Do we need Nitrate in a reef tank?

[biom]

The thread title says it but I want to discuss if there is any need of nitrogen in form of nitrates in a reef tank. I am not aware of any desirable organisms in our reefs which are dependent of nitrate availability in the water with the exception of denitrification bacteria.
Just to stress out again I am not talking about the Nitrogen per se but Nitrogen in the form of Nitrates.

 

[Timfish]

No. Corals prefer Dissolved Organic Nitragen (amino acids and urea) and the Dissolved Inorganic Nitrogen form ammonia over nitrate. Corals may also have diazotrophs that can convert N2 to nitrates. Shantz and Burkpile reviewed a bunch of research and found nitrates can deperess calcification. Here's fig 3 from their paper:

 

[biom]

Thanks for sharing @Timfish good read. Makes sense - Corals are more adapted to Ammonium - since the fish and crustaceans excrete nitrogen in form of Ammonia (not like us mammals in form of urea and uric acid...) And also having in mind nitrogen in NO3 is in maximum oxidation state so its availability to corals comes with a high energy price.
There are so many reefers recently dosing nitrate. But would it be wise to recommend dosing ammonium instead of nitrate?

 

[Red_Beard]

I was wondering this also. I was reading a few studies on nitrogen and phosphorus uptake rates in coralline and it mentioned the same thing. The gist was that ammonia was much more suitable for uptake and would be utilized before other nitrogen sources. I have also seen that mentioned in a few coral studies too.
I wonder if the aversion to ammonia dosing comes from the stigma surrounding ammonia levels in your tank through the inital nitrification cycle. "0 ammonia or no fish!"
I would think that a sufficient fish population being adequately fed would generate enough free ammonia to support the metabolic processes in the surrounding coral. But maybe it isnt sufficient? So the get as much as they can and then and only then turn to No3? Dunno. That is an interesting line of thought though.

 

[Dennis Cartier]

I have used ammonium in the past for dosing. It works fine. Best to spread it out and dose it slow, not all at once.


Some threads on using it, and making dilutions.

Is nitrate dosing effective

Is there a difference between nitrate from fish waste and nitrates that were directly dosed when it comes to coral metabolism? Well you raise a really good question and I've often wondered the same thing. In my current tank I've struggled to keep my nitrates up at a level I want, and I've...

www.reef2reef.com

Combined Ammonium Chloride / Diammonium Phosphate Dosing Solution

I am trying to calculate how much ammonium chloride, diammonium phosphate and sodium carbonate is required to create 1L of solution that will add 0.1 ppm ammonium and 0.01 phosphate when 1 ml is dosed into 100G and not raise or lower alkalinity. I think it is: 121.28 g ammonium chloride 120.06...

www.reef2reef.com

Note: For the combined solution (N : P), I found that a 10:1 N : P was not balanced enough. I would suggest 15 - 20:1 as a starting point, or just keep them separate and dose them separately.

 

[Dennis Cartier]

I think Hans said it best here: "Nitrate is rather a waste product, the ashes of burnt excess nitrogen compounds."

NP Plus - Phosphate / Nitrate ratio

According to previous threads on NP Plus, I am suppose to test phosphate only because nitrate is expected to remain 0 while using NP Plus. I did not know that at first so I kept dumping NP Plus and testing my nitrate. I finally got a Hanna Phosphate test kit and it is reading 0.39 for...

www.reef2reef.com

 

[Randy Holmes-Farley]

I think the question is too vague.

Having detectable nitrate assures there is sufficient N for organisms we keep, and many organisms can use it if they need to.

It does not mean that one must have nitrate if the other sources are sufficient, but since we do not measure these other sources, having it is an insurance policy, even if it it is not the primary form of N consumed.

 

[biom]

I think the question is too vague.

Having detectable nitrate assures there is sufficient N for organisms we keep, and many organisms can use it if they need to.

It does not mean that one must have nitrate if the other sources are sufficient, but since we do not measure these other sources, having it is an insurance policy, even if it it is not the primary form of N consumed.

I think the question is quite clear. And we can easily measure ammonia for sure.

 

[Miami Reef]

And we can easily measure ammonia for sure.

No we can’t. Ammonia in established tanks are too low for our hobby grade kits.

 

[rtparty]

Are nitrates NEEDED? My research leans towards no. Are they an easy way to measure if we are adding enough ammonium? Absolutely.

IMO, this is why it doesn’t matter if nitrates are 2 or 40. I’ve yet to see any negatives from high nitrates. What the high nitrate number is telling us is we are adding more ammonium than our corals and algae can uptake before it’s converted into nitrates. So keeping a lower nitrate number is preferable as that means we are adding just more than enough for our inhabitants.

The thread Dennis posted above from Hans is probably the best I’ve found to date talking about it all

 

[Miami Reef]

I personally see nitrate as an insurance policy. I know corals prefer ammonia, but there is a lot of competition for ammonia: bacteria, algae, etc

I only feed 1 time a day, so I want to make sure corals always have a source of N. They can use nitrate, but it takes a little energy from them to convert it to ammonia.

 

[Labridaedicted]

Depends on what kind of life you're talking about. Corals almost assuredly require some as they rely on plants within their tissue and a form of nitrogen is requires for plants to thrive.

That being said, "Nitrates" aren't necessary, but a form of nitrogen is.

