Week Five

When I picked up my Microaquarium last week I immediately noticed how it lacked water, and I was interested if this had any effect on the organisms. I also wondered if this has exaggerated my thoughts of how much of a population increase there really has been, since the organisms may just be running out of room. Yet, despite my second thoughts, when I looked into the microscope there is no denying the fact that the organisms, especially the seed shrimp, are reproducing at an alarming rate. As each week passes the numbers of ostracods looks like it doubles. The most diverse location in my aquarium now looks to be the soil resting at the bottom, instead of both plants as it was in recent weeks. I hypothesize that the amount of organisms in the soil can be attributed to the large amount of dead matter and waste that make up the sediment. One type of rotifer I identified was the Philodina rotifer, and I recognized this fairly quickly due to the two, wheel-like, spinning trochal disks this species uses for feeding. I watched this organism closely for a few minutes, and noticed how these ciliated appendages can be retracted and released by the rotifer. Despite my captivation with this particular organism, I wanted to further examine the soil and get numbers on seed shrimp inhabiting this area. I followed the soil with my microscope on 400x for the whole length of it and counted thirty seed shrimp, and I also noticed with surprise that the unidentified larvae from previous weeks was feeding deep in a layer of soil. The pellet-like diatoms have not grown at all from their tiny size but they still seem to be numbered in the thousands, and I am interested if they are at the beginning or end of their life cycle.