Perimeter detail of ring at 100x ( phase contrast )
Possible Bacteria Swarm Ring
I am currently studying the diversity of protozoans and metazoans in
water from my rain barrel and keep small sample jars of water and specimens
that I collect.
Over time the populations change as some species disappear entirely while
other species momentarily bloom and flourish. In one of my jars I let the
water gradually evaporate down into a watery sludge in the bottom of
the sample jar. Tonight I examined slides under my microscope
and witnessed an eerie quietude with minimal protist activity where
there had always been bustling activity. Through the microscope at 100x
using the phase contrast method I noticed a superactive ring of bacteria
coalescing, getting denser and in dynamic motion. The ring was unbroken
around the span of most of the cover slip. I made four different slides
and each slide duplicated this interesting ring phenomenon.
: ring perimeter in motion, real time 26 seconds
1.7 Mb movie ( click image to play )
: rotifer, possibly feeding at the ring
25 seconds 1.7 Mb
(click image to play )
: bacteria in motion at 1000x brightfield
11 seconds 819 Kb (click image to play)
Update : My initial impression of this intense ring of bacteria
was that this might be a predatory strategy by the bacteria themselves.
The slide was littered with metazoan carcasses. Upon further dialogue
and reading, it appears that my specimen jar became oxygen deprived due
to an imbalance
of too much organic matter and not enough oxygen exchange. The higher
"animals" like Chaetonotuses might have died due to lack of oxygen and not
And it is also possible that this bacteria ring itself was oxygen related
under the cover slip. I hope to learn more and update this page with
further observations in time.
Any comments, corrections or elucidation on
this phenomenon is most welcome.
Meiji microscope and objectives
Canon S3 IS camera