Team+5

Team 5: Sarah, Tyler, Michael, Trey

Should be named Team Awesome.


 * Title**: Testing for the net productivity using dissolved oxygen levels in bottles at various simulated depths


 * Purpose**: The primary objectives of this lab are to measure dissolved oxygen in a water sample using the Winkler Method, measure primary productivity, and to investigate some factors that can affect the primary productivity of a system.


 * Hypothesis (part a)**: If temperature has an affect on the amount of dissolved oxygen in a substance, then water at a lower temperature will have a higher amount of dissolved oxygen than will water at a higher temperature.


 * Hypothesis(part b)**: If light has an effect on the productivity of algae, then a bottle in 100% light will have more dissolved oxygen than will bottles of increasing darkness.


 * Materials**:
 * BOD bottles
 * //Chlorella// culture
 * Manganous sulfate
 * Sulfamic acid
 * Sodium thiosulfate
 * Measuring spoon
 * Alkaline potassium iodide azide
 * Titration syringe
 * Starch indicator
 * 20mL sampling vial
 * Graduated cylinder
 * Fiberglass screens
 * Tape
 * Aluminum foil


 * Procedure**: Please refer to pages S-2, S-3, and S-6 of the packet for details.


 * Data and Observations**:
 * Bottle || DO || Net Productivity || Gross Productivity ||
 * Baseline (initial) || 10 ppm || 0 ppm || 10 ppm ||
 * Dark || 0 ppm || -10 ppm || 0 ppm ||
 * Light (0 screens) || 20 ppm || 10 ppm || 20 ppm ||
 * 1 screen || 8.9 ppm || -1.1 ppm || 8.9 ppm ||
 * 3 screens || 0 ppm || -10 ppm || 0 ppm ||
 * 5 screens || 0 ppm || -10 ppm || 0 ppm ||
 * 8 screens || 0 ppm || -10 ppm || 0 ppm ||
 * Temperature (F) || Group DO ||  ||   ||
 * 10 degrees || 10 ppm ||  ||   ||
 * 20 degrees || 9 ppm ||  ||   ||
 * 30 degrees || 8 ppm ||  ||   ||
 * 30 degrees || 8 ppm ||  ||   ||




 * Analysis**:Covering the algae with screens significantly impacts the rate of productivity. Based on the data above, the algae can only have a positive gross productivity if there is only one screen covering the water maximum.

Also, there seems to be a steady trend between the temperature of the water and the dissolved oxygen measurements. Each time the temperature increased by ten degrees, the amount of dissolved oxygen decreased by 1 ppm. Based on this, it is logical to infer that at 40 degrees, the amount of dissolved oxygen will be at 7 ppm.


 * Conclusion A**: Based on the results, our hypothesis that lower temperature will have higher dissolved oxygen is accepted because at 10 degrees, the water had 10 ppm, whereas at 20 degrees it had 9 ppm, and at 30 degrees it had 8 ppm.


 * Conclusion B**: Based on the results, our hypothesis that the bottle of algae with more light will have higher dissolved oxygen is accepted because the bottle with 0 screens gained 20 ppm of dissolved oxygen, and the bottle of algae with 1 screen lost 1.1 ppm of dissolved oxygen. Bottles of algae with 3, 5, 8 screens, and the bottle of algae in the dark lost 10 ppm of dissolved oxygen.