Do the bacteria really die in the bio filter?

[fiftycal]

Theres alot of belief that bacteria die when you stop the filters running, or you let them dry out. Is this true?

I am not talking about them being exposed to chlorine or any antibacterial agents, I am simply talking about the water supply being cut off, such as a filter being turned off for prolonged periods of time.

Do the bacteria actually die, or do they simply stop replicating? Now keep in mind, bacteria do not "die" like we do. Bacterial "death" is pretty much when a single cell gets so old that it stops replicating. The other bacterial "death" is from the use of chemicals or antibiotics or phages or methods of steralization, such as UV light and gamma rays.


I believe that these beliefs may simply be myths:

1. The temperature does not fluctuate to any extremes when the filters are stopped. Even if its a bloody cold place and it goes to -10C or whatever, the bacteria still should be able to survive. Yes, the temperatures may be non optimal, but bacteria still can survive in sub zero temperatures.

2. The lack of nutrients will not kill the bacteria. When bacteria do not have any nutrients, they go into a "stationary phase", where a whole heap of cellular things change so that they can still survive. However, what do the denitrifying bacteria use as a substrate once nitirites are absent? There are many different types of denitrifying bacteria, and I am not sure which is the most prevalent type in aquarium filters. It is possible that these bacteria will change substrate to other nutrients in the water, and the product may potentially be unwanted. However, once nitrites are made available, they should revert back to using nitrites as a substrate.

3. The lack of oxygen will not kill the bacteria either. Similarly to (2), if they are aerobic only, which is unlikely, they will go into a "stationary phase". It is highly likely that the vast majority of bacteria present can work both anaerobically and aerobically. When bacteria use aerobic pathways, they are MUCH more efficient.

4. There is no changing concentration of salts. Even in the "stationary phase", they would be able to resist high salt concentrations anyway. Some bacteria can even resist high concentrations of bleach!


I got that from doing micro, and part from another fish forum lol. Is there any real proof that the bacteria die, or is it simply a myth?

[fishgeek]

bacteria in a filter are subject to all the same osmotic and chemical stress's that a fish would be

yes i agree they are likely to be hardier(or maybe just so much more abundant that the occasional deaths go by unoticed)

they do require oxygen and can die as son as oxygen depletion occurs in the water surrounding them, ie the filter stops running

they do require food, and hence once the water stops running and bring them food they can starve, yes they can live for a while, i still rememer the australian guy(brisbane actualy) that got lost in the himalaya's and lived for 40 days with just a mars bar and melted snow... i know myeslf and lots of others who wouldnt last

they do excrete products waste to them that they do not want, these can build up and in non circulating water and cause problems

dessication is certainly detrimental to bacteria

every living thing has a set of requirements and a range in which it can survive
yes i agree bacterial range's maybe wider and they certainly can still be damaged by not providing those ranges/requirements

i think the exact species of biobacter are not fully understood and i am not a microbiologist to tell us whether those bacteria have a sporulating or dormant phase
nor for how long that dormant state can be maintained in suboptimal conditions

i guess this is a discussion without a fully documented answer
and my answer would be that all things that are harmful and lead to dormancy, if done at higher level or for long enough are likely to cause death

andrew

[ILLUSN]

filter bacteria can die, i left a canister unplugged for a couple of weeks, opened it up and it stunk of dead fish and mud, all the aerobic bacteria were dead.

A healthy functional filter will never stink like that

see this post.

http://www.discusforums.com/forum/viewtopic.php?t=10949

[Merrilyn]

That's a great question.

Can't give you scientific reasons, like our vet fishgeek, but I can tell you from experience, that a filter that's been turned off for 12 hours WILL lose efficiency. Not sure if the bacteria die off, or if they go into a state of hybernation, but they don't convert ammonia and nitrite like they did before.

The ammonia spike in your tank will tell you that, and it seems to take several weeks to recover efficiency, just like a tank going through a normal cycle.

If for some reason you need to have your filter turned off for an extended period of time, take out the filter media and put it in a bucket with an airstone. Toss in some fish food, and as it decomposes it will provide ammonia, which will keep your bacteria colony functioning.

[mistakes r crucial]

That is an excellent question and quite ironic as I am in the middle of reading a book kindly sent to me by our suppliers of NatuRose/natural Astaxanthin.

In one of the chapters and I quote, "bacteria go through stress which can be due to a combination of things such as the absence of water, intense sunlight, heat or even bitter cold. It asks, "Have you ever seen a bird bath in summer that has dried up? Sometimes you'll see a redish colour where the standing water has evaporated? The red you're seeing is Astaxanthin. What has happened is that some green algae has suffered stress. As a result of this stress the algae's cells have hyperaccumalated the red pigment Astaxanthin. They do this as a survival mechanism - the Astaxanthin serves as a "force field" to protect the algae from lack of nutrition and/or intense sunlight. It is an absolutely amazing fact, but due to the protective properties of Astaxanthin, these algae can stay dormant for more than 40 years without food or water" unquote.

