29 October 2018 ✷ Soil 6 “redo”

Rationale: Soil sample 6, a sample taken from near the bear habitat, was enriched and incubated, but one well turned green with contamination. The samples from the other wells were not visibly contaminated, but all were filtered in order to be spot tested for phage.

Procedure

• The lab table was cleaned with Cidecon and 70% ethanol.
• 
• A pipette was used to remove approximately 1 mL of the first and 1 mL of the third row fluids; each into its own microcentrifuge tube where it was centrifuged at 13300 g for 2 minutes.
• the top layer of fluid was then removed with a syringe and filtered through a syringe filter (22 micron). The samples were then stored overnight in a refrigerator.

Data, results, observations

Percent Sand: 75%

Percent Silt: 12.5%

Percent Clay: 12.5%

percent water: 83.67%

Interpretations, Conclusion, Next Steps

The arthrobacter in the sample that turned green was likely outcompeted by a bacterium such as pseudomonas. None of the other wells were noticeably contaminated, but all samples will be spotted in the following lab period to see what takes place and if a phage is present regardless of the contaminant.