Originally Posted by Caliban07
I was also under the impression that as well as consuming alkalinity, acidity was produced by the bacteria during the breakdown if ammonia. I need to find this also. That would be doubly important if this was the case. What surprises me though is that people with relatively normal ph struggle. Jen can you find the paper that gives average times for ammonia levels to decrease and nitrites to appear then decrease? I can't find it anywhere but I also think a lot of people are expecting nitrites to drop sooner.
The 7.1 mg
NH4 number that Jen quoted is just the alkalinity consumed buffering the protons created by ammonia oxidation. Any direct carbonate consumption would be in addition to that.
Originally Posted by Calibran07
I've just been looking at an article. It states that 80% of bacteria energy goes on co2
fixation as part of the Calvin cycle. Lower ph has more c02 so it could mean that co2
takes precedence over ammonia in this instance. Maybe why the cycle slows at 6? I'm at work so can't look in to this with more detail.
levels are mostly related to air concentration of CO2
and water temperature; that is to say, CO2
impacts pH much more than pH impacts CO2
would essentially be constant at all pHs for an open system like what we have (where atmospheric CO2
can't be reduced/increased). At lower pHs, you will drive off your carbonate buffers in the form of CO2
, but that's the buffering system working as intended.
Also important to note is that the calvin cycle is separate from ammonia/nitrite oxidation, so I don't think that they would interact in the way you think they would (although I might be misunderstanding you).
If I had to guess why the cycle starts to sputter at low pH, I would probably guess that it had something to do with the bacteria maintaining a proton gradient across their membrane (which is part of the nitrification process) or due to sequestration of ammonia in the ammonium form where it can't be as easily accessed by bacteria's machinery (similar to the detoxification of ammonia at low pH in fish).
Another question I have is does lower ph mean less oxygen?
No. I don't know of anything off the top of my head that relates oxygen concentration to pH. Like CO2
, the main factors in oxygen level is mainly temperature and atmospheric levels, with surface consumption and surface agitation being secondary (but still important) factors.