Week 8: Continuing pHstat Experimentation

Once again I began the week by preparing for a 24 hour biotic run on the pHstat, using the pH gradient Labview program instead of the pH set point program. This program also needed to be tested in triplicate with the same times and type of sampling throughout the 24 hours of experimentation. I started the first experiment on Monday and it continued till Tuesday. All of the data was collected and processed on Tuesday. During my downtime between sampling points I continued to process the previous data and any maintenance needed around the lab. For the rest of the day on Tuesday I continued to process the data from the runs finished at that point.

                We finally received the DO cap earlier in the week, so we began the sparging experiment. The cultures were prepared the previous week to increase the biomass to an acceptable level. For this experiment I needed to measure the oxygen content of all the cultures when I first arrived and then use nitrogen bubbling on the three cultures that were low oxygen conditions. Unlike many batch cultures these bottles needed to be shut during experimentation to maintain a low oxygen environment. To compensate for the lack of a carbon source I would add a specified amount of sodium bicarbonate to the culture to continue a healthy growth. During the sparging, the culture was lowered to around 30% oxygen content. It was hard to balance the container while bubbling and a sample was taken to observe the biomass of the culture through cell counts. It was extremely interesting process and it was interesting to observe the effects over a shorter period of time. However, by the end of the week we discovered that the experiment was flawed and the data would need to be redone in order to receive reliable results.

                Wednesday we took a trip out to Astoria to observe the sample points within the estuary. We observed the data collection by a machine being lowered into the estuary in real time as we were out upon the sampling boat. This was extremely interesting and the machine also measured the depth so that as they were lowering it into the estuary. They used this measurement to make sure that the machine did not hit the bottom of the estuary during the data collection. I had an amazing time on the boat again. Afterwards we tried to look around the museum, however the museum was closing in a half an hour so we just went for ice cream and headed home.

                The next day I started yet another 24 hour biotic experiment using the pH gradient Labview program. This run being the third one that we needed for triplication. All of the parameters and sampling points were the same as the previous experiments. During this time I prepared for the following week without Rachel. Mostly I continued lab maintenance, transferred the weekly cultures and even continued data processing for the already accomplished runs. There was a lot of work ahead of me in the following week.