Life in anaerobic water
Posted @ NImag by
Guy Sawle
Canadian Koi and Pond shares this article with the permission of Guy
Sawle; this article and photographs are not to be used elsewhere with
out first being granted permission by Guy Sawle.
When I was designing my pond I read a great deal about fitting tangential pond returns so I could reverse the direction of flow of the water and avoid ending up with fish shaped like bananas.
But of course reversing the flow is a boring job, because of back-flushing the water which has been stagnant in the non-functioning circuits. So I inadvertently left the job much longer than I intended to.
When I did eventually give the non-functioning return pipes a thorough flush recently the stench of anaerobic water was dreadful. So naturally I collected some in a jug and took tiny quantities into the kitchen to see what (if anything) was living in it.
There were huge numbers of encysted amoebas. And the following.
Here are three views of a small protozoan-sized greature called a gastrotrich. They have cilia and they glide around. They have a complicated gut inside and two sticky structures at the back end.
These are two not-very-good pictures of tardigrades, also called water bears. They are also in the protozoan size range, but are multicellular and good specimens (which these are not) move around in the style of little bears. The one on the left was from the anaerobic water sample. The one on the right is from the small layer of dirt and grit lying in the bottom of my waterfall trough.
One of the most extraordinary things about these creatures is their ability to withstand extremes of temperature and dessication. They can revent to an 'instant coffee' kind of state in which they are able to withstand liquid nitrogen and boiling water. Not sure about potassium permanganate.
Left is (I think) paramecium - favourite protozoan of school experiments. Right is something altogether more peculiar. I have NO IDEA what this is; any suggestions?
Finally, a rotifer (left) holding onto a testate amoeba with its toes, and some further unidentified colourful things on the right, which look like they contain algae. Any suggestions what these are? There were hundreds of these, just as there were hundreds of centropyxis and other testate (shelled) amoeba on every slide I looked at.
You may be wondering how many slides I have looked at to find the creatures I have posted recently. The answer is not many. Most slides have dozens of creatures on them!
Guy
