bacteria viability in cold water?

[Sploke]

I think I read someplace that when it gets very cold (ice on the surface, 39*F on the bottom), the beneficial bacteria that lives in the filter does not survive, therefore it wouldn't be necessary to keep the filter running all winter long. Has anyone else heard this or have anything to back it up? I would be a fan of not having to clean out my prefilter in the dead of winter.

[finsNfur]

I don't know if that's true or not. However, the first winter of my pond I shut off the pump and filter for the winter. BY early spring I had pea soup in the pond, and the filter was a gelatinous mess of green yuck. Last winter I kept the filter and pump on, and I had much less algae and green stuff by spring.

[Sploke]

The past two years, I have left the filter running. When the fish stop eating, I get about 6" of hair algae covering the whole bottom and sides of the pond, but I think the water is too cold for the suspended algae to grow, because I turn off my UV sterilizer in the winter and the water doesn't turn green.

[H3D]

I think the bacteria will survive as long as it doesn't get frozen, especially in the substrate where is is warmer.

[Sploke]

Well to answer my own question, looking at some bio texts, it looks like Nitrobacter spp. and Nitrospira spp. will both survive down to about 5*C, which is about as cold as the water at the pond bottom will get.

The other limiting factor however, would be food source. Since the turtles hibernate and the fish go dormant, no one is eating, so therefore I would think a minimum of ammonia would be produced, thereby severely restricting bacterial growth in the filter.

[dixienut]

Well to answer my own question, looking at some bio texts, it looks like Nitrobacter spp. and Nitrospira spp. will both survive down to about 5*C, which is about as cold as the water at the pond bottom will get.

The other limiting factor however, would be food source. Since the turtles hibernate and the fish go dormant, no one is eating, so therefore I would think a minimum of ammonia would be produced, thereby severely restricting bacterial growth in the filter.

well that was what i was going to say but you beat me to it,......

[wataugachicken]

i think there is a difference between them dying and simply going dormant (duh, of course, when i say it that way). but what i mean is if a pond is warm, but there is no food, the bacteria will die off. if it gets cold BEFORE they die off, they will go dormant, just like the fish and turtles. when it gets warm enough for them to wake up, they will eat. i mean, this is how bio-spira works. it has to be refrigerated because the bacteria inside are dormant, if it warms up and there is no food they will die. but as long as they are kept cold, they don't need to eat and so they won't starve.

[THE V]

Actually almost all bacteria will go dormant first when they lack food regardless of temperature. At warmer temperatures they have a certain amount of time before they start to die off (usually a week or so). At colder temperatures this time is extended for months (if not years) because of the bacteria's greatly reduced metabolic needs.

[Reddog80p]

Interesting...I could have swore that I read somewhere that all beneficial bacteria dies at a certain temperature.

[Reddog80p]

The reason I keep my pumps and filters off is water temperature. If your pulling the warmer water off the bottom through your pump/filter and out off a waterfall the water will be the same temp in all levels of your pond. If you simply run a de-icer and/or a bubbler about a foot under the water surface the warmer water at the bottom of your pond will not be disturbed. Neither will any debris on your ponds liner.

[THE V]

Interesting...I could have swore that I read somewhere that all beneficial bacteria dies at a certain temperature.

You did at 0C... It's a myth floating around on pond and aquarium sites. Nitrifying bacteria are actually very hardy. They can exist for long periods of starvation, dryness and adverse conditions. They just take some time to bounce back after prolonged stress. Here's a fun little article talking about permafrost and exobiology. :)


Nitrifiers exist in most aerobic environments where organic matter is mineralized
(soils, compost, fresh- and seawater, waste water). In general, cell growth is slow with
regard to the poor energy sources but can be adapted to changing environmental conditions.
Especially for Nitrobacter, mixotrophic and heterotrophic growth with organic
compounds is an alternative to the oxidation of nitrite. Nitrifiers are also active in low
oxygen and anaerobic environments like sewage disposal systems and marine sediments
where they are able to act as denitrifiers [34]. Although they form no endospores, they
can survive long periods of starvation and dryness. Therefore, nitrifying bacteria were
also detected in e.g., antarctic soils [35], natural stones [36], heating systems [32] as
well as in subsurface sediments in a depth of 260 m [37]. Especially ammonia oxidizers
form dense cell clusters, where cells are embedded in a dense layer of EPS (extracellular
polymeric substances). These microcolonies may protect the cells against
stress factors like dryness. Another protecting mechanism is the production or accumulation
of compatible solutes (e.g., trehalose, glycine betaine or sucrose, see Chap.
12, Kunte et al.). Due to salt stress and dryness an increasing amount of compatible
solutes was found in cells of Nitrobacter [38].

http://epic.awi.de/Publications/Wag2001a.pdf