Nitrate mystery

[Dan_P]

It seems logical to me, and while I cannot know the magnitude of the effect, I’m relatively confident it is real. Taken to an absurd extreme, the alternative view is that a vanishingly small amount of surface area will have just as much nitrifying capacity as a large amount of surface area.

There are many different organisms that will take up ammonia. They occupy different spaces in the aquarium. If one makes a large amount of real estate that is only available to microorganisms, microorganisms will be able to take up more and other organisms less, just like having 500 corals might take up more than a single coral of the same size.

The absurd extreme is absurd only when you don’t factor in that one needs to feed nitrifying bacteria more to have a larger nitrifying capacity, not increase surface area. You only increase the potential for more nitrifying bacteria growth by increasing surface area, not the capacity. For example, in a new aquarium, one doses more ammonia not surface area to increase nitrification capacity.

Of course other microorganisms take up ammonia, but again, unless you feed them more, there is not going to be a large increase in their biomass just because there is more surface area. And while 500 coral will consume more nutrients than one coral can, that one coral will never become 500 corals (or equivalent biomass) unless more and more nutrients are made available no matter how much the aquarium is enlarged.

I think the experiment to demonstrate this is one with an established nitrifying bacteria population. Double the surface area but don’t change the daily dose of ammonia. Does that aquarium’s consumption of ammonia increase? Or do the same thing with heterotrophic bacteria. Does adding more surface area with a constant feed rate increase the rate of oxygen consumption?

 

[Randy Holmes-Farley Verified Community Expert]

The absurd extreme is absurd only when you don’t factor in that one needs to feed nitrifying bacteria more to have a larger nitrifying capacity, not increase surface area. You only increase the potential for more nitrifying bacteria growth by increasing surface area, not the capacity. For example, in a new aquarium, one doses more ammonia not surface area to increase nitrification capacity.

Of course other microorganisms take up ammonia, but again, unless you feed them more, there is not going to be a large increase in their biomass just because there is more surface area. And while 500 coral will consume more nutrients than one coral can, that one coral will never become 500 corals (or equivalent biomass) unless more and more nutrients are made available no matter how much the aquarium is enlarged.

I think the experiment to demonstrate this is one with an established nitrifying bacteria population. Double the surface area but don’t change the daily dose of ammonia. Does that aquarium’s consumption of ammonia increase? Or do the same thing with heterotrophic bacteria. Does adding more surface area with a constant feed rate increase the rate of oxygen consumption?

I agree that an experiment would be very interesting, if difficult to design and implement.

I guess I’m not really understanding why this is not intuitively correct in principle. If any corals are getting ammonia, then there is ammonia available for more bacteria to take up available space. It’s not all being used by the existing bacteria, and if you then add more space for bacteria, some will take up the challenge and grow on the new space, using ammonia.

 

[Fish Fan]

Pardon me, and at risk of poking my nose through the ice hole like a seal in Eskimo country....

Wouldn't a big part of this conversation depend on the coral load of the tank?

The microbes will grow to whatever their limiting factor is. If you have a 50 gallon tank with one frag in the middle and a bunch of fish, a great percentage of the ammonia would go to the microbes. But in a more mature tank with much greater coral bioload, would there be a time when the corals could/would outcompete the microbes?

Is this why at Dan suggests that there's not a lot of nitrifier DNA in reef tank samples (that I assume are mature, coral tanks)?

Would this mean that in the early stages of a tank, the microbes are the important nitrifiers, and then as the tank matures with corals they become the primary consumer of ammonia?

I'd like to please ask again if there's a consensus on who are the microbial ammonia oxidizers in aquaria, bacteria and/or Archea? <This question is of particular interest to me.

Pardon me again if I have this wrong or am just late to the party

Thank you, smart people!!

 

[JonasRoman]

My tank is a mixed reef (leathers are the only thing not in here) and reads .08 phosphate and 0 nitrates and has for 6 months. All my coral are bright and happy and growing. I have zero pest algae or algae of any kind. I know not to chase numbers I just don’t want to bottom out and get issues.
I have all real pukani stone. Live sand bed about an inch and half thick. Tons of bio media in my sump. A fleece roller is my only mechanical filtration. I do 10% water changes every week. I use aqua forest pro hybrid salt. I dose microbacter 7 when I do my water changes. I dose pods and phyto here and there. And I dose Aquaforest 3-1 daily.
I feed twice a day. A frozen slurry twice a week. The rest of the time a mix of PE mysis, vitalis pellets, TDO, and hikari seaweed extreme. I also feed benereef twice a week.
Why do I have 0 nitrates?!
And maybe a stupider question to those much smarter than me but is it possible I do have enough nitrates and my system is just processing them so efficiently that it reads 0 but it’s there?
I figured by now I’d see some form of pest algae or problem but everything is for lack of a better term perfect.
Also how can I increase nitrate if I need to without increasing phosphate?

