Aquatic respiration can have a profound effect on an ecosystem. In the laboratory
portion of this lesson, you explore how aquatic respiration affects
water chemistry. Dissolved oxygen
(DO) and pH are used as the
indicators of the complex chemical interactions which occur. In the
second part of the lesson, you use RUSS data to explore the changes
in pH and DO that occur in the hypolimnion
during the summer.
I Aquatic Respiration in a Lab
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 of time.
what happens. Why do the animals often die in these situations? What
water quality measures might relate to this situation? Why might similar
situations occur in lakes?
the following equipment:
- Hach or Lamotte water quality testing materials (for analyzing dissolved oxygen
and pH.) You will perform up to 5 analyses for pH and for DO if using
meters, or two analyses if using chemical reagent kits.
- 250 ml bottle with a cap
- One (or more) of the following three options to place in your bottle:
- 4 two-inch minnows (fathead minnows are readily available and
tolerant of low oxygen levels)
- 75-100 ml of sandy sediment
- 75-100 ml of organic/mucky sediment
- A copy of the Respiration in a Microcosm Worksheet
contains additional experimental design considerations and instructions
for microcosm set-up.
the worksheet for these lesson components.
II Aquatic Respiration in a Lake
how what you have learned from working with microcosms might apply
to a lake environment. How would you interpret changes in pH and DO
the hypolimnion of a lake?
a copy of the Aquatic Respiration in a Lake
worksheet and access to WOW water quality data from a lake.
Design, Data Collection, Data Management and Analysis, Interpretation
of Results, and Reporting Results
the Aquatic Respiration in a Lake worksheet for these lesson components.