Ph Effectiveness On Autotrophic Bacteria

[discus_lover]

your article is more clear viewing now...

 

[fatheadminnow]

your article is more clear viewing now...

Thanks! I hope the added section helps explain a little more!

-FHM

 

[Bignose]

I think that there are some things that need to be looked into further.

1) Can you cite where you got the info that the bacteria go dormant at a pH of 6.0? My understanding is that they just don't process as fast, and other bacteria that do process faster at those more acidic pHs can become dominant. This is also only necessarily a problem if you do not plan on keeping your tank that acidic, and there are many species that thrive and require acidic waters.

2) You cite the incorrect species for the two oxidizing bacteria. Recent research published by Hovanec and company have identified other species as the primary oxidizers found in home aquaria. I would strongly suggest you familiarize yourself with that literature. See Havanec et al., Applied and Environmental Microbiology, Jan 1998, Vol 64 and Burrell et al., Applied and Environmental Microbiology, Dec 2001, Vol 67 which discuss Hoavanec's group's research about the nitrite and ammonia oxidizers, respectively.

3) Calling a pH of 6.5 or lower unsafe really isn't supported by facts. Again, there are fish that thrive in that acidic water. There are some fish out there for which a pH ABOVE 6.5 would be unsafe. It is too general of a statement that doesn't fit in enough cases.

4) Be very careful about your use of the word "hard" to describe water. Typically, just saying "hard" refers to the general hardness of the water (usually abbreviated GH). However, what controls the buffering capability of water is the carbonate hardness (usually abbreviated KH). The two are related, but not necessarily the same; and there two different tests to measure each quantity. And, it is possible to have water with high KH and low GH or vice versa, though it isn't typical. But, because it is possible, the two words cannot be used interchangeably. When talking about the buffering capability of water, you have to use KH.

5) Ancillary to points 3 and 4, referring to a "pH crash" as anything below a pH of 6.5 isn't right, either. It depends on the buffering agents in the water. There are buffering agents that keep a pH steady at 4.0 or 6.0.

6) If you are going to recommend water changed to add buffering capability, that sentence needs to include the condition that your tap water have significant KH, which isn't always true. If you tap water has low KH, then water changes aren't going to do anything.

7) if you want the article to look more proper, the scientific names of the species of bacteria should be italicized.

8) Most aquatic plants actually prefer to take up ammonia, not nitrate. In fact, most aquatic plants will expend energy to convert nitrate back to ammonia before they put it to use. See Diana Walstad's excellent book Ecology of the Planted Aquarium for more information.

These are all the points that I see at the moment. If these can be addressed, I think that it will be a very good article.

Can I suggest that you address the points I've raised here and then re-post the article in the scientific section? I didn't even know that this post was written until you asked for it to be pinned in the BA&S section. I just don't read the "New to the Hobby" section very often at all In the scientific section, we have several people who have great knowledge about these more technical aspects of the hobby and they will probably have more questions and comments about the article than just me alone.

 

[fatheadminnow]

Hey BN, thanks for your response!

I think that there are some things that need to be looked into further.

1) Can you cite where you got the info that the bacteria go dormant at a pH of 6.0? My understanding is that they just don't process as fast, and other bacteria that do process faster at those more acidic pHs can become dominant. This is also only necessarily a problem if you do not plan on keeping your tank that acidic, and there are many species that thrive and require acidic waters.

All the facts I used have been cited in the two links that i have provided at the bottom of the article.

2) You cite the incorrect species for the two oxidizing bacteria. Recent research published by Hovanec and company have identified other species as the primary oxidizers found in home aquaria. I would strongly suggest you familiarize yourself with that literature. See Havanec et al., Applied and Environmental Microbiology, Jan 1998, Vol 64 and Burrell et al., Applied and Environmental Microbiology, Dec 2001, Vol 67 which discuss Hoavanec's group's research about the nitrite and ammonia oxidizers, respectively.

Can you please give me links to these articles? The bacteria names I got where from pinned articles in the beginners section. I guess they need to be updated as well.

3) Calling a pH of 6.5 or lower unsafe really isn't supported by facts. Again, there are fish that thrive in that acidic water. There are some fish out there for which a pH ABOVE 6.5 would be unsafe. It is too general of a statement that doesn't fit in enough cases.

