads to:


• Browning: Excessive algal density masks the coral's natural pigments.


• Reduced Calcification: The symbionts begin to keep more carbon for their own division instead of "sharing" it with the host for skeleton building, explaining why KH consumption drops.


Key Scientific Literature


• Muscatine, L., & D’Elia, C. F. (1978). "The uptake and retention of ammonium in reef corals." * Key finding: Demonstrated that ammonium uptake is often a passive process driven by the high demand of the zooxanthellae, making the coral a "sink" for nitrogen.


• D’Elia, C. F., & Cook, C. B. (1988). "Methylamine uptake by zooxanthellae-invertebrate symbioses."


• Key finding: Discusses the diffusion of neutral molecules (like NH_3) across membranes and how it circumvents host control.


• Dubinsky, Z., et al. (1990). "The effect of external nutrient resources on the optical properties and photosynthetic efficiency of Stylophora pistillata."


• Key finding: Shows how high nitrogen levels lead to uncontrolled zooxanthellae growth, which actually reduces the efficiency of the coral-algal relationship.


• Yellowlees, D., Rees, T. A. V., & Leggat, W. (2008). "Metabolic interactions between algal symbionts and invertebrate hosts."


• Key finding: A definitive review explaining that while the host controls nitrate and phosphate via transporters, it has little control over the passive influx of ammonia.

 

[Randy Holmes-Farley]

Browning: Excessive algal density masks the coral's natural pigments.

• Reduced Calcification: The symbionts begin to keep more carbon for their own division instead of "sharing" it with the host for skeleton building, explaining why KH consumption drops.

I think this is a good reason to ignore AI conclusions. They can provide facts, but are bad at using them to extrapolate.

First, contrary to its claim that calcification is reduced at higher pH, it is extremely widely experienced in reef tanks that calcification increases at higher pH. It may (or may not) be the case this this particular ammonia mechanism causes a reduction, but the overall effect is the opposite of what your AI claims.

Second, there is no general evidence that higher pH causes apparent browning of corals, contrary to the AI claim.

 

[Hans-Werner]

Does that include ammonia? I was “debating” about nitrogen with AI and it said that this regulation doesn’t apply to ammonia as it penetrates easily in the cell membranes. The result is that the coral lose the ability to control nitrogen access to zooxanthellae.

Here’s the AI summary of our “debate”:

Technical Summary: Passive Diffusion of Ammonia in Corals


In scleractinian (stony) corals, the host animal regulates the growth of its symbiotic algae (zooxanthellae) by strictly limiting their access to nitrogen. When you dose Nitrate (NO_3^-), the coral maintains control because nitrate requires active transport (energy-consuming proteins) to cross cell membranes.


However, Ammonia (NH_3) bypasses this "gatekeeper" mechanism through passive diffusion.


1. The Permeability of Membranes to NH_3


The uncharged, non-ionized form of ammonia (NH_3) is lipid-soluble. According to the literature, NH_3 diffuses directly through the lipid bilayer of the coral's cell membranes. Because the zooxanthellae constantly consume nitrogen, the internal concentration remains lower than the external water, creating a continuous "suction" of ammonia into the coral tissue that the animal cannot stop.


2. The High pH Factor


The ratio of NH_4^+ (ion) to NH_3 (gas) is pH-dependent. At your peak pH of 8.6, the concentration of the diffusing form (NH_3) is significantly higher than at standard pH levels. This floods the coral’s internal environment with nitrogen.


3. Metabolic Consequences


When the host loses control over the nitrogen supply, the zooxanthellae population explodes. This "over-fertilization" leads to:


• Browning: Excessive algal density masks the coral's natural pigments.


• Reduced Calcification: The symbionts begin to keep more carbon for their own division instead of "sharing" it with the host for skeleton building, explaining why KH consumption drops.


Key Scientific Literature


• Muscatine, L., & D’Elia, C. F. (1978). "The uptake and retention of ammonium in reef corals." * Key finding: Demonstrated that ammonium uptake is often a passive process driven by the high demand of the zooxanthellae, making the coral a "sink" for nitrogen.


• D’Elia, C. F., & Cook, C. B. (1988). "Methylamine uptake by zooxanthellae-invertebrate symbioses."


• Key finding: Discusses the diffusion of neutral molecules (like NH_3) across membranes and how it circumvents host control.


• Dubinsky, Z., et al. (1990). "The effect of external nutrient resources on the optical properties and photosynthetic efficiency of Stylophora pistillata."


• Key finding: Shows how high nitrogen levels lead to uncontrolled zooxanthellae growth, which actually reduces the efficiency of the coral-algal relationship.


• Yellowlees, D., Rees, T. A. V., & Leggat, W. (2008). "Metabolic interactions between algal symbionts and invertebrate hosts."


• Key finding: A definitive review explaining that while the host controls nitrate and phosphate via transporters, it has little control over the passive influx of ammonia.

I don't think the AI is completely right here.

Depending on pH and Temperature a certain proportion of ammonium (NH4+) is deprotonized as ammonia (NH3) which is able to penetrate membranes - so far so right. How much of this ammonia is "available" of course depends also on total ammonium/ammonia concentration.

If this question is specific about nitrogen fixation, I can say that nitrogen fixation of bacteria stops when nitrogen (i. e. as ammonium or ammonia) is available.

When corals are nitrogen limited you will see a very rapid browning, in about a day, after dosing ammonium. This I can tell from own trials.

Ammonia and ammonium are involved in several processes in corals and the enzymes glutamin synthetase, glutamate dehydrogenase and urease are involved. At least urease is involved in coral calcification and releases ammonia, increasing the pH during calcification in this way. This means, calcification may also be a source for ammonium/ammonia. Ammonia release by glutamate dehydrogenase and ammonia binding by glutamin syntethase may even be a kind of proton shuttle mechanism to remove protons in coral calcification.

