Week 4 Observation

            This week I made my observations on Wednesday November 6, 2013. I noticed that the number of living organisms had dropped since last week when the food pellet was introduced. The habitat seemed to have slowed down and things were beginning to deteriorate and die. The leaves are beginning to brown in areas and look as though they are being fed upon. The aquarium contained floating debris and many semi-transparent glob structures, possibly egg sacs, that were to be located along the leaves where diatoms may have previously been attached. 

            Although, my aquarium seems to have slowed down with organism activity, I have noticed a few new species. One of the new organisms I was able to is an insect larva. The organism would pull itself around at a steady speed that was not very hard to keep up with. The organism has hair like appendages along the side of its body and uses arm appendages to pull it around and eat. You can see the organism’s eyespots in Figure 1. The organism stayed on and around the leaves of the Fontinalis sp. and seems to be feeding on the leaves. The organism is a darker brown color and does not contain any chlorophyll.

Figure 1: Insect Larva
Photo by: David Colvin

Another new organism I observed in my aquarium was a small blue green one that seemed to glide smoothly through the open water. The organism moved very quickly and was difficult to follow for more than a few seconds. The organism seemed to have some small hairlike appendages that ran the length of its body and had a forked tail at the tail end as seen in Figure 2. I identified this common freshwater organism as a Gastrotricha chaetonotus (Thorp and Covich, 2010). 

Figure 2: Gastrotricha chaetonotus
Photo by: David Colvin

This week I observed an organism called a Philodina rotifer (Patterson D. J. 1996). The organism was very slow and had a brownish transparent color. It stayed in generally the same area on the Fontinalis sp. leaf and stretches out and contracts. 

Figure 3: Philodina rotifer sp.
Photo by: David Colvin