Dissolved Oxygen and Primary Productivty Lab
AP Biology
Dissolved Oxygen and Aquatic Primary Productivity
Purpose: To measure and analyze the primary productivity of natural waters of laboratory cultures using screens to simulate the decrease of light with increasing depth.
Background: Dissolved oxygen (DO) is how oxygen is measured. Oxygen is required in cellular respiration, so it is very important for aquatic life. When more oxygen is consumed than is produced, dissolved oxygen levels decline and some animals could die if they do not move to waters with higher oxygen levels. DO can be expressed as parts per million or mg/L. DO levels change frequently throughout the day and seasonally because of water temperature, pH, and other variables. Dissolved oxygen is oxygen that has dissolved in water through diffusion from the surrounding air, as a waste product of photosynthesis, or aeration of water that has tumbled over falls and currents; the oxygen mixes in with the water during the rapid motion.
Primary productivity is the rate at which autotrophs store organic materials. Included in primary productivity is gross and net productivity. Gross productivity is the entire photosynthetic production of organic compounds in an ecosystem. Net productivity is the gross productivity minus the amount of organic compounds given off during cellular respiration. Dissolved oxygen can be used to measure the primary productivity of an aquatic ecosystem. The amount of productivity depends on the amount of light the body of water receives.
Question/ Problem: How will the production of a pond inhabited by the photosynthetic protest Chlorella vary when exposed to different light intensities?
Hypothesis: If pond samples are exposed to different light intensities, then the net and gross production will be the highest at the sample with the most light exposure because the Chlorella will produce more oxygen.
Materials:
7 BOD bottles
Chlorella culture
Gloves
Manganous sulfate
Starch indicator
Sulfamic acid
Dissolved Oxygen and Aquatic Primary Productivity
Purpose: To measure and analyze the primary productivity of natural waters of laboratory cultures using screens to simulate the decrease of light with increasing depth.
Background: Dissolved oxygen (DO) is how oxygen is measured. Oxygen is required in cellular respiration, so it is very important for aquatic life. When more oxygen is consumed than is produced, dissolved oxygen levels decline and some animals could die if they do not move to waters with higher oxygen levels. DO can be expressed as parts per million or mg/L. DO levels change frequently throughout the day and seasonally because of water temperature, pH, and other variables. Dissolved oxygen is oxygen that has dissolved in water through diffusion from the surrounding air, as a waste product of photosynthesis, or aeration of water that has tumbled over falls and currents; the oxygen mixes in with the water during the rapid motion.
Primary productivity is the rate at which autotrophs store organic materials. Included in primary productivity is gross and net productivity. Gross productivity is the entire photosynthetic production of organic compounds in an ecosystem. Net productivity is the gross productivity minus the amount of organic compounds given off during cellular respiration. Dissolved oxygen can be used to measure the primary productivity of an aquatic ecosystem. The amount of productivity depends on the amount of light the body of water receives.
Question/ Problem: How will the production of a pond inhabited by the photosynthetic protest Chlorella vary when exposed to different light intensities?
Hypothesis: If pond samples are exposed to different light intensities, then the net and gross production will be the highest at the sample with the most light exposure because the Chlorella will produce more oxygen.
Materials:
7 BOD bottles
Chlorella culture
Gloves
Manganous sulfate
Starch indicator
Sulfamic acid
Cited: http://www.phschool.com/science/biology_place/labbench/lab12/primary.html http://water.epa.gov/type/rsl/monitoring/vms52.cfm http://www.lenntech.com/why_the_oxygen_dissolved_is_important.htm