After the coral host has formed glutamin from ammonia and glutamate, the nitrogen is under control of the coral host. There may or may not be any direct transfer of ammonia from the environment to the zooxanthellae, depending on the extent and effectivity of ammonia binding by glutamin synthetase and glutamin formation in the coral host.

I think this process is not finally clarified by science. Nevertheless it seems a bit more complicated than the conclusions of the AI.

 

[Dan Reef]

I think this is a good reason to ignore AI conclusions. They can provide facts, but are bad at using them to extrapolate.

First, contrary to its claim that calcification is reduced at higher pH, it is extremely widely experienced in reef tanks that calcification increases at higher pH. It may (or may not) be the case this this particular ammonia mechanism causes a reduction, but the overall effect is the opposite of what your AI claims.

Second, there is no general evidence that higher pH causes apparent browning of corals, contrary to the AI claim.

Hi Randy,

I believe AI was referring to the increased zooxanthellae population and the use of the carbon produced instead of becoming available to the coral. It says that at a higher pH, more nitrogen from ammonia is available to zooxanthellae which can be good but also bad if it's too much.

 

[Dan Reef]

I don't think the AI is completely right here.

Depending on pH and Temperature a certain proportion of ammonium (NH4+) is deprotonized as ammonia (NH3) which is able to penetrate membranes - so far so right. How much of this ammonia is "available" of course depends also on total ammonium/ammonia concentration.

If this question is specific about nitrogen fixation, I can say that nitrogen fixation of bacteria stops when nitrogen (i. e. as ammonium or ammonia) is available.

When corals are nitrogen limited you will see a very rapid browning, in about a day, after dosing ammonium. This I can tell from own trials.

Ammonia and ammonium are involved in several processes in corals and the enzymes glutamin synthetase, glutamate dehydrogenase and urease are involved. At least urease is involved in coral calcification and releases ammonia, increasing the pH during calcification in this way. This means, calcification may also be a source for ammonium/ammonia. Ammonia release by glutamate dehydrogenase and ammonia binding by glutamin syntethase may even be a kind of proton shuttle mechanism to remove protons in coral calcification.

After the coral host has formed glutamin from ammonia and glutamate, the nitrogen is under control of the coral host. There may or may not be any direct transfer of ammonia from the environment to the zooxanthellae, depending on the extent and effectivity of ammonia binding by glutamin synthetase and glutamin formation in the coral host.

I think this process is not finally clarified by science. Nevertheless it seems a bit more complicated than the conclusions of the AI.

Would dose ammonia once a day be preferable instead of several times a day? Or maybe weekly? Since it's quickly consumed, by dosing all at once we would reduce the chance of being available in excess or during a long period to the zooxanthellae thus giving the coral the ability to control nitrogen availability. Same as a coral reef where food is available in pulse.

 

[Randy Holmes-Farley]

Hi Randy,

I believe AI was referring to the increased zooxanthellae population and the use of the carbon produced instead of becoming available to the coral. It says that at a higher pH, more nitrogen from ammonia is available to zooxanthellae which can be good but also bad if it's too much.

It's probably not useful to spend too much time focusing on why it said what it did, especially not knowing what it was asked, but its written conclusions do not seem to mesh with actual reefer experiences.

 

[Hans-Werner]

Would dose ammonia once a day be preferable instead of several times a day? Or maybe weekly? Since it's quickly consumed, by dosing all at once we would reduce the chance of being available in excess or during a long period to the zooxanthellae thus giving the coral the ability to control nitrogen availability. Same as a coral reef where food is available in pulse.

There is one quite new article saying that in Acropora intermedia from the Australian GBR nutrient pulses clearly had better effects on coral condition than continuously increased nutrient concentrations, labeled "press" in the article.

Overall the condition of corals was much more balanced and similar to the control corals (red pentagon in Fig. 3) in the pulsed application (black pentagon in Fig. 3) than in the continuous applications of nutrients ("press"), which had much reduced calcification (dashed and dotted lines in Fig. 3 in the article).

 

[yuriigeorge]

As Hans Werner put it:

“While phosphate is the principal compound used for nearly all biological processes and compounds, nitrate is not. Nitrate is rather a waste product, the ashes of burnt excess nitrogen compounds.

When after mineralization there is still ammonium left, bacteria use its chemical energy to oxidize it to nitrate, which is a kind of final waste product of nitrogen cycle.”

I see no point in dosing them personally and I dosed them for years before switching to ammonia. In my old 250 it was a night and day difference how the corals reacted and grew under each regiment.

Little dino patches on the sand were almost immediately (within 24 hours) covered in cyano and then went away when dosing ammonia. Those same patches just kept growing dinos with nitrate dosing.

I dose ammonia and rarely even test nitrate. I don’t advocate that anyone else do this especially if new, but if you have a decent grasp on the concept and a little common sense, it works great IME

 

[Randy Holmes-Farley]

Welcome to Reef2Reef, yurrigeorge!

No post came through from you. Did you want to add something?

 

[CHSUB]

There is one quite new article saying that in Acropora intermedia from the Australian GBR nutrient pulses clearly had better effects on coral condition than continuously increased nutrient concentrations, labeled "press" in the article.

Overall the condition of corals was much more balanced and similar to the control corals (red pentagon in Fig. 3) in the pulsed application (black pentagon in Fig. 3) than in the continuous applications of nutrients ("press"), which had much reduced calcification (dashed and dotted lines in Fig. 3 in the article).

Great article…I will summarize: keep nutrients low a possible and feed your corals daily. It is a simple philosophy that I happen to follow.