September 10

Collecting Soil Metadata and Washing 9/10/18

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Rationale: Today we are collecting metadata on the soil samples we collected last week in order to have data to minimize confounding variables in our findings, therefore increasing our reproducibility.

Procedure: Collecting Metadata:

  1. First, I prepared the percent water analysis. I weighed a petri dish by itself which was 7.57g. I then added some soil I collected from tree B, described in 9/5/18 notebook. The mass of the dish and soil was 12.51g.
  2. I placed the dish under the vent hood to let dry over the next 48 hours.
  3. Next, I prepared the soil, silt, clay analysis. I poured 10mL of the tree B soil

    into a falcon tube. I then filled it with DI water to the 30mL mark.

  4. I then added 3 drops of soil dispersion fluid then dropped my tube on the

    floor causing all the contents to spill.

  5. After taking proper precautions and cleaning up my area and cleaning out

    my falcon tube I repeated the last two steps.

  6. I shook the tube vigorously for a little less than a minute then I waited for a

    minute and placed it in a test tube rack to sit for 48 hours.

  7. Before starting my pH test I started my soil washing described below.
  8. I took a pH test vial and cap and added an extremely small amount of soil

    sample then filled the rest of the vial with water.

  9. I placed the cap on top and shook back and forth for about a minute then let

    sit until the soil settled.

10.I placed an inch-long piece of pH paper in the vial then analyzed the color

against the chart to find the pH.
11.I repeated the process to make sure my findings were correct and got the

same result. Soil Washing:

  1. Stored about 2mL of soil from tree B in a 15mL tube then filled with LB broth up to 12mL.
  2. Shook using a vortexer for about 14.5 minutes.
  3. Added 5 drops of DI water to get the right mass to match my partner within

    .1 grams.

  4. After spinning down my tube I filtered my supernatant using a 22μL filter

    and a vacuum to a 50mL tube.

5. I added 0.5mL of arthrobacter to the tube and placed the tube in a shaking incubator after labeling it “enriched”.

Observations:
The results of the soil, silt, and clay analysis were: 19.05% Clay, 2.381% Sand, and 78.57% Silt. The pH of the soil was about 8.0 or 8.5. Lastly, the weight after the 48 hours of drying was 12.21 grams. 4.94 grams of soil with moisture and 4.64 grams after drying therefore, a 6.47% moisture in the soil sample recorded.

Interpretation and Next Steps:
The soil was unusually basic and had a very low amount of moisture. This could either be a cause of the death of the tree or a result of the death of the tree. It is a good idea to keep this data in mind when I analyze my data further down the road, but for now I should proceed in performing a spot test and a plaque assay to search for the presence of phage in this soil.


Posted September 10, 2018 by sriram_avirneni1 in category Sriram Avirneni

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