The Secret Life of Microorganisms: Changes to my MicroAquarium on 11/3/11

While looking at my MicroAquarium this week, I found the ecosystem appearing slightly different. The plants did not look as healthy. Upon further inspection, I saw that the Euchlanis sp. and Euplotes sp. populations has increased dramatically. Around every plant stem and bladder, I could see these organisms feeding on the organic material and quickly moving from one area to the next. These aquatic creatures seemed to favor the Amblestegium sp. moss more than the Utricularia gibba L. flowering plant. The Amblestegium sp. moss had grown spike-like filaments that emitted from its bladders, while the Utricularia gibba L. had grown brown, hair-like filaments from its stalk. I saw fewer Vorticella sp. this week, which led me to believe that the Euplotes sp. and Euchlanis sp. were outcompeting them. I observed a slight increase in the nematode population, but exact numbers present in my MicroAquarium were only around 3 to 5 individuals.

To my surprise, I encountered an extremely large, red creature while looking under the microscope. I could also see this organism with my naked eye. Dr. McFarland identified this creature as a midge larvae, Chironomous sp. (Figure 1). Using a text titled Fresh-Water Biology, we saw that this midge resembled Image number 1384 on page 915. It had created channels in the Amblestegium sp. moss by consuming the moss's inner vascular tissue. It was so large, that when is wiggled around, it would move the entire plant. Information gathered from www.mosquitoes.org/Midge.html indicated that midge larvae are often called blood worms and are commonly found in muddy river bottoms of large rivers, which corresponds to my water sample because it came from the French Broad River. This midge larvae moved faster than a worm, and it also used a frontal appendage to pull itself along.

Dr. McFarland and I also identified a new inhabitant of my MicroAquarium, a Tachysoma sp. (Figure 2). According to Dr. McFarland, this particular Tachysoma sp. was unusually large because it was about to divide. A special feature of this genus is the well-developed, immobile dorsal bristles (Patterson 1996).

The next new organisms that I encountered were the Navicula sp., the diatoms (Figure 3). They looked like yellow pellets that hovered over the soil surface. Diatoms are often found in great numbers in small areas, which relates to their abundant populations in my MicroAquairum (Raven and others 2005). Diatoms are also a major food source for many aquatic animals (Raven and others 2005).

I also encountered a puzzling mystery while viewing my MicroAquarium. I noticed a yellow mass that was suspended above the soil surface and looked similar to the diatoms. Upon closer observation, I could see that this mass was made up of individual organisms that were yellow with large, blue centers (Figure 4). I asked Dr. McFarland if he knew what these organisms were, and he said that he was not sure. After doing some research, we concluded that the closest genus we could compare this organism to were the "Plasmodiums." In the future, we will hopefully be able to more accurately identify this organism, but for now, they will remain a mystery.