What happens to dead Beneficial Bacteria?

[JackEmerson]

This weekend, we had an electrical issues and one of my filters lost power for a while. My tank has two filters, and only one was affected, so there was no real loss to the tank as a whole. My filter (a HOB) was pretty dry by the time I realized it. Which made me wonder what would happen if I just turn the power back on: would a bunch of dead BB be poured into the tank and cause a greater problem? I was not able to figure it out, so I just used it as an opportunity to replace the filter media that dried out.

So my question is: if a BB dies on a surface/media and then water flows again, is that dead BB harmful, or should it not be worried about?

 

[Hendre]

I doubt the biomass is enough to worry about.

 

[jjohnwm]

I wouldn't be concerned about dead bacteria impacting water quality. In fact, based entirely upon anecdotal evidence and my own experience, I believe that a dried-out sponge filter will develop a mature bacterial population much faster than a clean one; dormant bacteria? Don't know, but that's my theory and I'm stickin' to it.

A related concern is the possibility of a sponge or media remaining wet, and possibly developing a growth of anaerobes resulting in a black, smelly mess and the production of hydrogen sulphide gas. I know numerous websites tell us that is a concern...and numerous others claim it's impossible. I'm no scientist, but if you doubt it then take some dirty aquarium and half fill a bucket, top up with water and leave it on the floor for a couple months. Sometimes...nothing happens. But other times, all kinds of nasty processes take place, the gravel and bucket are stained a permanent blackish colour....and you definitely don't want that gas...whatever it is...in your fishtank. This would take weeks or months, not just a few hours.

I'll take dead beneficial bacteria over live inimical bacteria any day of the week.

 

[TwoHedWlf]

The actual total mass of the bacteria is probably far less than you feed daily. It would rot, produce a little ammonia and then feed the survivors, likely not even causing a blip in the ammonia levels.

 

[FJB]

Depending on the length of time without power, not all the bacteria may have died. Also, with power shortages of just a few hours, usually little or negligee able bacteria mortality should occur. Longer shortages, is another story. Regardless the bacteria in the old media would certainly repopulate faster than in a new batch of media. Also, why would the media have completely dried out? What kind of filter? Above the aquarium so it drained out?

 

[Backfromthedead]

I consider all of the beneficial bacteria residing in a tank a collective entity that is constantly interacting with its environment. Its important to remember there are many varieties of nitrifying bacteria colonizing your filter media, not just one or even three, that are all working in coordination to balance the nitrogen cycle in your tank. The waste from one bacteria feeds another and on and on it goes. In the sense of what jjohnwm is saying about dormancy above, i would say that dried out, dirty media still contains many of the different waste compounds(food) needed for the various types of nitrifying bacteria to propagate, which is why old dirty media will indeed colonize much more quickly than clean new media.

In summation...the dead bacteria is processed with the rest of the waste in the tank. In your example i would probably just lightly rinse out the media with tank water and expect maybe a bit of mini-cycling haziness over the next couple days.

This is an altogether different issue with canister filters. Ime it seems like the dark confines of a stagnant canister filter can produce toxic levels of hydrogen sulfide in just a few hours of being left off if its dirty enough, so never plug one back in before cleaning it out thoroughly if its been off awhile. I dont think this would be a big issue with hang on filters though.