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!!