Cycling, CO2 and PH question

[Bradders]

Here's a question for the experts out there.

Assume a constant of CO2 injection 24 hours of the day for this question.

As we are learning on this forum and more broadly, there are different types of nitrification "beneficial bacteria" that form in our filters and aquariums. Some favour growth in a pH of 6 to 8 (Nitrosomonas, Nitrosococcus), while some grow more in conditions (i.e. archaea, thaumarchaeot) that are more acidic—albeit research is saying that the latter grows slower than the higher pH bacteria.

Question: If you have a natural water pH of 6.5, and CO2 injection takes you to a pH of <=5.5 (the 1pH ish drop method), how does the BB 'work'? i.e. even though the natural water is 6.5, does injecting CO2 mean that the beneficial bacteria that form will be archaea, thaumarchaeot rather than Nitrosomonas or Nitrosococcus?

I am trying to work out whether the CO2 alters the water's "natural" chemistry to the point that BB also has to adapt. Or does BB formation/growth take into account the natural water pH position?

I hope that makes some sense. I felt a little lightheaded when writing it to be honest ....... 😱

Regards,
Brad

 

[dw1305]

Hi all,

Some favour growth in a pH of 6 to 8 (Nitrosomonas, Nitrosococcus),

mean that the beneficial bacteria that form will be archaea, thaumarchaeot rather than Nitrosomonas or Nitrosococcus?

I think the answer is that you don't have to worry about it, because the microbes

• <"that were though to occur in our filters">,
• which had been isolated from sewage sludge and
• need high ammonia and carbonate hardness.

don't actually occur in our filters. This is a quote from Tim Hovanec's marine article, it is well worth a read (I have a lot of time for Dr Hovanec).

........ Working in Ed’s lab, I developed molecular probes for Nitrosomonas europaea and closely related ammonia oxidizing bacteria (AOB) and Nitrobacter winogradskyi. I started applying them to samples from various sections of freshwater and marine aquaria (biofi lter material, substrate, and the bulk water). The results were unexpected—Nb. winogradskyi was not detected in any sample while N. europaea-type AOBs were only detected in marine aquaria. Furthermore, if I took a functioning freshwater aquarium and switched it to saltwater by only adding a synthetic salt mix, nitrifi cation halted—as evidenced by the sudden appearance of ammonia and then nitrite (so the tank was going through another cycling period). When I re-probed the tanks, once nitrifi cation became re-established, a positive signal for the presence of N. europaea-type AOBs was detected. Here was the fi rst solid evidence that ammonia oxidation was done by different organisms in freshwater aquaria compared to saltwater aquaria and Nitrobacter winogradskyi was not the nitrite-oxidizing bacteria in either situation .......

Tim Hovanec talks about this in both <"Bacteria Revealed"> & <"Tim Hovanec's "Nitrification in marine aquarium" article"> and we have <"Everyone is right ..."> etc.

...... A useful "filter" reference for this is: Barthelme, R et al (2017) <"Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira" Front. Microbiol., 30>......

It was this research on nitrification that led us to contact <"Dr Hovanec">, and the <"Newton"> and <"Neufeld"> labs.

I'm not a betting man, but if I was? All my money is (on the nose) that "Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira" is the situation <"in our aquariums">.

I am trying to work out whether the CO2 alters the water's "natural" chemistry to the point that BB also has to adapt. Or does BB formation/growth take into account the natural water pH position?

I'd guess the added CO2 and lower pH doesn't make a lot of difference, it doesn't change the alkalinity of the water, you <"just have more D(T)IC">, in the form of extra CO2.

cheers Darrel