Final Observation

Since last week:
     
     After my viewing time in the lab last week, I added a few drops of distilled water to my aquarium which it had lost to evaporation.


Observation

     The total amount of life in the aquarium has dropped back to about where it was in Week 1, but it's a very different scene than it was then. Cyanobacteria and green algae (which I identified from my Botany 111 course lecture and lab) grew to very large populations, especially the cyanobacteria, and now can be seen at almost any point in the tank through the microscope.

     The diatom population also grew quite rapidly after the food pellet was added. This week, many dead and broken diatom shells litter the bottom half of the tank, even though there are still many more living diatoms this week than in the beginning. I have included an image of some diatom species in my tank (the small egg-shaped organisms clinging to the cyanobacteria are also diatoms, identified by Dr. Mcfarland.)

    











Newly observed this week were several Difflugia sp., identified from Free-Living Freshwater Protozoa, D.J. Patterson on p. 95, fig. 186. It has a tall lightbulb-shaped shell that is rough in appearance. Difflugia is an amoeba that makes this shell from its environment. It moves by extending amorphous "legs" and looks kind of like a snail in its speed and motion. These protozoans were mostly in the middle of my tank, with many flagellates eating from its shell.

     Here is an image I took of one of my Difflugia sp.

     I observed more Lacrymaria sp. this week, fewer flagellates, and some Halteria sp. Also Identified from Free-Living Freshwater Protozoa. On my last scan through the tiny habitat I noticed a little organism with one "leg" stuck to a plant, with two clusters of cilia on its main body. This is a Vorticella sp. (p. 13, Ciliated Protozoa, Hartmut Bick, 1972).             I thought this little guy was pretty adorable,   just floating there with his cilia clusters spinning like little helicopters.

Thank you all for reading my blog, I had a lot of fun observing and reporting on my tiny habitat. 

Don't drink the water!!!

-Jon
 

Observation #3

Observation

      Last week, after the food pellet was added, I observed rapid growth of the population in my aquarium. Many more organisms were present, resulting in higher competition, which has led to many more dead organisms in the tank this week.

      I've identified my clear, long, worm-like creatures as Nematodes. I haven't seen the carpenter's ruler colonies in the past 2 weeks, but many more diatoms altogether. I observed small ellipsoid-shaped diatoms stuck to some root-like plant structures, as well as more of the square diatoms I described last week. My water sample is full of cyanobacteria colonies, I was unable to identify these until this week, but the species looks like Oscillatoria; hairlike structures that twitch and move slowly and smoothly. I took a video of a Lacrymaria sp. near the bottom of my aquarium, identified from the book Free-Living Freshwater Protozoa, D.J Patterson, 1996, p. 138, figure 301.

      The Lacrymaria is the amorphous organism I described last week, one can see from the video how it moves. The contracting and expanding of the vacuole in its posterior makes the organism able to extend its "neck" and "tail".

I find the mechanism of motion very interesting, but also slightly repulsive. But Dr. McFarland eased my nausea by informing me that there are unicellular organisms like this inside my own body...