I am refering to the Bacteria in this article, more so than fish. Yes, I know fish can adapt and thrive in a wide pH range, however; I wish I can find the article again, there is yet to be evidence the bacteria can do the same. Meaning they cannot adapt to different pH levels, which is why they are so effected by different pH levels.

4) Be very careful about your use of the word "hard" to describe water. Typically, just saying "hard" refers to the general hardness of the water (usually abbreviated GH). However, what controls the buffering capability of water is the carbonate hardness (usually abbreviated KH). The two are related, but not necessarily the same; and there two different tests to measure each quantity. And, it is possible to have water with high KH and low GH or vice versa, though it isn't typical. But, because it is possible, the two words cannot be used interchangeably. When talking about the buffering capability of water, you have to use KH.

5) Ancillary to points 3 and 4, referring to a "pH crash" as anything below a pH of 6.5 isn't right, either. It depends on the buffering agents in the water. There are buffering agents that keep a pH steady at 4.0 or 6.0.

What I mean here, I guess I need to make myself more clear, is that a pH crash in terms on these bacteria. Meaning that they go into a dormant state when the pH drops below a certain level, which would indicate (in this sense) a pH "crash." Not that the pH cannot be stable at a lower levels.

6) If you are going to recommend water changed to add buffering capability, that sentence needs to include the condition that your tap water have significant KH, which isn't always true. If you tap water has low KH, then water changes aren't going to do anything.

All I meant here, is that the tap water pH and the pH in the tank will reach an equilibrium. But you are right, I need to restate that sentence.

7) if you want the article to look more proper, the scientific names of the species of bacteria should be italicized.

Okay, will do.

8) Most aquatic plants actually prefer to take up ammonia, not nitrate. In fact, most aquatic plants will expend energy to convert nitrate back to ammonia before they put it to use. See Diana Walstad's excellent book Ecology of the Planted Aquarium for more information.

Never knew this?

These are all the points that I see at the moment. If these can be addressed, I think that it will be a very good article.

Thanks you, I will see what I can do for now, until you give me those links to those articles, unless it is a book?

Can I suggest that you address the points I've raised here and then re-post the article in the scientific section? I didn't even know that this post was written until you asked for it to be pinned in the BA&S section. I just don't read the "New to the Hobby" section very often at all In the scientific section, we have several people who have great knowledge about these more technical aspects of the hobby and they will probably have more questions and comments about the article than just me alone.

-FHM

 

[Jonathangerous]

I disagree. There is always a thriving microbiota to take advantage of any situation. Nitrification does not suddenly not happen in low pH. Different species or serotypes will have different optimums, but rest assured, assuming your water is at a reasonable (read as: above 6 and below 8-9), your nitrifying community should be just fine. Nitrosomonas are generally quoted as having a pH optimum of around eightish, with activity dropping minimally until below 6.5 or above 9. But most if not all studies are done exclusively on a handful of serotypes. Nature adapts well. See:

http/aem.asm.org/cgi/content/abstract/70/11/6481

 

[Mr Bliss]

There's also been some talk about nitrifying archaea lately. They seem to be responsible for the majority of nitrification in some soil types, but what their significance (not to mention pH optimums etc) is in aquaria, is anybody's guess at this point, although this article about freshwater sediments suggests that they may be abundant in typical aquarium filter/substrate conditions.

 

[fatheadminnow]

I disagree. There is always a thriving microbiota to take advantage of any situation. Nitrification does not suddenly not happen in low pH. Different species or serotypes will have different optimums, but rest assured, assuming your water is at a reasonable (read as: above 6 and below 8-9), your nitrifying community should be just fine. Nitrosomonas are generally quoted as having a pH optimum of around eightish, with activity dropping minimally until below 6.5 or above 9. But most if not all studies are done exclusively on a handful of serotypes. Nature adapts well. See:

[URL="http/aem.asm.org/cgi/content/abstract/70/11/6481"]http/aem.asm.org/cgi/content/abstract/70/11/6481[/URL]

Thanks for your reply, I have made some changes accordingly.