That wasn't a typo, 40 years!! Now I'm no scientist or vet, I'm nowhere near that well educated but it seems to me that there are far more questions than answers when it comes to bacteria and how they live.

My personal experience with tank filtration is pretty much the same as Mel's but some of this stuff really does ask quite a few questions. If someone comes up with the answers please let me know, it'll save me reading quite so much!
MAC

[ozarowana]

We routinely store E. coli at -80C in a 15% glycerol solution.

[fiftycal]

I was just at Fishrock, and I was told that the Sera bacteria product thingy (I forgot the name), that you add to start up your filter, works very well. If this is the case, then it supports the bacteria not dieing, as the bacteria is alive within the bottle and at a relatively suitable temperature. However, the specific bacteria in the bottle are likely to be of the same species, and the contents may prevent the bacteria from utilizing any other energy sources.


With regards to the canister filters smelling foul and not utilizing ammonia and nitrite, perhaps it is possible that they reverted to a different substrate, so it would take a while until they revert back to ammonia, hence the spike? I am quite sure that they wont die, however their conversion to anaerobic pathways and utilizing other substrates may not be too good...

I will try and find some journal articles in a sec, and I will summarise my findings

[mistakes r crucial]

Mmmmmm.
MAC

[fiftycal]

Hmmm,

We have to consider both the nitrifying and the denitrifying bacteria. This may complicate things as there are now 2 different substrates that have to be looked at, which increases the number of types of bacteria.

[fiftycal]

If you are new to reading journal articles, use this as a guide:

Abstract: Short summary of everything in the article
Introduction: Background of the research and why they are doing it
Materials and Methods: How they conducted the research (you can skip this)
Result: What they found out (usually good)
Discussion: Why they got the result, etc



So far I have this:

http://aem.asm.org/cgi/content/full/67/12/5791

A good start.

"Sequencing revealed that the general clone libraries contained bacteria belonging to a number of bacterial phyla, including the Proteobacteria, Cytophagales, Actinomycetales, low-G+C gram-positive bacteria, Acidobacteria, Nitrospira, OP11, green nonsulfur bacteria, and Planctomycetales. The most common clones in each library were affiliated with either Nitrospira or Proteobacteria."

So pretty much, they are either Nitrospira or Proteobacteria involved in nitrification. Nitrospira is a Proteobacteria lol


http://microbewiki.kenyon.edu/index.php/Nitrospira
very interesting. Although it is wiki, it is microbe wiki, so it is referenced but not peer reviewed. What is interesting is that Nitrospira uses inorganic carbon (eg CO2), as well as pyruvate under aerobic conditions.

Using this website, we will conclude that Nitrospira is the main bacteria used in nitrification.


http://aem.asm.org/cgi/content/full/64/1/258
This is a very closely associated journal article to what we are seeking. It is about Nitrospira in freshwater aquariums.


After reading all this stuff, the conclusion is that it is mainly Nitrospira that is involved in the nitrification process (ammonia -> nitrite)

Nitrite->nitrate will follow. After I find out the main bacteria involved in this, I will try and see what happens in aerobic and anaerobic conditions, and what happens when ammonia or nitrite are not present.

Edit: Looks like I made a mistake, It appears that Nitrospira is the one that converts nitritie to nitrate.

New conclusion: Nitrospira and beta-Proteobacteria are involved in nitrification and Nitrospira is involved in denitrification

[mistakes r crucial]

Still Mmmmm. Bottom line is that even though I am/ we are excited by all the new stuff coming through you still can't beat experience in finding out what happens under certain criteria. If it happened to someone breeding and keeping for 30 years or more then I'm more inclined to go off that experience than whatever I read off the web. However, it is still exciting stuff, we all have so much to learn and share.
MAC

[fiftycal]

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=93301
This article shows that Nitrospira does not uptake any carbon source in anoxic or anaerobic conditions, which means that it does not reproduce, but they DO survive.

[mistakes r crucial]

As much as I love the discussion, take your Discus off filtration for 24 hours, turn it back on and see what happens.
MAC

[fiftycal]

What about a wet/dry sump setup? It will still have oxygen, so will remain aerobic. So far, the only possible negative things are for canister filters, where it is possible other bacteria will populate due to the lack of oxygen and abundance of other substrates. The denitrifying bacteria will still survive though.

[lesley]

I have wondered if the bacteria that convert ammonia to nitrate do survive when dried out. I had some driftwood (previously in a tank for acouple of years) that been in a shed for many months, and when I started up a quarantine tank, put it in together with the new fish and got ready for the uncycled tank issues. However, never had any problems. The tank just got up and running, so I figured it must have been the bacteria on the driftwood.