I collected my soil sample from the lawn in front of the Nott on campus. I dug down about an inch and then filled my test tube with soil and tried to avoid getting grass in it. The GPS coordinates were 42.8173 degrees N, 73.9300 degrees W.

I chose this location because I was interested in seeing what kind of bacteria was growing there since many students sit on the lawn in front of the Nott when it is nice out. I also wanted to see what was there because I know that lawn is constantly treated to keep up its appearance.
I do expect a lot of isolates because the lawn is treated so much that it makes it rich and good for sustaining the growth of the lawn and also bacteria.

So far this has been reflected on my culture plates. There has been a lot of growth and even a lot of overgrowth on most of my plates including the plates with less concentrated dilutions. I couldn’t count any of my plates from my first round of plating because they were so overgrown.

I chose to use LB, R2A, and AC for my media. I chose LB and AC because I figured the complex media would reflect their natural, rich environment of the lawn so I was confident I would get growth even with higher dilutions. I used R2A because I wanted to plate a minimal media since I figured the soil was so rich with bacteria that there might be almost too much bacteria to work with.

I plated a zero dilution, a 10^-1, and a 10^-2 dilution on R2A because this was the minimal media so I figured I should test out the more concentrated dilutions. I plated 10^-1, 10^-2, and 10^-3 dilutions for LB and Ac because they were the complex media so I figured the bacteria would grow more easily on this media and a less concentrated dilution would be the best to use.

Since pretty much all of my plates were overgrown and I couldn’t count cfu’s for any of them, I had to replate some dilutions. I replated a 10^-3 dilution on AC and R2A because I thought that if I left them in the incubator for a shorter amount of time before looking at them that I’d be able to count them and pick more isolated colonies and this was correct. I also replated a 10^-4 dilution on LB, AC, and R2A because there was overgrowth on all of my 10^-3 plates from the first round of plating so I thought doing a dilution with a lower concentration that it would be even better work with, however these plates barely had any growth after 2 days.

All three of my media had a lot of growth. I chose the fewest colonies from the R2A plates because those plates had some good colonies but there were a lot of extremely small colonies that were very close together which meant I couldn’t pick individual colonies up very easily. The LB and AC also had a lot of good colonies but they were very overgrown so it was hard to pick individual colonies. The colonies were overall larger on AC and LB and also more diverse.