The question has the students graph percent saturation as a function of temperature. There are several factors that effect the dissolved oxygen levels in aquatic environments.
Each bottle is set up so that air is drawn through the enclosure and passes over carbon dioxide-absorbent material. Distance from a light source alone involves too many variables; age of the bulb, reflector efficiency, etc.
The method used to determine the amount of dissolved oxygen in the water is the Winkler titrametric method. She thinks that the new spring water jugs have UV protectant in the plastic. The energy remaining after respiration and stored as organic matter is the net primary production, or growth.
I like to use specific amounts of duckweed in the DO bottles so you can get better control of the amount of producer biomass. The data in this lab have seemed pretty erratic to me over the years that I have done it, but the new manual is certainly an improvement over the old procedure.
Monitor temperature degrees Celsius optimum. The Trophic State is the amount of nutrients in the water. A scoop of sulfuric acid was added, and the bottle was inverted until all of the precipitate dissolved.
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It may take days to achieve the density you need in the 4-liter flask. This is the end of the third year on these cultures and I may start fresh as they are not looking as nice and green as last year You probably have mucho bacteria and very little phytoplankton.
If you will need the culture early in the week, you may grow the algae for three days the week before the experiment, then remove it from continuous lighting put it in a window over the weekend and use it the following week.
Measurement of Primary Productivity Part B required a sample bottle of water from a natural source, 7 BOD bottles, aluminum foil, 17 cloth screens, rubber bands, a light, thermometer, concavity slides, light microscope, mangonous sulfate, alkaline iodide, thiosulfate, a 2-mL pipette, sulfuric acid, a mL sample cup, a white piece of paper, starch solution, and a nomograph.
So, I have three recommendations: Productivity Simulation This section required pencil, paper, calculator, and graph paper.
They will grow all summer and be nice and dark green by fall and I will do that lab early in the fall. I have also used slow-moving streams. I see the purpose of this graph to show the inverse relationship between temperature and dissolved gases. It was left at room temperature until the other samples were processed.
One drop of the titrant was added at a time until the color changed to a pale yellow color. Measurement of Dissolved Oxygen Table 1.Dissolved Oxygen and Primary Aquatic Productivity Laboratory 12 Introduction Dissolved oxygen levels are an extremely important factor in determining the quality of an aquatic environment.
Dissolved oxygen is necessary for the metabolic processes of almost every organism.
Terrestrial environments hold over 95% more oxygen than aquatic. So the gross productivity (the full photosynthetic production in this ecosystem) of the algae in the bottle is the 5mg dissolved oxygen lost to respiration added back to the 10 mg dissolved oxygen accumulated in the bottle kept in the light.
a. How does putting a sample of pond water and algae/freshwater plants in the light enable us to measure gross productivity? It helps us measure oxygen. LabBench Activity Dissolved Oxygen and Aquatic Primary Productivity.
by Theresa Knapp Holtzclaw. Introduction. In an aquatic environment, oxygen must be dissolved in order to be available for use by organisms.
In this investigation, you will measure and analyze the dissolved oxygen (DO) concentration in water samples at varying temperatures. You will also measure and analyze the primary productivity of natural waters or laboratory cultures using screens to simulate the attenuation (decrease) of light with increasing depth.
Active Page: Lab Dissolved Oxygen and Primary Productivity Dissolved Oxygen and Primary Productivity "The volume of oxygen dissolved in water is dependent on: temperature; partial pressure of oxygen in the atmosphere; concentration of dissolved salts; biological activity.Download