|
Names: _________________________________________
Date: _________________________
Part 1 - pH in a Microcosm
Data Collection
After setting up the microcoms,
enter your predictions in the tables below. Then record the initial
values
for each parameter.
After the microcosms have sat for 20-30
minutes, you can record your results. In determining the final values,
begin by collecting and testing water samples for oxygen. Then record
the pH and CO2 values.
Aged Water Only
|
Microcosm
A
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Buffered Water
|
Microcosm
B
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Minnows Only
|
Microcosm
C
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Minnows in Buffered Water
|
Microcosm
D
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Pondweed Only
|
Microcosm
E
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Pondweed in Buffered Water
|
Microcosm
F
|
Prediction
|
Initial
Value
|
Final
Value
|
|
DO
(mg/l)
|
|
|
|
|
pH
|
|
|
|
|
CO2
(mg/l)
|
|
|
|
Data Management and Analysis
Write the equations
for photosynthesis and respiration. Were the changes that you observed
in oxygen and
carbon dioxide
concentrations consistent with the equations? Explain.
Write the carbon-dioxide bicarbonate equilibrium
equation. Which microcosms showed changes in pH? Were the changes consistent
with this equation? Explain.
Part 2 - Effects
of pH in Lakes
Data Collection
Fill in the following tables
with the WOW data collected by the RUSS. Construct graphs that show
the lake's
pH profiles for each date. Do not collected the DO data until you have
made a hypothesis about the lake's oxygen profile based on your
pH information.
Summer pH and DO for Ice Lake
Date: _______________
|
Depth
(m)
|
pH
|
Predicted
DO
|
Actual
DO
|
|
2
|
|
|
|
|
4
|
|
|
|
|
6
|
|
|
|
|
8
|
|
|
|
|
10
|
|
|
|
|
12
|
|
|
|
Winter pH and DO for Ice Lake
|
Depth
(m)
|
pH
|
Predicted
DO
|
Actual
DO
|
|
2
|
|
|
|
|
4
|
|
|
|
|
6
|
|
|
|
|
8
|
|
|
|
|
10
|
|
|
|
|
12
|
|
|
|
Interpretation of Results
Based on the results from the microcosms,
do you think Ice Lake was stratified or mixed in the winter? In the
summer?
Do you think Ice Lake was depleted of
oxygen at any depth in the winter? In the summer?
How would you explain your results?
|
Studying
the Effect of
pH on Aquatic Organisms
back
to the basic science studying index
