Where did you obtain your soil sample?

I decided to collect my soil sample from Union’s Octopus Community Garden on campus. I took the sample an inch or two down, just below the surface, so that I did not get the hard topsoil/mulch and it was near bulbs that were growing (I assumed they were onion bulbs). GPS coordinates- Latitude: 42.8 degrees Longitude: -73.9 degrees.

Why did you choose this location?

I chose this location because I thought it would be interesting to look at something available right on our campus that many members of the community use or partake in on a regular basis. I also expected the soil to be “rich” due to its use in the garden to grow vegetables and various plants.

Do you expect a lot of isolates? Why or why not? 

Yes! I expected there to be a lot of isolates due to the rich nature of the soil being used for gardening purposes. I also thought that maybe because various plants and vegetables grow there that there may be more diversity depending on what has been grown in that location now and previously. In addition, there are a lot of people that work in the garden there that could contribute to what is in the dirt.

Have your initial observations supported this?

Yes, I have a lot of growth on my plates. It seems like I have a lot of growth and a decent variety because many of them look different in their coloring or morphologies. The only countable plates I had were on the 10^-4 dilution plates.

What media did you choose?

I chose 10% TSA, LB, and AC for my three. Prof. Salvo suggested that everyone in the class should use LB for one of the choices. Then I chose 10% TSA and AC because they were for cultivating a wide variety of microorganisms, according to their descriptions in the handout. I thought I would have a wide variety for my soil sample and so I chose these two.

What dilutions?

I plated 10^-2, 10^-3, and 10^-4 dilutions on my plates for each of the three media. (However, going by the way the book does it, these need to be changed to 10^-1, 10^-2, and 10^-3).

Will you need to redo any?

I had growth for all of my plates at the various dilutions, but I decided to re-plate a few. My plates with the AC medium still had too many colonies to count and lots of growth making it difficult to distinguish, so I went one dilution further, 10^-5 (which is actually 10^-4 according to the book) and plated two of these. I am still waiting for these to determine the CFU, but after two days there is no growth yet. I also did one more plate with LB and 10%TSA at a 10^-4 (actually 10^-3) dilution because these were countable, but there were a few large growths and I wanted to compare to get a more accurate CFU. I am still waiting a few more days to get a count because after 2 days there were 2 colonies on the 10% TSA plate and no growth on the LB plate.

How did your sample differ on the different media?

All three had a decent amount and variety on all the different media. AC had the least “pickable” colonies and I was only able to pick 14 (hopefully the new plates will provide more) because mycoides were present as well as really large growths. The LB and a few from the 10% TSA had a very dark brownish pigment sort of radiating from the circular shape and no other growths around it.