and respiration occur in lake
settings. In this lesson you use microcosms and RUSS data to investigate
changes in oxygen concentrations that result from photosynthesis and
As a biology
student your teacher has challenged you to demonstrate that photosynthesis
and respiration occur in lakes.
I - Microcosm Set-up
Read the "Introduction to Cell Respiration and
Photosynthesis" before beginning the exercises.
knowledge of photosynthesis and respiration. How do these processes
affect water quality measures in lakes? Which measures should be analyzed
as indicators of photosynthesis and respiration.
you use lab microcosms to demonstrate that photosynthesis and respiration
occur in water samples in a lab setting? You have the following materials
available for your use.
- 3 - 8 oz or 250 ml jars
- 10 - 8 cm sprigs of Elodea sp.
- 8 - 5 cm fathead minnows
- oxygen, carbon dioxide, and
pH kits (meters may be substituted)
- a sunny window or a grow light
to choose a water quality measure(s) to analyze in your microcosms.
Research the effects that respiration can have on water temperature,
and DO using
the "Understanding" portion
of the WOW web site. Choose a measure that correlates strongly to photosynthesis
and aquatic respiration.
procedural plan for testing your hypothesis. The plan should include
enough detail that other students could follow it without consulting
with you. Include your predictions for the results of your tests.
results. Be sure to carefully follow the directions for using the kits
Management and Analysis
data and summarize your results. Title your graphs and label legends,
axes, and units of measure.
on some possible explanations for your experimental results. Do the
results indicate photosynthesis and/or respiration? Compare results
with different student groups. What might account for similarities
or differences among results?
a presentation of your results using the format specified by the teacher:
written paper, oral presentation, poster, or multi-media presentation.
The final presentation reflects both parts of the lesson.
II - Using WOW Technologies
in the discussion of lab microcosm results. How might photosynthesis
and aquatic respiration affect water chemistry in a lake environment?
procedural plan for using WOW data to demonstrate that photosynthesis
and respiration occur in a lake. Be sure your plan includes directions
on the date(s) and depths to use for data collection.
how the laboratory variable(s) you studied will change in a lake environment.
Do you expect a different response? Why?
how you will organize and record the data you collect. Using the "Data" portion
of the WOW website, collect all of the data you need.
Management and Analysis
the data. Analyze the data for changes in the laboratory variable(s)
you studied. Also look for other changes that might correlate to photosynthesis
or respiration. Is there a pattern in the data?
graph of your data. Be sure to label axes and include a title and legend.
the results of your microcosm set-up and RUSS data investigation. Compare
your results with the equations for photosynthesis and respiration.
What are the relationships among data? What does the lab microcosm
and lake study show?
a presentation explaining the effect of photosynthesis and respiration
on aquatic chemistry. The presentation can be a written paper, oral
presentation, poster, or multi-media presentation. Include your graphs
and summaries in the presentation.