Plants absorption of ammonia/nitrate.

[Trouser Cough]

That term "absorb". I never thought about what specifically might be happening in the Ammonia > Nitrite > Nitrate process and then the pic of Duanes culling water lettuce upset my time space continuum.

Up to this point I had always thought of plants consuming various forms of nitrogen and that NH3 / NO2 / NO3 compounds transitioned from pollutant to nutrient to growth. Now I wonder if plants may more accurately sponge like, pulling pollutant from the stream and concentrating it in the plant's structure but not necessarily making it go away. Thoughts?

 

[Backfromthedead]

That term "absorb". I never thought about what specifically might be happening in the Ammonia > Nitrite > Nitrate process and then the pic of Duanes culling water lettuce upset my time space continuum.

Up to this point I had always thought of plants consuming various forms of nitrogen and that NH3 / NO2 / NO3 compounds transitioned from pollutant to nutrient to growth. Now I wonder if plants may more accurately sponge like, pulling pollutant from the stream and concentrating it in the plant's structure but not necessarily making it go away. Thoughts?

The little bit of chemistry class i did retain suggests to me that ammonia is probably the easiest compound to extract nitrogen from...separating hydrogen bonds taking much less energy than separating covalent compounds like no2 or no3.

 

[neutrino]

According to this Salvinia natansdo does better with ammonium (NH4) than ammonia (NH3). If true of other aquatic plants, it would mean tank pH makes a difference.
Nitrogen nutrition of Salvinia natans: Effects of inorganic nitrogen form on growth, morphology, nitrate reductase activity and uptake kinetics of ammonium and nitrate

I found this, quite an interesting read. It's complicated as expected, given the subject matter. It helps me understand a little better of how the relationship between plants and ammonia/nitrate works.

Plants and Biological Filtration - The Free Freshwater and Saltwater Aquarium Encyclopedia Anyone Can Edit - The Aquarium Wiki

www.theaquariumwiki.com

.

Found this excerpt interesting:

The energy required for nitrate reduction is equivalent to 23.4% of the energy obtained from glucose combustion [1]. Thus, if nitrifying bacteria in biological filters convert all available ammonium to nitrates, plants will be forced—at an energy cost—to convert all the nitrates back to ammonium. This may explain why several aquatic plants (e.g., water hyacinth, Salivinia molesta, hornwort, and Elodea nuttallii) seem to grow better with ammonium or an ammonium/nitrate mixture than when they are forced to grow with pure nitrates [2]. The nitrogen cycle is often presented incorrectly to hobbyists as nitrifying bacteria converting ammonium to nitrates and then plants taking up nitrates. Actually, it consists of both plants and bacteria competing for ammonium. Only if plants are forced to, will they take up nitrates. Thus, nitrates may accumulate even in planted ponds and aquariums.

 

[Trouser Cough]

Some amalgam of the information in this thread could eventually offset the need to cycle a tank in the traditional way.

If it is true that ammonia is a preferred nutrient it should also be true that dumping a carnivore in an uncycled aquarium should not be an issue as long as you had a layer of duckweed or similar on top and if the ammonia could be consumed at an appropriate rate the tank would naturally cycle. That cycle would be complete once the duckweed stopped growing at an exponential rate (that, or I'm wrong).

I toyed w/ this earlier this year. I skipped a WC on a 110g grow out (peacock bass) and waited until there were visible proteins at the surface then tossed one cup of duckweed into the tank. My experience was that the volume of duckweed more than doubled within a week and the proteins at the surface disappeared within 3-4 days but I didn't monitor NH3 > N02 > N03 as if the test were formal and I didn't write water parameters down at all

Might try that again this year and document water parameters. To do it right would probably need to start with a sterile tank and filter but that seems like a lot more risk than I would normally take.

I'll ponder this for a good while first but the trial that comes to mind would be a fresh and clean grow out (could use same 110g), an FX6 full of pool balls only and a bag of clean bio-ceramic rings somewhere in the tank, preferably in mild filter return current.

Does this seem a little too risky?