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Robert Paul H. wrote:
> I was
> reading some material about photosynthesis, and it was discussing a type of
> bacteria that photosynthesises hydrogen sulfide instead of O2...I forget the
> name of the bacteria, I'dhave to check my notes...wait here it is,
> archaebacteria: mud dwelling bacteria releases rotten egg smell when
> releasing sulfide instead of oxygen. Is this bacteria present in aquariums
> when we have a sulfide build up?
Probably not. Archaebacteria are found here and there but if I remember
my reading correctly they are only common microbes under very extreme
conditions -- thermal vents on the deep ocean floor, boiling mud springs
and other places that kill all normal life.
The bacteria that produce the rotten-egg stench under less extreme
conditions are common non-photosynthetic sulfate-reducing critters.
Their metabolism is fairly normal; they obtain energy by oxidizing
carbon, for which they need an electron donor. Aerobic bacteria use
oxygen to provide the electron, but sulfate-reducing bacteria use
sulfate. They produce reduced sulfur compounds, including hydrogen
sulfide and some sulfur-bearing organics, and it's those products that
There are also photosynthetic normal (non-archae...) bacteria of various
sorts. They generally live under very subdued lighting and are brightly
pigmented. I had some "stuff" growing with one of my sword plants that
grows emersed out of a fish bowl half-filled with substrate. A bright
pink growth developed on the bottom of the bowl where sunlight was
refracted in along the bottom glass and along the sides 90 degrees away
from the window that provided the light source. When I rotated the bowl
so the pink part faced the window, it died out and a new colony formed
90 degrees away from the light.
I think the pink stuff was a photosynthetic bacterium, but most likely
not an archaebacterium. The colonies finally disappeared after I tipped
the bowl sideways to allow it to drain and left the colony exposed to
the air for 10 or 20 minutes. Oxygen is highly toxic to any obligate