4th Observation

During my observation this past week I discovered that my micro aquarium was almost completely different from the first day I observed it. There were a few new organisms, but mostly the previously existing organisms themselves had changed considerably.
The annelid that I had stumbled upon on my second observation has not only reproduced again since last week when I had observed two different ones in contrast to the one that I saw the second week, but it also was found outside of the muck, which was the first time I had observed that since the first week. The annelid was around plant B and was feeding off of the algae growing on it. The annelids that still remained in the muck were around the edge and on the verge of coming outside of the muck.
Last week I had placed another food pellet in the aquarium, but this time instead of placing the pellet around plant B I placed the pellet around plant A. My theory for doing this was to see if by placing food around plant A would draw more organisms over to the plant. In the first two weeks all the activity was mostly around plant B. This past week since I had placed the food pellet on the opposite side of the aquarium where all the activity was, the organism moved to that side of the aquarium. The second observation I had, there were tons of vorticella surrounding the pellet. This past week when I placed the food pellet on around plant A, the vorticella left plant B and moved to the other. The vorticella completely left plant B and were all on plant A whereas the week before it was just the opposite.
I noticed that there were a lot of algae in the aquarium, the easiest to identify was the spirogyra (Smith 299-300). The spirogyra was around both plants and I could tell by stalks with what looks like green spiral staircases. Both plants were full of algae, but plant B had the most. I couldn’t identify what the alga was, but it was very thick and could be seen by the naked eye. I am curious as to whether the increase in algae on plant B is due to the lack of activity and organisms surrounding it. The organisms feed off of the algae, and since they are no longer around plant B, the algae will eventually begin to back up, which is what I believe is start to back up.
There were a few new organisms that I was able to identify during my observation period. The most interesting one was a new rotifer I located which was the Collotheca Rotifer. This rotifer has cilia around the opening of its mouth and when disturbed, it coils up and closes. It is a slow process when it comes back out, but it will slowly inch forward and then once it is fully stretched out, it will open its mouth. I watched it eat several organisms, its prey is protozoa and rotifers (Stemberger 44-45) and it makes a similar movement like it does when it is disturbed except it does not curl up. It closes its mouth slowly trapping its food inside. Another interesting organism was the cyclopoid naupluis (Smith 490), which is a spider like organism. I didn’t get to see the organism move, so I don’t know its movement, but it is a transparent looking organism with spider like legs. I saw two different amoebas, the first I couldn’t exactly identify it, but I know it is an amoeba that forks by its forking movement. The other was a difflugia amoeba which looks almost like a hermit crab (Patterson 96). It creates a hard shell out of pieces of debris and it has little arms at one point it has three different arms and then changed to two but it can change the number, size, and shape of its arms.
This week I did not add a food pellet, but I did add water.
Work Cited:
Smith, Gilbert. Freshwater Algae of the Unites States. 2nd. New York: McGraw Hill Book Company, 1950. 299-300. Print.
Stemberger, Richard. A Guide to Rotifers of the Laurentatian Great Lakes. 44-45. Print.
Patterson, D.J. Free Living Freshwater Protozoa. London: John Wiley & Sons, Inc., 1996. 96. Print.
Smith, Douglas. Pennak's Freshwater Invertebrates of the U.S.. 4th. New York: John Wiley & Sons, Inc., 490. Print.