Science Buddies: "Ask an Expert"

Hi-

I am in the beginning stage of conducting my experiment for science. I plan to test different conditions of water (one with little nutrients, one with too much nutrients, and one that is equilibrium or normal) to see how it affects how much oil the Alcanivorax borkumensis bacterium digests.
My independent variable is: changes in the different conditions of water
My dependent variable is: amount of oil consumed

My questions/concerns are:
1) What type of water should I use?
*Note: I am not testing this in the ocean. I am creating a mock experiment.
2) How much nitrogen and phosphate should I use?
3) What are the normal amounts of nitrogen and oxygen in the water? How can I convert that in terms of my experiment?
4) What type of oil should I use and how much?
5) How do I calculate how much oil the bacterium has digested?

Thanks!

P.S: I am making a scale model of the experiment at home.