Blog Entry 3

Week 2

This week a beta food pellet was added to the micro-aquarium, to provide the water with nutrients. (McFarland, 2013). The pellet had dissolved into a murky substance by the time I had made my observations, and there were many protozoa hanging out in the area (Rainis and Russel, 1996). While I was observed the protozoa, a dero annelid crashed the party and started eating on the murky pellet water too, dispersing protozoa in the process. The first things I noticed about deros this week, were that they were noticeably larger than last week. I could even see one of them without use of the microscope, and I could tell when he was eating because I would see the dissolved pellet jerk and move around. The second thing I noticed about the deros, were that they have built some sort of protective covering around their bodies using what seems to be debris found inside the aquarium. They have just constructed this covering within the last week and they retreat into the tubing very quickly as a response to noise or vibrations on the tank. I managed to get a pretty good video of the largest annelid eating and moving within the aquarium (Figure 3). A few things to look for in the video, is its spiked interior that comes out of the back of the tubing. This is how we can identify it as a dero (Rainis and Russel, 1996). It is also interesting to observe the dero's movement pattern. The type of crawling movement that is being displayed here is called "locomotion" (Rainis and Russel, 1996). The rest of the aquarium, was pretty much the same as before, with the exception of there being a few more dead stentors in the bottom layer. I am excited to see how the deros and other organisms develop before next week's observations.