Third viewing

On Friday, October 31st, 2008, I viewed my aquarium for a third time. I was anxious to find out what effects the food pellet had. The changes were not as dramatic as I had expected. I examined the food pellet first to see what type of organisms were attracted to it. Having been in there for about a week, it was in a state of partial decomposition. There were swarms of rotifers nibbling on the loose ends. I was casually watching the feast when I discovered a new organism. It had attached itself to the bottom left quadrant of the food pellet. It had a long, narrow, transparent body with what appeared to be two spinning wheels on the outer end. I could also see some kind of organ inside of it, beating like a heart. Occasionally it would catch something with its two wheels and pull them inside of itself in a sort of gulping motion. After a moment, it would spit these two wheels back out and resume spinning them.



I looked at the lab poster and found that this new creature was yet another type of rotifer, but I was curious to find out how many different types of rotifers there actually were and what species did I have. With Dr. McFarland’s help, I found illustrations of my rotifers in one of the reference books. In particular:

Ward, Henry Baldwin and George Chandler Whipple. Freshwater Biology. New York: John Wiley & Sons, Inc. 1918.

From checking figures 958 and 959 on page 618 of Freshwater Biology, my best guess is that this newest rotifer is either a Philodina roseola or a Rotifer citrinus. The two figures look too similar for me to differentiate. I also checked figure 888 on page 592 to estimate that the previous rotifers were probably a type of shelled rotifer called Diplois daviesiae.

After this, I looked around the rest of the aquarium to see in any other changes had taken place. I was surprised to see quite a few of these new rotifers. There was also an increase in the number of epistylis and nemotodes. I also noticed quite a few dead Diplois rotifers in the bottom of the aquarium, and I saw a few trapped in the sacs of the carnivorous plant, Utricularia vulgaris. There was still no sign of the water flea, and I didn’t see any amoebas this time. There also seemed to be less dirt in the bottom of the aquarium, but I could be mistaken. I will have to wait till next Friday to be sure.