 

[GatorGreg]

I think the question is quite clear. And we can easily measure ammonia for sure.

Lol you do realize who you’re talking to right? If you don’t agree with him it’s probably because you don’t understand what he’s talking about. I think you’re in over your head here bud.

 

[Randy Holmes-Farley]

I think the question is quite clear. And we can easily measure ammonia for sure.

The written question is clear and the obvious answer is no, nitrate is not needed at a level detectable by typical hobby kits. N can certainly be supplied in other ways, but that does not mean that it "IS" sufficiently available in other ways.

A more in depth consideration of the question and the implications of the answer is what makes it vague. To say it is "not needed" means you have other ways of ensuring enough N is present. Few reefers do that, so for all of them, nitrate is needed, IMO, while for some tanks, it may not be actually needed to be present.

You can possibly measure ammonia, but you do not know what level is needed or what the flux through that concentration is taking place.

Suppose, for example, you measure 0.001 ppm ammonia. Is that sufficient to meet organism needs? 0.01 ppm? 0.001 ppm?

 

[bushdoc]

I think we do, even if nitrates are not utilize directly by corals, levels above zero indicates that you are providing enough nutrients to your reef aquarium.
Similarly if your urine urea is low it may indicate diet low in protein/malnutrition ( among other things).

 

[Dan_P]

I think the question is too vague.

Having detectable nitrate assures there is sufficient N for organisms we keep, and many organisms can use it if they need to.

It does not mean that one must have nitrate if the other sources are sufficient, but since we do not measure these other sources, having it is an insurance policy, even if it it is not the primary form of N consumed.

If you aren’t keeping coral, would the answer be “detectable nitrate is unnecessary”?

 

[Randy Holmes-Farley]

If you aren’t keeping coral, would the answer be “detectable nitrate is unnecessary”?

I think it applies to other photosynthetic organisms as well, but not to much else. I can certainly imagine, for example, that if N is too low, certain macroalgae may suffer, and having detectable nitrate assures there is enough.

 

[Randy Holmes-Farley]

Discussing this question from a different approach, one question is whether there is any organism in a reef tank with an absolute requirement for nitrate, which cannot be satisfied by another molecule.

I'm not aware of any such organism larger than microbes, and I think it's perhaps an open question on many microbes whether even those that perform, say, denitrification, actually need nitrate to survive or if they can get energy in other ways in a reef aquarium.

 

[Timfish]

Thanks for sharing @Timfish good read. Makes sense - Corals are more adapted to Ammonium - since the fish and crustaceans excrete nitrogen in form of Ammonia (not like us mammals in form of urea and uric acid...) And also having in mind nitrogen in NO3 is in maximum oxidation state so its availability to corals comes with a high energy price.
There are so many reefers recently dosing nitrate. But would it be wise to recommend dosing ammonium instead of nitrate?

Rather than dose ammonia I'd feed more or add more fish and feed more. Fish poop also contributes to the carbonate cycle.

Fish as major carbonate mud producers and missing components of the tropical carbonate factory

https://www.pnas.org/doi/10.1073/pnas.1015895108

Just FYI, while a fair amount of fish nitrogen waste is excreted as ammonia/ammonium from their gills they do produce urea also. Here's some more links if you're interested:

Ammonium Uptake by Symbiotic and Aposymbiotic Reef Corals

Ammonium Uptake by Symbiotic and Aposymbiotic Reef Corals: Ingenta Connect

www.ingentaconnect.com

Amino acids a source of nitrogen for corals

Uptake of dissolved free amino acids by the scleractinian coral Stylophora pistillata

SUMMARY. This study was designed to assess the importance of dissolved free amino acids (DFAA) as a nitrogen source for the scleractinian coral Stylophora pistillata. For this purpose, experiments were performed using 15N-enriched DFAAs, and %15N enrichment was measured both in animal tissue and...

journals.biologists.com

Urea a source of nitrogen for corals

Urea uptake by the scleractinian coral Stylophora pistillata

Urea can be one of the major sources of nitrogen for phytoplankton, but little is known about its importance for corals. Experiments were therefore de…

www.sciencedirect.com

Diazotrpophs a source of nitrogen for corals

Diazotrophs: a non-negligible source of nitrogen for the tropical coral Stylophora pistillata - PubMed

Corals are mixotrophs: they are able to fix inorganic carbon through the activity of their symbiotic dinoflagellates and to gain nitrogen from predation on plankton and uptake of dissolved organic and inorganic nutrients. They also live in close association with diverse diazotrophic communities...

pubmed.ncbi.nlm.nih.gov

Effects of anemonefish on giant sea anemones: Ammonium uptake, zooxanthella content and tissue regeneration

https://www.tandfonline.com/doi/abs/10.1080/10236240500057929#.UpS4pyeJ7Mo

Nitrogen cycling in hte coral holobiont


Nutrients and Sponges


Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution
(here's an argument for maintaining heavy fish loads if you're carbon dosing)

Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution

Labile dissolved organic carbon (DOC) is a major pollutant in coastal marine environments affected by anthropogenic impacts, and may significantly con…

www.sciencedirect.com

 

[Dan_P]

I think it applies to other photosynthetic organisms as well, but not to much else. I can certainly imagine, for example, that if N is too low, certain macroalgae may suffer, and having detectable nitrate assures there is enough.

OK, this helps set the boundaries to the question.