288
Exercise 21
10. What are the possible fates ofDOM leached from POM and decomposing POM, and POM
detrital plant materials entering a stream? [See Fisher and Likens (1973) and Wetzel and
Manny (1972).]
11. What chemical and metabolic pathways could be involved in the shifting ofDOM to POM?
[See Lush and Hynes (1973) and Lock and Hynes (1976).]
12. How do anaerobic conditions affect the rates of decomposition of macrophytes? Affect the
methods of measuring in situ rates of decomposition by the analysis of gaseous metabolic end
products?
13. Is the microhabitat within a leaf pack in a flowing stream necessarily aerobic? Why?
14. What is the role of invertebrates in the decomposition of particulate organic matter?
IS. Compare decomposition rates and processes in freshwater and marine environments. [See
Capone and Kiene (1988).]
Apparatus and Supplies
1. Phytoplankton mineralization
a. Nonmetallic water sampler; thermistor thermometer.
b. 2.S-1 bottles (ground-glass-stoppered); suspension clips, line, and buoy; anchor for buoy.
c. NaH 14C03 stock solution.
d. Filtration apparatus; precombusted ~OO°C) glass fiber filters (e.g., Whatman GF/F);
chamber for exposing filters to fumes of HCI (see Exercise 14); desiccator; membrane
filters (0.4S-llm pore size).
e. CO2 or CO2-enriched air; N2 gas.
f. SO°C oven or block heater (or lyophilization apparatus).
g. 300-ml ground-glass-stoppered BOD (Biological Oxygen Demand) bottles, made opaque
with black electrician's tape or aluminum foil.
h. Apparatus for measuring dissolved inorganic carbon (see Exercise 8).
i. Nz-sparging apparatus (as illustrated in Fig. 21.2); ethanolamine-methyl cellosolve (or
similar, Exercise 20) CO2-trapping agent; scintillation solution (e.g., 2: I toluene: 2methoxyethanol plus 6 g PPO/1); liquid scintillation radioassay instrumentation.
2. Decomposition of macrophytes
a. Tape rule (ca. 30 m); clippers, scissors; wooden stakes (ca 1 m long).
b. Balance; drying oven (10S°C); aluminum foil; nylon monofilament line; nylon mesh (ca. 2mm mesh); desiccator
c. Apparatus and supplies for analyses of organic carbon, nitrogen, and phosphorus
(optional) (see Exercises 7, 9, and 27).
3. Decomposition of leaves in streams:
a. Construction bricks (with holes); nylon monofilament line; metal stakes, if needed; nylon
mesh (ca. 1.0-mm mesh).
b. Balance; drying oven (lOS°C); aluminum foil; desiccator.
c. Apparatus and supplies for analyses of organic carbon, nitrogen, and phosphorus
(optional) (see Exercises 7, 9, and 27).
References
Alexander, M. 1965. Biodegradation: Problems of molecular recalcitrance and microbial
fallibility. Adv. Appl. Microbiol. 7: 3S-80.
Bilby, R.E., and G.E. Likens. 1980. Importance of organic debris dams in the structure and
function of stream ecosystems. Ecology 61: 1107-1113.
Capone, D.G. and R.P. Kiene. 1988. Comparison of microbial dynamics in marine and
freshwater sediments. Contrasts in anaerobic carbon metabolism. Limnol. Oceanogr. 33: 72S749.
Cole, 1.1. 1985. Decomposition. pp. 302-310. In: G.E. Likens, Editor. An Ecosystem Approach to
Aquatic Ecology: Mirror Lake and Its Environment. Springer-Verlag, New York.
Exercise 21
10. What are the possible fates ofDOM leached from POM and decomposing POM, and POM
detrital plant materials entering a stream? [See Fisher and Likens (1973) and Wetzel and
Manny (1972).]
11. What chemical and metabolic pathways could be involved in the shifting ofDOM to POM?
[See Lush and Hynes (1973) and Lock and Hynes (1976).]
12. How do anaerobic conditions affect the rates of decomposition of macrophytes? Affect the
methods of measuring in situ rates of decomposition by the analysis of gaseous metabolic end
products?
13. Is the microhabitat within a leaf pack in a flowing stream necessarily aerobic? Why?
14. What is the role of invertebrates in the decomposition of particulate organic matter?
IS. Compare decomposition rates and processes in freshwater and marine environments. [See
Capone and Kiene (1988).]
Apparatus and Supplies
1. Phytoplankton mineralization
a. Nonmetallic water sampler; thermistor thermometer.
b. 2.S-1 bottles (ground-glass-stoppered); suspension clips, line, and buoy; anchor for buoy.
c. NaH 14C03 stock solution.
d. Filtration apparatus; precombusted ~OO°C) glass fiber filters (e.g., Whatman GF/F);
chamber for exposing filters to fumes of HCI (see Exercise 14); desiccator; membrane
filters (0.4S-llm pore size).
e. CO2 or CO2-enriched air; N2 gas.
f. SO°C oven or block heater (or lyophilization apparatus).
g. 300-ml ground-glass-stoppered BOD (Biological Oxygen Demand) bottles, made opaque
with black electrician's tape or aluminum foil.
h. Apparatus for measuring dissolved inorganic carbon (see Exercise 8).
i. Nz-sparging apparatus (as illustrated in Fig. 21.2); ethanolamine-methyl cellosolve (or
similar, Exercise 20) CO2-trapping agent; scintillation solution (e.g., 2: I toluene: 2methoxyethanol plus 6 g PPO/1); liquid scintillation radioassay instrumentation.
2. Decomposition of macrophytes
a. Tape rule (ca. 30 m); clippers, scissors; wooden stakes (ca 1 m long).
b. Balance; drying oven (10S°C); aluminum foil; nylon monofilament line; nylon mesh (ca. 2mm mesh); desiccator
c. Apparatus and supplies for analyses of organic carbon, nitrogen, and phosphorus
(optional) (see Exercises 7, 9, and 27).
3. Decomposition of leaves in streams:
a. Construction bricks (with holes); nylon monofilament line; metal stakes, if needed; nylon
mesh (ca. 1.0-mm mesh).
b. Balance; drying oven (lOS°C); aluminum foil; desiccator.
c. Apparatus and supplies for analyses of organic carbon, nitrogen, and phosphorus
(optional) (see Exercises 7, 9, and 27).
References
Alexander, M. 1965. Biodegradation: Problems of molecular recalcitrance and microbial
fallibility. Adv. Appl. Microbiol. 7: 3S-80.
Bilby, R.E., and G.E. Likens. 1980. Importance of organic debris dams in the structure and
function of stream ecosystems. Ecology 61: 1107-1113.
Capone, D.G. and R.P. Kiene. 1988. Comparison of microbial dynamics in marine and
freshwater sediments. Contrasts in anaerobic carbon metabolism. Limnol. Oceanogr. 33: 72S749.
Cole, 1.1. 1985. Decomposition. pp. 302-310. In: G.E. Likens, Editor. An Ecosystem Approach to
Aquatic Ecology: Mirror Lake and Its Environment. Springer-Verlag, New York.