-FHM

 

[aaronnorth]

Also, all nitrification is inhibited if the pH drops to 6.0 or less. This means that the nitrite processing will be extremely slow as well. So, with this is mind, it is extremely important to know the pH of your tank, and keep a close eye on it. If the pH drops close to 6.5, immediate action should be taken. Note: when the pH drops this low, and the Autotrophic bacteria drastically slow down the processing of ammonia or nitrite, this does not mean the the Bacteria have died off at all. In fact, this means that the Bacteria have simply gone into a "dormant" state where they process the ammonia and nitrite at extremely slow rates, and when the pH raises back up above 6.5 or so, the bacteria will then resume production on ammonia and nitrite at their previous capacity.

My pH is near constant pH6 all the time anyway. I dont notice any differences.
ok, i have lots of plants now, (but i have had fish only tanks in the past), however, i also stock my tanks heavily so the amount of ammonia produced wont all be utilised by the plants, so therefore, bacteria must be still functioning at a "normal" rate. It has been shown plants dont use ammonia once the levels get above 0.5ppm. if my bacteria was in the dormant phase all the time, then i wouldnt be able to keep many fish because the NH3 would be too high all the time.

Thanks, Aaron

 

[fatheadminnow]

I made a few changes again, please read and critique.

Thanks!

-FHM

 

[Bignose]

RE 1) the problem is that neither of those sources are truly scientific webpages. Neither cites their sources, neither backs up what they write with addiitonal information, they are just presented as fact. And, as I pointed out in my point #2, at the very least, the facts they state are debatable today. The species identified on those pages have been thrown into question by recent scientific studies wherein other bacterial species have been shown to be dominant.

2) I gave you the citations to those two papers: See Havanec et al., Applied and Environmental Microbiology, Jan 1998, Vol 64 and Burrell et al., Applied and Environmental Microbiology, Dec 2001, Vol 67 you are going to have to go to the library and get them yourself. It is against copyright law for me to download them and give copies away. Your local univeristy library should either have the or be able to get them, or if you go to your local public library and ask the librarian about making an interlibrary loan you should be able to get them.

3) Again, citing a specific number needs to be backed up by fact. Look at this article on the web for example: [URL="http/cobweb.ecn.purdue.edu/~alleman/w3-a...r-behavior.html"]http/cobweb.ecn.purdue.edu/~alleman/w3-a...r-behavior.html[/URL] They cite a specific number (different than yours!) for the low limit of pH, and they back it up with links to scientific papers.

5) I still want more proof of "dormant" state, or at least more details about it. Again, I think that dormant may not be exactly right, but they they jsut aren't as efficient as other species and then those other species become dominant. Again, citing a paper would help a lot.

----------------------------

I went ahead and merged the two threads together here; this thread may read a little funny because merging reorders all the posts together chronologically. I did leave a link in the original subforum this thread was posted in.

 

[andywg]

Can you please give me links to these articles? The bacteria names I got where from pinned articles in the beginners section. I guess they need to be updated as well.

Nitrospira-Like Bacteria Associated with Nitrite Oxidation in Freshwater Aquaria for the 1998 Hovanec et al piece

Community Structure and Activity Dynamics of Nitrifying Bacteria in a Phosphate-Removing Biofilm for the Burrell et al article.

 

[Jonathangerous]

Bacterial dormancy is pretty well documented, but not well understood. If anyone has the time, they should look up GASP/HipA related phenotypes---those are some groundbreaking papers. Of course, there's also sporulation. It's a pretty big thing in current microbiology.

Anyways, a surprisingly large number of bugs have been classified as having dormant states. It wouldn't necessarily be surprising if nitrifiers had such a phenotype as well--there have been a few articles with very sparse evidence in favor of this idea. I'll look them up if I get a chance.

 

[fatheadminnow]

Thanks guys for the responses and for the links!

-FHM

 

[Deleted member 55926]

Really useful thread, thanks.

As a beginner, I would offer this: you might want to recommend that, as a prerequisite, beginners know how the nitrogen cycle works, or at least that they have read the fishless cycle thread. It would help people to understand the context of your information (which I would class as a more advanced addition to the general information about cycling).

Also, small grammatical change: all occurrences of 'effect' should be 'affect'.

 

[AdamM]

i have a pH of nearly 6.0, and ive never had a problem with cycling or ammonia/nitrite processing...