Beneath the Boxwood Bush

In the early afternoon of February 10, we began the process of searching for microbes hidden in the ground, found in soil around the campus of Birmingham-Southern College. During the next several weeks, we will be performing experiments and recording observations on our soil sample to determine the microbes found in the soil. We collected our soil directly beneath a boxwood bush and nearby several holly bushes. The temperature on 02/10/15 had a low of 30° F and a high of 48° F, while the temperature was 46° F when our sample was collected. The ground was cold, in comparison to an average day of warmer temperatures and found in a shaded area under the boxwood bush. The soil was rocky and abnormally dry, with rainfall accumulating only 0.06 inches over the past nine days. Air humidity was also low in comparison to humidity levels during warmer days. Below are photographs of the geographical nature and habitat of the location where soil was collected. 15 mL of soil was removed from the ground, but the habitat was left unharmed. 0.5 g of soil was mixed into 50 mL of sterile water, and then diluted to form solutions 10^-3, 10^-4, 10^-5, 10^-6, 10^-7. These solutions were transferred to appropriately labeled Petri dishes containing tryptic soy agar, with an additional plate of Rose-Bengal agar with the 10^-4 dilution. The Petri dishes were left to incubate at room temperature for seven days. We will be updating this post about the progress of microbial growth on the Petri dishes on day 7.

On day 7, our preliminary results showed various growth patterns on each of the six Petri dishes, shown below. The diluted solution 10-3 had the largest microbial growth showing multiple circular, large colonies that were milky white. The 10-4 solution had less colonies but had an abnormally large colony with few smaller colonies surrounding it. Diluted solutions for 10-5 and 10-7 showed less and less microbial growth, with only one or two colonies present. However, the diluted solution at 10-6 had a larger, red colony on the edge of the plate and was the only solution that had microbial growth of a different color than milky white. The solution on the Rose- Bengal agar with 10-4 dilution had one large, circular, milky white colony present.

- Heather Daniel