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Week 7: Altering Experiment

I began the week by checking on the pH drift of the pH meter that had been sitting in a culture over a 72 hour period. Then I once again started a 24 hour biotic run with the pH set point program. This needed to be run in triplicate to assess the consistency of the program. This run also had sampling points at specific times collecting DIC data and the values of chlorophyll within the culture. This run lasted until Tuesday. Tuesday morning I discovered that we needed to redo the last two runs, because the chlorophyll values are not entirely accurate at assessing the concentration of the culture. In order to fix this problem, we added a fixative to 3mL of sample to later count the amount of cells per volume to get a better idea of the concentration of cells in the batch culture.  

                Once again I started the first run of the triplicate set point program on Tuesday. At the major sampling points, samples were taken for DIC, chlorophyll and cell counts. The minor sampling points were only for DIC measurements. Unlike the other two runs, the DIC measurements were no longer triplicated. At the end of the run the pH drift for the pH meter was recorded and the data was combined together to assess the amount of pH drift versus the amount of time passed. I ran the biotic experiment twice more for 24 hours to complete the triplicate data. Just like the first run the samples were collected in a similar manor. After each run was completed I processed the data so that it could be placed in a graph format. After the last run I also calibrated the pH meter to observe the pH drift over a longer period of time than 24 hours.

I was still waiting for the part of the DO meter to be shipped to work before we could start the sparging experiment. However, I prepared the cultures for later experimentation so they could grow to a certain biomass. After looking over the data from the last run of the pHstat, we discovered that this run needed to be redone in order to assess the program and make sure everything was running smoothly. At this point I made a separate culture to assess the pH drift that occurs from the second pH meter. This data was added to the already collected pH drift data. The pH drift data was collected over multiple days to assess the drift over a longer period of time. I then graphed the data collected so far in a bar graph and took a break for the weekend.