I hate to disagree...
Never be afraid to disagree! This whole site is about debate, discussion and learning from others. In fact, we should probably be having this discussion in that thread so that others can read/learn/participate.
(an assumption I'm making here: H2S = Hydrogen Sulfide)
I don't have the biology background you do so I can only pose questions to you relating your statements to my experience and the anecdotal evidence posted here and on other sites. So, lets discuss...
I agree with you 100% that the bacteria is there "For a reason". In fact, thats why we cycle a
SW tank, to give the bacteria a chance to populate the substrate, rocks and any other filter media the tank may be set up with. We do this because that's how the ocean handles waste and it is the most efficient and balanced way to handle it in an aquarium as well. Since the seafloor is merely an extremely large "
DSB" it is only logical to assume these bacteria, of all sorts, reside there as well. They are quite common in many very active and very well established aquariums. if you do an
image google for refugium you can see in a number of photos that the bacteria is common place.
IMO, it is also necessary, not to mention, would be impossible to prevent from occurring, unless you had no substrate at all.
So if the bacteria is an entity that will be in all aquariums and is in the ocean naturally, why do some people have sudden crashes after noticing a sulfur smell? From the reading I've done (on this board and others over that last couple of years) there appear to be a lot of common factors, but not always. A healthy and active live sand bed will have the following:
Bacteria: as we know, these process the various waste materials at different stages.
Flora: algaes that populate the top most surface of the sand bed
Fauna: copepods, snails, worms, etc that inhabit the sand bed.
As I'm sure you know, any natural system that is taken out of balance will eventually fail if not corrected. These DSBs that crash seem to be sand beds that have fallen out of balance.
IMO, the most important element of a sand bed (short of the bacteria itself) is the Fauna. These creatures are really the caretakers of the sand bed. Without them a lot of hobbiest notice "clumping" of the sand as the bacteria also produces something (I don't recall the actual name) that dissolves the calcium carbonate (CACO3?) and causes the sand to glue to itself. This is because the fauna is not there to consume the bacteria and its byproducts. My theory is that after the fauna have been reduced, the sand begins to clump and it is not longer being "stirred" by the fauna to release the extra H2S as its produced so the gas begins to build up. Then something causes a sudden release of the H2S, either the owner bought a fish that is disturbing the sand or they move the substrate around or the rock, etc and the gas begins to release itself into the water in high volumes (or the gas has simply built up enough large pockets that it begins to release itself through the sand bed).
We know that high levels of H2S is toxic and will decimate an aquarium. So what causes a loss of the fauna? More often then not the aquarium has some sort of "sand sifting" creature. A Satrfish, horseshoe crab, etc, that eats the fauna in the sand bed (that's why they "sift" the sand, they're looking for food) so people think they're helping their sand bed by getting these creatures when they are in fact hurting their sand bed. The fauna will stir the sand as much as it needs to be. So these starfish and horseshoe crabs exist in the wild, why would they upset the balance in an aquarium? Well, the biggest difference
IMO, is the fact that the ocean has acres of sand full of fauna to re-populate the eaten areas and an aquarium does not. So once the fauna is gone, the sandbed is doomed unless it can be repopulated (garf grunge, etc).
It just so happens that in the case of anaerobic bacteria in a marine environment, the majority of them will either produce or utilize H2S in their routine metabolic functions.
I figured as much, I just didn't have the book learnin to back it up So if some produce H2S and others consume H2S, it would make sense to say you want an equal amount of both types of bacteria in your sand bed to keep both the waste and the H2S in balance, correct? Because, "everything is everywhere, the environment selects..." the bacteria that produces H2S must come first so that the bacteria that consumes H2S can begin to co-habitate the sand bed and balance the system, right?
So what are the differences between these two types of bacteria? got any more details? I'd really like to add that info to my theories. I'm sure there's some holes in my theories and I look forward to you pointing them out!
Please don't take this as an insult or a flame
I am not insulted, nor do I consider this a flame. We progress only by research and the debate of the observations of that research.
