Lab #11

11/2/17

Purpose: The purpose of this lab activity is to determine the soil ciliate biodiversity within the soil samples collected earlier in the semester. Techniques such as determining soil water content, preparing a non-flooded plate, finding soil pH, will help us discover ciliate abundance and diversity.

Procedure

Determining % Soil Water Content

• Remove soil samples from drawers
• Weigh the samples and calculate the mass of the water that has evaporated from the soil
• Convert this to a percent
  • Wet soil – dry soil / wet soil x 100 = %water
• Add information to the Soil Data Sheet

Soil pH Protocol

• Place about 3 mL of soil in a labeled 10 mL Falcon tube and fill to the 8mL mark with DI water. Mix for 3-5 minutes and let soil settle to the bottom.
• Remove about 1 mL of liquid from the top of the tube and transfer it to a microfuge tube.
• Spin the tube in the centrifuge for 1 minute to pellet the soil.
• In order to test the pH of the soil, remove a small strip of pH paper and place it in a clean glass tube. Add the clear soil water so that you submerge the strip.
• Wait 1 minute and record the result after comparing the color. If your result is on either end of the scale, you can use another range of paper to test below 5 or above 9.
• Record the pH in your notebook.

Determining Soil Texture

• Remove the sticks and leaves from the soil sample
• Add soil to about the 4mL mark in a Falcon tube
• Add water and mix vigorously
• Add 1 drop of dispersing agent and remix
• Observe the tube after 30 seconds. The sedimentation of sand particles will have occurred
• Let the tube sit undisturbed overnight or until the next lab.
• Use a ruler to measure the %sand, silt, and clay. This procedure works best by taking a clear picture of the tube and zooming in on the sedimentation lines
• Determine the % of each type of soil particle
• Record your findings in your notebook.

Non-Flooded Plate

• Put 10-50g of air dried soil in a petri dish with enough to cover the bottom of the plate on one side.
• Saturate but don’t flood the sample with DI water. Add water until about 5mL of water will drain off when the petri dish is tilted.
• Observe the soil using a dissecting microscope.
• Use the micropipette to remove 100 microliters of liquid sample. Transfer this to a concavity slide to observe and further isolate. Record the number of ciliates observed.
• Isolation may be done by serial dilution if there is more than one type of ciliate in the sample.
• Once you have captured a ciliate, transfer it to 500 microliters of media in a clean 24 well plate.
• Keep the lid on the non-flooded plate to decrease evaporation but still allow airflow and gas exchange.
• Continue to check on the plates.

Data & Observations

Soil Water Content

Initial Mass: 23.4 g

Final Mass: 22.1

Mass of Petri Dish: 11.3 g

Soil Water Content: 10.74% water

pH of Soil: 6.5

Non-Flooded Plate Observations after 24 hours

• No ciliates were found under the dissecting microscope. The ciliates may still be in the insisted/ hibernating state because of drying phase of soil preparation.

Conclusion: This lab was meant to prepare our soil for examination for ciliates. I am very excited to see where this lab will take us because the possibility of finding a new type of ciliate is very encouraging. The next steps in this lab is to continue to make observations on the non-flooded plate and tube. My work was labeled AJR34F17 and stored until the next lab.