102
Exercise 7
silicone rubber. Practically none of the electrodes is completely specific, and all are
subject to interference by other ions.
EXERCISES
OPTION 1. FIELD TRIPS
1. From the central depression of a lake or at several stations in, above, and below tributary
inlets to a stream, collect water samples for chemical analyses with a scrubbed Van Dorn or
similar water sampler. Dispense with minimal agitation and aeration into clean, amber
polyethylene bottles. Fill the bottles to the brim and cap tightly. Store samples in an ice chest
for transport to the laboratory. Collect replicates at each depth.
2. Determine the temperature of the water at each depth throughout the vertical profile with an
underwater thermometer (see Exercise 2).
3. Collect water samples for analyses of concentrations of dissolved oxygen throughout the
water column using the procedures in Exercise 6.
4. Collect water samples for chemical analyses from (a) inlet sources and (b) the outlet of a lake,
and in the littoral zone among dense stands of aquatic macrophytes. Compare values
obtained from these sources with those from comparable depth in the center of the lake (open
water).
5. Return to the laboratory as promptly as possible and perform the chemical analyses as
discussed above for:
a. Ammonium nitrogen.
b. Nitrate and nitrite nitrogen.
c. Soluble reactive phosphorus.
d. Total phosphorus (particulate and dissolved fractions).
e. Dissolved silica.
f. Major ions, if equipment is available.
g. Specific conductance.
h. Total "dissolved" residues.
Depending on the amount of time available for such analyses, the content of these exercises may
require two or more class periods. Once you are familiar with the methods, the work load can be
divided easily among teams to perform all of the analyses simultaneously.
OPTION 2. LABORATORY EXERCISES
1. From the water samples provided by your instructor, perform the chemical analyses as
discussed earlier in this exercise for:
a. Ammonium nitrogen.
b. Nitrate and nitrite nitrogen.
c. Soluble reactive phosphate.
d. Total phosphorus (particulate and dissolved fractions).
e. Dissolved silica.
f. Major ions, if equipment is available.
g. Specific conductance.
h. Total "dissolved" residues.
Work in teams to perform the analyses simultaneously, then rotate to learn the techniques of
all analyses.
Exercise 7
silicone rubber. Practically none of the electrodes is completely specific, and all are
subject to interference by other ions.
EXERCISES
OPTION 1. FIELD TRIPS
1. From the central depression of a lake or at several stations in, above, and below tributary
inlets to a stream, collect water samples for chemical analyses with a scrubbed Van Dorn or
similar water sampler. Dispense with minimal agitation and aeration into clean, amber
polyethylene bottles. Fill the bottles to the brim and cap tightly. Store samples in an ice chest
for transport to the laboratory. Collect replicates at each depth.
2. Determine the temperature of the water at each depth throughout the vertical profile with an
underwater thermometer (see Exercise 2).
3. Collect water samples for analyses of concentrations of dissolved oxygen throughout the
water column using the procedures in Exercise 6.
4. Collect water samples for chemical analyses from (a) inlet sources and (b) the outlet of a lake,
and in the littoral zone among dense stands of aquatic macrophytes. Compare values
obtained from these sources with those from comparable depth in the center of the lake (open
water).
5. Return to the laboratory as promptly as possible and perform the chemical analyses as
discussed above for:
a. Ammonium nitrogen.
b. Nitrate and nitrite nitrogen.
c. Soluble reactive phosphorus.
d. Total phosphorus (particulate and dissolved fractions).
e. Dissolved silica.
f. Major ions, if equipment is available.
g. Specific conductance.
h. Total "dissolved" residues.
Depending on the amount of time available for such analyses, the content of these exercises may
require two or more class periods. Once you are familiar with the methods, the work load can be
divided easily among teams to perform all of the analyses simultaneously.
OPTION 2. LABORATORY EXERCISES
1. From the water samples provided by your instructor, perform the chemical analyses as
discussed earlier in this exercise for:
a. Ammonium nitrogen.
b. Nitrate and nitrite nitrogen.
c. Soluble reactive phosphate.
d. Total phosphorus (particulate and dissolved fractions).
e. Dissolved silica.
f. Major ions, if equipment is available.
g. Specific conductance.
h. Total "dissolved" residues.
Work in teams to perform the analyses simultaneously, then rotate to learn the techniques of
all analyses.