Andrew is an undergraduate researcher. He has hypothesized that the sediment on the bottom of University Lake at LSU contains more fecal coliforms (e.g., E. coli and others) than the sediment on the bottom of Lake Pontchartrain in Covington, LA or the sediment on the bottom of the Lake Martin near Lafayette, LA. He makes selective and differential agar that is specific for fecal coliforms. He inoculates the surface of the agar in a Petri dish for each of these 3 samples. He places 1 gram of sediment on the Lake Pontchartrain plate, 750 milligrams of sediment onto the University Lake plate, and 6.25 g of sediment onto the Lake Martin plate. He incubates the plates at 37 degrees Celsius, which is body temperature for humans. The next day he counts the fecal coliforms as CFU (colony-forming units). He finds there are 7 CFU on the Lake Pontchartrain plate, 51 CFU on the University Lake plate, and 25 CFU on the Lake Martin plate. Do the calculations and mark the statements that are true. Check all that apply and only those that apply.
a. Andrew used more sediment to inoculate the Lake Martin plate than he used to inoculate the Lake Pontchartrain plate.
b. All 3 plates were inoculated with the same amount of sediment.
c. Pound for pound (or gram for gram), the University Lake sediment was the dirtiest in that it contained the highest density of fecal coliforms.
d. Andrew was right.
e. The Lake Martin sample contained 4 CFU/g of fecal coliform bacteria.
f. Andrew was wrong.
g. The Lake Pontchartrain sample contained 0.14 CFU/g of fecal coliform bacteria.
h. The University Lake sample contained contained 51 CFU/g of fecal coliform bacteria.
i. After incubating the plates, the University Lake plate had approximately twice as many CFU's as the Lake the Martin plate, but the bacterial density (CFU/g) was 17 times higher.