Study photosynthesis and primary productivity
- A Great Solution for AP Biology* Lab 12
- Expose algae solutions or pond water to varying amounts of light
- Use a dissolved oxygen sensor to measure the efffect of light intensity on photosynthetic activity
The Teaching Challenge
The quality of an aquatic environment is largely based on the level of dissolved oxygen (DO) available to organisms as it is necessary for metabolic processes. In AP Biology Lab 12: Dissolved Oxygen and Primary Productivity students are asked to incubate algae solutions that are exposed to varying amounts of light and then take a DO measurement in order to calculate the primary productivity of the algae, a measure of the photosynthetic activity of an aquatic ecosystem.
Traditionally this means students using small glass bottles that are wrapped in black plastic screens held in place with rubber bands and tape, using additional screens (up to 8) to block more light. The problem is that the exact amount of light being transmitted can’t really be quantitatively measured which leads to inaccurate results. Furthermore, complications in affixing the screens may lead to overlap (reducing light more than desired) or gaps that let light directly in affecting results. Finally, the technique used to take DO measurements (the Winkler method) requires many steps and several chemicals making it time consuming and open to errors at each step.
Key Benefits
- A low cost, easy to use, enhancement of two required AP Biology Labs
- A solution for ANY experiment in which the effects of light on photosynthesis are being tested.
- Easy enough for elementary school students to use, but sophisticated enough to be used in AP Biology Labs.
The PASCO Solution
Remove any ambiguity and get exact results. The Aquatic Productivity Bottles eliminate potential errors by limiting the light entering the bottles in a precise way. Five identical transparent bottles are placed in a rack. The custom design of the rack shields the bottles, blocking a fixed percentage of light in 25% increments from zero to 100%.
Students fill the bottles with algae solution or pond water and then measure the dissolved oxygen concentration in the solutions before and after incubation in florescent light. By comparing the dissolved oxygen concentrations in each solution, students learn about the relationship between light intensity, dissolved oxygen concentration, photosynthetic activity, and the primary productivity of aquatic ecosystems.
And by using the Dissolved Oxygen Sensor to take the measurements, the activity can be done much more effectively and quickly leaving more time to discuss and analyze the results.
Solution at a Glance
| Qty. | ||
| Aquatic Productivity Bottles (ME-6937) | $29 | 1 |
| PASPORT Dissolved Oxygen Sensor (PS-2108) | $225 | 1 |
| SPARK Science Learning System (PS-2008A) | $349 | 1 |
For more product information and to order products separately, see below.
How It Works
Fill the Aquatic Productivity Bottles with algae solution or pond water, ensuring that there are no air bubbles in the bottle. Measure the initial dissolved oxygen (DO) concentrations of the solutions with a Dissolved Oxygen Sensor. Place the bottle into the rack and lock the specially molded, light-varying lid into place over the bottles. Incubate for 24 hours in fluorescent light. After 24 hours, remove the bottles from the rack and measure the DO concentration again. Use the initial and final DO concentrations, students can calculate Net Primary Productivity and Gross Primary Productivity of the aquatic ecosystem.
Clearly demonstrate the relationship between light intensity and Net Primary Productivity (and Gross Primary Productivity) using measurements of dissolved oxygen concentrations.
Here's What You Need
U.S. Educator prices shown.
What you need
Aquatic Productivity Bottles (ME-6937) - $29
This rack filters 0%, 25%, 50%, 75% and 100% of incident light to simplify the study of primary productivity. Includes set of 5 transparent plastic bottles.
PASPORT Dissolved Oxygen Sensor (PS-2108) - $225
Provides real-time, aqueous oxygen concentration measurements. For use with PASPORT Interfaces.
Includes:
- Electrode with 10 foot (3 m) cable
- Replacement membrane
- Membrane removal and installation tool
- Replacement silicone O-ring
- Bottle (60 mL) of electrolyte probe filling solution
- Syringe
PASPORT Water Quality Sensor (PS-2169) - $379
Measures temperature, conductivity, pH/ISE/ORP and dissolved oxygen. It is specifically designed for convenience in conducting water quality lab experiments. For use with PASPORT Interfaces.
Includes:
- Stainless Steel Temperature Probe
- pH Probe
- Dissolved Oxygen Probe
- Conductivity Probe
SPARK Science Learning System (PS-2008A) - $349
An all-in-one mobile device that seamlessly integrates the power of probeware with inquiry-based content.
Includes:
- SPARK handheld
- Fast response temperature sensor
- Voltage sensor
- Power adapter
Advanced Biology Teacher Guide (PS-2876B) - $129
This manual features over 25 challenging, standards-based lab activities including all 12 required AP Biology labs.
Includes:
- Advanced labs including the required labs for AP® Biology.
- Editable Word files for each student version
- CD containing all information in electronic format
Additional Information
Also required - light source, algae or pond water.
*"AP Biology is a registered trademark of the College Board, which was not involved in the production of, and does not endorse, this product."
