How does increasing alkalinity affect common soil bacteria?
A. Collect soil samples to inoculate plates Samples can be collected from a variety of sources. Soil and mud from ponds, roadside ditches, flowerpots, and gardens are rich sources of microbes. Sand is not as microbially rich and does not easily form a slurry, which makes colony formation take longer. You can also collect bacterially-rich water from standing water and birdbaths. Inoculate plates directly with this water. It might be interesting to collect samples from sites of different pH and observe growth patterns. For example, slag heaps are generally alkaline and swamps are generally acidic. To collect an environmental sample: • Collect about 1 gram of soil/sediment from the environmental site in a tube (e.g., a capped test tube, disposable centrifuge tube, or culture tube). • Add 10-15 ml of water from the same site, if possible. (If none is available, use sterile water). • Shake to create a slurry. B. Make tryptic soy agar* plates (the listed amounts make 40-50 plates, adjust as
