Week 4 Observation

This week I made my observation on Wednesday, November 12. There were some interesting things happened in my aquarium this week. Some of the missing organisms had reappeared and the number of organisms in my aquarium had increased. Cyclops disappeared two weeks ago had reappeared in the tank, I found 4 of them this week. Tiny shelled rotifers were still increasing in number. I also found about 7 gastrotiches and 5 nematodes. I was assuming that Plant B had consumed all the missing organisms, but that was not the case for the most part. I asked Dr. McFarland about the missing organisms, he told the microaquarium is a portion of the ecosystem. Every organism in the aquarium is part of the food chain. Plant B did consumed some of the bigger organisms, but not all of them were consumed by it. The larger organisms consumed the smaller ones. Eventually, the larger organisms ran out of food and died. The population of the organisms will go up and down like a roller coaster. This is happening because we disturbed the ecosystem when we extracted these organisms from their natural environment. The food pellet was added after the first week also upset the balance. The system would eventually come to a balance by repopulating the aquarium. That is the reason the number of organisms in my aquarium started to increase again.

List of organisms found:
Cyclops - 4
Gastrotrichs - 7
Nematodes - 5
Shelled rotifers - several

Below are the pictures of aeolosoma and gastrotiches.

Week 3 Observation

This week I made my observation on Thursday November 6, 2008. The water level in the tank was significantly lower than the first day it was set up. It's about 3/4 of the water left in the tank. The bacteria in the aquarium increased as usual. There seem to be less activity in my aquarium than last week. The orgainsms in my aquarium also seem to be getting less and less. Most of the non-stationary organisms in the tank are larvas and embryotic organisms. My assumption is that Plant B (Utricularia vulgaris L.), a carnovious plant I added to my tank, consumed most of the non-stationary organisms in my aquarium. The organisms I found that were left in my aquarium were several green algaes, 15 coleochaete, about 10 nematodes, about 10 daphnia, 3 gastrotrichs, and about 20 shelled rotifers larvas crawling along the plant roots.

List of organisms found:
Coleochaetes - 15
Nematodes - 10
Daphnias - 10
Gastrotrichs - 3
Shelled rotifers - 20

Below are the pictures of coleochaete and gastrotriches.