Its for me not mysterious at all. You have apparently enough with area for denitrification bacteria, and I am not surprised as you have both a decent sand bed and lot of biomedia in sump. So all nitrate that sooner or later are produced by the nitrification, is converted to N2 gas thanks to this. This is a no issue, be happy your denitrification is in balance with nitrate formation.

I would just be happy for that scenario and do nothing as long as everything looks good. As you seems have biological margins I would consider buying more fish.

 

[Dan_P]

I agree that an experiment would be very interesting, if difficult to design and implement.

I guess I’m not really understanding why this is not intuitively correct in principle. If any corals are getting ammonia, then there is ammonia available for more bacteria to take up available space. It’s not all being used by the existing bacteria, and if you then add more space for bacteria, some will take up the challenge and grow on the new space, using ammonia.

For a fixed amount of ammonia, the bacteria are likely in a stationary growth phase where growth rate equals death rate (predation too).. Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

If true that more surface area does not increase the nitrifyer population, I wonder if the rate of ammonia capture by a biofilm increases. If more surface area spreads out the nitrifyer population, one could argue that an ammonia molecule would encounter a biofilm more often than a coral surface. The experiment I had in mind would measure ammonia draw down rate and might see this effect, though not detect population size differences. So what, right?

After your next reply, I will run experiment design details for your feedback, unless you totally deflate my balloon :-)

 

[Randy Holmes-Farley Verified Community Expert]

For a fixed amount of ammonia, the bacteria are likely in a stationary growth phase where growth rate equals death rate (predation too).. Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

If true that more surface area does not increase the nitrifyer population, I wonder if the rate of ammonia capture by a biofilm increases. If more surface area spreads out the nitrifyer population, one could argue that an ammonia molecule would encounter a biofilm more often than a coral surface. The experiment I had in mind would measure ammonia draw down rate and might see this effect, though not detect population size differences. So what, right?

After your next reply, I will run experiment design details for your feedback, unless you totally deflate my balloon :-)

I guess I just don't agree with this assertion:

Adding surface area would not result in a higher growth rate and more bacteria stealing ammonia because food not surface area is limiting growth.

I'll say up front, we have no idea which organisms are actually taking up ammonia in an ordinary reef tank. Corals, bacteria, algae, and many species of each. Each will have somewhat different capabilities of taking up ammonia. That is, if we artificially lower ammonia more and more, some will drop out of the competition before others. So ammonia is not a hard and fast limitation at some fixed concentration that the tank stabilizes at, below which nothing changes. It's the mix of organisms taking it up that changes.

If any bacteria species are able to take ammonia at levels equal to or lower than corals, and if corals are actually getting any, then if we add more surface area, I think it is a perfectly viable hypothesis that more of the best ammonia scavengers will take hold and steal ammonia from corals. They could not do so to the same extent previously because space was limiting their ability to dominate the competition. But with space not a limitation, we can have more of the best scavengears that are able to beat out corals.

 

[Randy Holmes-Farley Verified Community Expert]

Pardon me, and at risk of poking my nose through the ice hole like a seal in Eskimo country....

Wouldn't a big part of this conversation depend on the coral load of the tank?

The microbes will grow to whatever their limiting factor is. If you have a 50 gallon tank with one frag in the middle and a bunch of fish, a great percentage of the ammonia would go to the microbes. But in a more mature tank with much greater coral bioload, would there be a time when the corals could/would outcompete the microbes?

Is this why at Dan suggests that there's not a lot of nitrifier DNA in reef tank samples (that I assume are mature, coral tanks)?

Would this mean that in the early stages of a tank, the microbes are the important nitrifiers, and then as the tank matures with corals they become the primary consumer of ammonia?

I'd like to please ask again if there's a consensus on who are the microbial ammonia oxidizers in aquaria, bacteria and/or Archea? <This question is of particular interest to me.

Pardon me again if I have this wrong or am just late to the party

Thank you, smart people!!

So I'm not addressing the amount of nitrifiers DNA data since I think it has plenty of caveats, including the one you pointed out about which organisms they actually are, and really a huge disconnect between measuring amounts of DNA and thereby quantifying the nitrifying capacity of microbes with that DNA.

It may well be true that corals can outcompete microbes. That is one of the big missing bits of data:

With one coral and one microbe in the same water, if we lower ammonia more and more, which falters first?


My hypothesis assumes there is an overlap between the corals and microbes taking up ammonia. If bacteria always get it all, or if corals always get it all, my hypothesis fails.