respiration can have a profound effect on an ecosystem. In this
lesson you explore how aquatic respiration affects water chemistry in
a laboratory setting. You need to determine which water quality measures
to use as indicators of the complex chemical interactions that occur.
Then, in the second part of the lesson, you use WOW data to explore
the changes in your selected water quality measures that occur in the
hypolimnion of a lake during the summer.
I - Aquatic Respiration in a Microcosm
in the class discussion of events such as aquaria that have been overfed
or left untended for prolonged periods of time, or minnow buckets that
have been left without fresh water for a prolonged period. Consider
what happens. Why do the animals often die in these situations? What
water quality measures might relate to the situation? Why might similar
situations occur in lakes?
A lake association
curious about the effects of aquatic respiration on its lake has hired
you as a consulting biologist. The lake association has asked you to
answer the following questions:
- Can you
demonstrate how respiration occurs in aquatic organisms?
- Can aquatic
respiration be quantified?
- How does
aquatic respiration affect water chemistry?
the effects that respiration can have on pH,
(see the RUSS Unit section for more
in-depth explanations). Use the WOW page and links. You need to determine
which water quality measures to use as indicators of the chemical interactions
that occur. The following equipment is available for your use:
- Water quality
testing kits or meters
- 250 ml bottles
- 2-inch minnows
- samples of
- samples of
pens or CO2 testing kits
to plan and execute an experiment that can be completed in about one
hour (one class period) in a laboratory setting to answer the lake association
questions. Write out the procedures for your experiment before you begin.
Your procedural plan should have enough detail so that someone else
could complete the experiment without consulting with you.
quality measures should be used as indicators? What are your predicted
results from the experiment?
how you will collect the data you need from your experiment. (Your data
collection should include a table for recording data.) Write your description
as a protocol (step-by-step directions) that others could follow. Create
a table for recording the data from your experiment.
Management and Analysis
the results of your experiment. Include a graph to show your results.
possible explanations for your experimental results.
to make a presentation to the lake association to provide your answers
to their questions. Your teacher will specify the format: a written
paper, an oral presentation, a poster, or multi-media presentation.
Your presentation should include the information you considered during
Part I of the lesson and the data collected and analyzed in Part II.
Conclude your presentation with the next steps the lake association
should take to more fully understand aquatic respiration.
II - Aquatic Respiration in a Lake
may change in response to biological activity. In this part of the lesson
you investigate how water chemistry changes as a result of respiration.
how what you have learned from working with microcosms might apply
to a lake environment.
association is now concerned about water quality in
of its lake during the summer and has hired you again as a consulting
biologist. It wants answers to the following questions:
- How does
aquatic respiration affect water quality during the summer in the
hypolimnion of the lake?
causes the changes in water quality measures?
to research your selected water quality measure in the hyplimnion using
RUSS data. Consider how respiration drives changes in your measure.
What type of changes will reflect respiration? Will the changes show
daily or seasonal variation? Why?
the WOW lake you will investigate. Again, be sure to write out the procedures
for your research before you begin.
table to organize the data you collected from your lake. Download data
for your selected parameter. Consider how to deal with data that you
suspect is incorrect due to sampling or technological errors.
Management and Analysis
graph that illustrates the changes in the water quality measure you
your data, write a summary of the changes in your identified parameters
in the lake's hypolimnion during the summer.
will specify a format for presenting your results to the lake association:
a written paper, an oral presentation, a poster, or multi-media presentation.
Your presentation should reflect data collected and analyzed in both
parts of the lesson. Conclude your presentation with the next steps
the lake association should take to more fully understand the dynamics
of water quality in their lake.