Ammonia production rates

[Tenko]

Hi

Odd question, not sure it belongs in the tropical chat section, but here goes.

For a uni project I'm doing I'm trying to roughly simulate the nitrogen cycle in an aquarium. I've got an equation which calculates the amount of free ammonia based upon the amount of ammonia present, but I need to work out how much ammonia is produced in the first place.

I understand that the production rate per fish will vary dependent upon the amount of food, their size, breed, etc, but I've been trying to find an approximate figure which I can adjust based upon these variables.

I've drawn a blank in all of the books I've managed to track down, can't find it on the net, not even down the back of the sofa.

Anyone got any ideas of a decent source of information? I'll need to reference it too. Any suggestions will be appreciated.

Cheers

 

[jflowers]

I have a magazine with an artical on filtration that states the approximate amounts of protien in foods needed to produce the least amount of ammonia, but no actual scientific figures. It only says that a predatory fish will utilise more protien than a herbivore, but does give some percentages for each type of fish. If this is any good to you I will PM you the magazine name.

Jon

 

[steelhealr]

Hi Tenko....tough one. I majored in Biochem and studied a lot on surgical nutrition and metabolism. The variables involved with the production of ammonia by fish is going to be extremely difficult to calculate. Ammonia is a breakdown product of protein and as such, varies on an individual fishes metabolism. Not only will it depend on what the fish eats, but, it's activity and even WATER TEMPERATURE. Fish metabolism, like any living creatures, will tend to increase with high temperature and decrease with low. You would probably be better off picking a model with a fixed constant supply of ammonia, ie, a fictional fish that constantly secretes x amount of ammonia...perhaps then make a model based on increasing the number of fish. It's not the perfect setup but would be a start. What do you think? SH

 

[Bignose]

Have you used something like the Science Citation Index? Or Lexus-Nexus? your university should have access to one of these databases that allow you to search through journal articles. Ask your reference desk at the library.

For example, in the science citation index, also known as web of science at http/www.isiknowledge.com, a search for "ammonia production and fish" found:

Title: Dietary manipulations affecting growth and nitrogenous waste production of red drum, Sciaenops ocellatus I. Effects of dietary protein and energy levels
Author(s): McGoogan BB, Gatlin DM
Source: AQUACULTURE 178 (3-4): 333-348 AUG 1 1999

Title: Apparent ammonia-nitrogen production rates of white sturgeon (Acipenser transmontanus) in commercial aquaculture systems
Author(s): Thomas SL, Piedrahita RH
Source: AQUACULTURAL ENGINEERING 17 (1): 45-55 FEB 1998

Title: The influence of feed protein intake on tilapia ammonia production
Author(s): Brunty JL, Bucklin RA, Davis J, Baird CD, Nordstedt RA
Source: AQUACULTURAL ENGINEERING 16 (3): 161-166 MAY 1997

Title: A simulation model of ammonia dynamics in commercial catfish ponds in the southeastern United States
Author(s): Hargreaves JA
Source: AQUACULTURAL ENGINEERING 16 (1-2): 27-43 MAR 1997

All in all 37 articles in the web of science database have "ammonia production" and "fish" in the title or abstract. As with most search engines you will have to search with other terms to find all the papers, but this should give you a good start. The best thing about the science citation index is that you can see what newer research cites a given article, so you can see what other researchers have done with the work.

 

[Tenko]

Thanks.

I've used the Science Citation Index to get information on the overall nitrification process. I asked for 4 publications from my uni, they only gave me 2 as I'm just an undergrad and they reserve their service primarily for postgrads. Of course, I thanked them for their incredibly gracious act of supplying any at all. After all, it's not as if I'm paying for the privilage or anything.

I'll have a search right now and see what they have, although I don't think I can get any without paying which my uni library doesn't hold (they don't have many). Although last time I was able to track down a couple I wanted free on the net so I'll try that.

You are right that it's an almost impossible task to accurately simulate it. I've cut the scope of the simulation down a lot due to time constraints so won't be doing it as accurately as I had hoped.

Instead I plan to have a choice of approx 5 fish species, each species producing an approximate amount of ammonia. I hope to estimate this from an overall generic figure if I cannot find more accurate information, smaller fish producing less etc. This amount will be affected by the regularity of feeding and tank temperature.

The total produced will be dependent upon the number of fish in the tank, I hope to calculate the surface area of the specified filters and other objects in the tank and use this to calculate the nitrification process. The quantity of plants and water changes will then affect the level of nitrates etc.

Although I won't be doing a simulation from tank inception including cycling etc, I will be calculating nh3, nh4, no2 and no3. Firstly so I have a semi-accurate no3 amount and secondly to enable me to expand the simulation to include cycling if I feel that way inclined. Besides, I might get some extra marks if the program is expandable.

I didn't realise it would be so difficult to track down decent information on this sort of thing. But then, I don't suppose many academic courses require much more than the basics of nitrification. My girlfriend is on a biomedical degree and none of the books she has go into much detail at all.

 

[steelhealr]

Surface area of gravel? Can you measure or extrapolate rate of conversion/nitrification based on numbers of bacteria? Good luck with your project. SH

 

[sammydee]

You would need the surfave area of every item in the tank and the amount of water passing over it. I personally think there are too many variables for it to work, and at best you will end up with quite a rough answer, but its worth a try. Good luck!

 

[Bignose]

You will want to look into water treatment literature also. There is quite a lot of information about nitrification and denitrification in waste water treatment plants, and civil engineers have been concerned with topics like this for quite some time. The invention of the bio-wheel was inspired by similar devices in waste-water treatment.

 

[Tenko]

There are far too many variables to predict it accurately, the best I am expecting is an approximation of the process. The exercise is more to show that I can model a complex process and design and build a software solution.