Water Changes With Normal Parameters

[andywg]

It should be noted that in closed systems, especially in an aquacultural setting, the nitrogen cycle is very much microbiologically different from what we're used to in the home hobbyist trade, simply due to the vast fluctuating quantities of nitrogenous wastes released.

Given that this thread has relied heavily on peer reviewed articles, do you have any observational evidence that a larger closed system is massively different to a smaller closed system? Are you claiming that different strains of bacteria develop?

And is there really a vast fluctuation in quantities of nitrogenous waste? I would have thought that a fish farm would want to be able to have a constant supply to sell, and so would have a number of fish at differing levels of growth meaning that the overall waste production is fairly even.

To quote 4chan: Sauce!

 

[Jonathangerous]

"Are you claiming that different strains of bacteria develop?"

Yes, I am. Some of the biggest names in aquatic nitrogen cycling i.e., Mobarry, Schramm, and a number of Taiwanese articles which recently hit the shelves describe this exact subject in great detail.

The oldy but goody Structure and Function of a Nitrifying Biofilm as Determined by In Situ Hybridization and the Use of Microelectrodes is a good place to start.

"I would have thought that a fish farm would want to be able to have a constant supply to sell, and so would have a number of fish at differing levels of growth meaning that the overall waste production is fairly even."

Key phrase here is that everything in science is relative. In large aquacultural facilities, especially those in which sections of natural watersheds are manipulated for rearing fish, it is impossible to maintain the same level of equilibrium that is present in the home aquaria. Hence, as anybody in the field can tell you, even minute modulations in microenvironmental parameters result in largely different microbiota profiles (see above referenced articles for more details). There tends to be a larger biodiversity, therefore, in said conditions.

It should also be mentioned, that in most aquastock, especially in adro. fishes, such as salmonoids, the fish are moved up and downstream, depending on their developmental age. Needless to say, in each of these different holding pens, you have radically different bugs.

 

[andywg]

"Are you claiming that different strains of bacteria develop?"

Yes, I am. Some of the biggest names in aquatic nitrogen cycling i.e., Mobarry, Schramm, and a number of Taiwanese articles which recently hit the shelves describe this exact subject in great detail.

The oldy but goody Structure and Function of a Nitrifying Biofilm as Determined by In Situ Hybridization and the Use of Microelectrodes is a good place to start.

Although this last article also talks of looking for bactgeria from the genus Nitrobacter which, as has been shown by the work of Hovanec et al, is not now believed to be the main nitrite oxidising strain (this task seemingly being performed by Nitrospira it is of some use when looking at a biofilm, but I don't really see anything in there suggesting that a larger closed system (fish farm) will have a massively different set of AOB and NOB bacteria than a smaller closed system (aquarium).

I would be interested if you could post the names of any subsequent articles, especially any conducting a similar experiment but looking at Nitrospira and Nitrosomonas.

Key phrase here is that everything in science is relative. In large aquacultural facilities, especially those in which sections of natural watersheds are manipulated for rearing fish, it is impossible to maintain the same level of equilibrium that is present in the home aquaria. Hence, as anybody in the field can tell you, even minute modulations in microenvironmental parameters result in largely different microbiota profiles (see above referenced articles for more details). There tends to be a larger biodiversity, therefore, in said conditions.

Care to quote some of the articles? Given that a smaller body of water will show a greater change in parameters (such as butrients entereing upon feeding) one could put forward an argument that there is less equilibrium in a tank than a large system which has a larger volume of water to dilute. I do fear, however, that much of this will be hyopthetical discussions as I doubt anyone has done any real studying of the biofilm in home aquaria.

It should also be mentioned, that in most aquastock, especially in adro. fishes, such as salmonoids, the fish are moved up and downstream, depending on their developmental age. Needless to say, in each of these different holding pens, you have radically different bugs.

Indeed, though I think you will agree that this doesn't relate directly to Tilapia aquaculture which has been the focus of the debate thus far.

 

[Jonathangerous]

"Although this last article also talks of looking for bactgeria from the genus Nitrobacter which, as has been shown by the work of Hovanec et al, is not now believed to be the main nitrite oxidising strain (this task seemingly being performed by Nitrospira it is of some use when looking at a biofilm, but I don't really see anything in there suggesting that a larger closed system (fish farm) will have a massively different set of AOB and NOB bacteria than a smaller closed system (aquarium)."


You just answered your own question. Nitrospira were not found in the eel farm in which the study was done. Instead, Nitrobacter were the main NOB constituent organisms. Nitrospira do better in lower ammonia environments, whereas nitrobacteriacae are more frequently found in higher ammonia output environments. Differeing ammonia concentrations also affects the specific strains of nitrosomonas spp. involved in aob.

 

[Jonathangerous]

"Care to quote some of the articles? Given that a smaller body of water will show a greater change in parameters (such as butrients entereing upon feeding) one could put forward an argument that there is less equilibrium in a tank than a large system which has a larger volume of water to dilute. I do fear, however, that much of this will be hyopthetical discussions as I doubt anyone has done any real studying of the biofilm in home aquaria."

On a very theoretical level, given that the vast majority of aquaculture facilities are located outside, the ambient temperature is already a variable enough factor--and, if you're familiar with AOB/NOB biology, temperature differences greatly increase and decrease efficiencies of nitrogenous waste metabolism. Also referenced in the above article. Ammonia and nitrite are also seemingly always present to some degree in aquaculturing facilities, which lends more credence to the two being incomparable.


"Indeed, though I think you will agree that this doesn't relate directly to Tilapia aquaculture which has been the focus of the debate thus far."

Making a general case for environmental fluctuations resulting in a more diverse microfauna, I would say that it does.