Fourth Observation - Part B

I did my fourth and final observation on Wednesday, November 16, at 10:00 a.m. Today, rather than taking pictures of specific organisms, I scanned the entire tank to see what the overall activity looked like and which organisms could be found in which areas.

This was definitely the most active of all of my observations, so perhaps my assumption that the population levels were dropping last time was incorrect.

I didn't see any nematodes, but there were several Chaetogaster sp. in the soil layer (which I'd previously observed and photographed). The bottom third of the tank was also covered heavily in cyanobacteria, which had always been present but now had become so populous that this area of the tank appeared very green when not under the microscope.

Moving up in the tank, there were many more Actinosphaerium sp. than I'd previously observed, including one that was in the process of dividing.

Other creatures that I saw in the middle area of the tank, which I'd previously observed and classified, were Childonella sp., a Vorticella sp. using its cilia very actively (though not moving quickly), and Epalxis sp. There were also huge numbers of organisms too tiny to see clearly or classify.

Still in the mid-tank region, around the plant Amblestegium sp., was a mass of Colpidium sp. in what appeared to be a breeding ground for that particular organism type.

There were very many diatoms in the top region of the tank. I also spotted a small number of Bursaria sp. and, at the very top, several Chlamydodon sp.

All of the above organisms had been previously observed and keyed. I also saw two organisms that I had not previously observed: Cyclidium sp. (who was living amongst the mass of Colpidium and was indeed being jostled around by them), and Entosiphon sp., both of which were keyed with the use of D.J. Patterson's Free-living Freshwater Protozoa. And additionally, there were other familiar organisms whose names I could not remember but had seen before.

Since this was the end of my experiment, and I'd become rather fond of the bizarre little microworld in my tank, I asked to set my organisms free in an environment where they might thrive rather than sending them to a supposed watery death at a water treatment plant. Dr. McFarland obligingly allowed me to empty my MicroAquarium™ into one of the greenhouse tanks. Live long and prosper, my single-celled friends.