Historical Records of Changes in the Productivity of Lakes
343
what is known about the effects of contemporary lake responses to increased or decreased
loading of phosphorus? Elaborate.
5. If one knew in sufficient detail the species of diatoms found in sediments, as well as that
certain diatoms were usually littoral or nearly always pelagic, how might the stratigraphy of
diatoms help to explain past changes in the lake? What events could lead to fluctuations in
littoral versus pelagic development of algae? [See. e.g., Manny et al. (\978).]
6. How would one accurately evaluate the rates of sedimentation to lake sediments? How
would radiocarbon dating help interpretations? Pollen stratigraphy?
7. Why is it important to know the rates of sedimentation when attempting to interpret the
chemical and biological properties of sediments over time?
8. How does differential dissolution of diatom frustules confound use of their remains as a
paleolimnological parameter? What factors in the ontogeny of a lake might alter the
preservation of diatoms?
9. What factors within the lake influence the deposition and the preserva~ion of pigment
degradation products in sediments [see, for example, Wetzel (1970), Daley (1973), and Daley
and Brown (1973)].
10. What, and how would, certain morphological remains of animals be useful in the
interpretation of past lake conditions? [See e.g., Frey (1974), and Crisman (1978).]
Morphological remains of higher aquatic plants? [See Birks and Birks (1980).]
11. Discuss the usefulness of reporting data as percent oftotal as opposed to deposition per unit
area.
Apparatus and Supplies
1. Coring device with several plastic liners, cable, stoppers to seal ends, and storage rack to keep
liners vertical.
2. Extruding stopper, mounted on a rod, to fit tightly inside of plastic liners.
3. Meter rulers and marking pens.
4. A number of clean spatulas and knives and clean sample vials.
5. 90% aqueous, basic acetone (see Exercise 10), dimethylaniline (Caution: toxic), methanolic
potassium hydroxide, methanol, petroleum ether, separatory funnels, test tubes (25 x
150mm), Parafilm, glass funnels, Whatman No. 50 filter paper, lOO-ml ground-glassstoppered graduated cylinders, and spectrophotometer.
6. Crucibles, tongs, 105°C oven, 550°C mume furnace, analytical balance, and desiccators.
7. 100-ml volumetric flasks, reagents and supplies for total phosphorus analysis (see Exercise 7),
and clinical centrifuge.
8. Diatom analyses: Concentrated HN0 3, K 2 Cr20 7, beakers, protective face wear and hood,
litmus paper, low temperature hot plate with aluminum block or heavy aluminum sheeting,
micropipets, and Hyrax mounting medium.
9. Pollen analyses: 3N HCI, centrifuge, polypropylene centrifuge tubes, 10% KOH, absolute and
95% ethanol, 0.2-mm mesh sieve, glacial acetic acid, acetic anhydride, concentrated H 2S04 ,
glass stirring rods, boiling water bath, tertiary butyl alcohol or benzene.
References
Birks, H.J.B. and H.H. Birks. 1980. Plant macrofossils in quaternary lake sediments. Arch.
Hydrobiol. Ergebn. LimnoI15.60pp.
Brown, C.A. 1960. Palynological Techniques. C.A. Brown, 1180 Stanford Ave., Baton Rouge,
LA. 188pp.
Crisman, T.L. 1978. Reconstruction of past lacustrine environments based on the remains of
aquatic invertebrates. In: D. Walker, Editor. Biology and Quarternary Environments.
Australian Acad. Sciences, Canberra.
Daley, R.J. 1973. Experimental characterization of lacustrine chlorophyll diagenesis. II.
Bacterial, viral and herbivore grazing effects. Arch. Hydrobiol. 72:409-439.
343
what is known about the effects of contemporary lake responses to increased or decreased
loading of phosphorus? Elaborate.
5. If one knew in sufficient detail the species of diatoms found in sediments, as well as that
certain diatoms were usually littoral or nearly always pelagic, how might the stratigraphy of
diatoms help to explain past changes in the lake? What events could lead to fluctuations in
littoral versus pelagic development of algae? [See. e.g., Manny et al. (\978).]
6. How would one accurately evaluate the rates of sedimentation to lake sediments? How
would radiocarbon dating help interpretations? Pollen stratigraphy?
7. Why is it important to know the rates of sedimentation when attempting to interpret the
chemical and biological properties of sediments over time?
8. How does differential dissolution of diatom frustules confound use of their remains as a
paleolimnological parameter? What factors in the ontogeny of a lake might alter the
preservation of diatoms?
9. What factors within the lake influence the deposition and the preserva~ion of pigment
degradation products in sediments [see, for example, Wetzel (1970), Daley (1973), and Daley
and Brown (1973)].
10. What, and how would, certain morphological remains of animals be useful in the
interpretation of past lake conditions? [See e.g., Frey (1974), and Crisman (1978).]
Morphological remains of higher aquatic plants? [See Birks and Birks (1980).]
11. Discuss the usefulness of reporting data as percent oftotal as opposed to deposition per unit
area.
Apparatus and Supplies
1. Coring device with several plastic liners, cable, stoppers to seal ends, and storage rack to keep
liners vertical.
2. Extruding stopper, mounted on a rod, to fit tightly inside of plastic liners.
3. Meter rulers and marking pens.
4. A number of clean spatulas and knives and clean sample vials.
5. 90% aqueous, basic acetone (see Exercise 10), dimethylaniline (Caution: toxic), methanolic
potassium hydroxide, methanol, petroleum ether, separatory funnels, test tubes (25 x
150mm), Parafilm, glass funnels, Whatman No. 50 filter paper, lOO-ml ground-glassstoppered graduated cylinders, and spectrophotometer.
6. Crucibles, tongs, 105°C oven, 550°C mume furnace, analytical balance, and desiccators.
7. 100-ml volumetric flasks, reagents and supplies for total phosphorus analysis (see Exercise 7),
and clinical centrifuge.
8. Diatom analyses: Concentrated HN0 3, K 2 Cr20 7, beakers, protective face wear and hood,
litmus paper, low temperature hot plate with aluminum block or heavy aluminum sheeting,
micropipets, and Hyrax mounting medium.
9. Pollen analyses: 3N HCI, centrifuge, polypropylene centrifuge tubes, 10% KOH, absolute and
95% ethanol, 0.2-mm mesh sieve, glacial acetic acid, acetic anhydride, concentrated H 2S04 ,
glass stirring rods, boiling water bath, tertiary butyl alcohol or benzene.
References
Birks, H.J.B. and H.H. Birks. 1980. Plant macrofossils in quaternary lake sediments. Arch.
Hydrobiol. Ergebn. LimnoI15.60pp.
Brown, C.A. 1960. Palynological Techniques. C.A. Brown, 1180 Stanford Ave., Baton Rouge,
LA. 188pp.
Crisman, T.L. 1978. Reconstruction of past lacustrine environments based on the remains of
aquatic invertebrates. In: D. Walker, Editor. Biology and Quarternary Environments.
Australian Acad. Sciences, Canberra.
Daley, R.J. 1973. Experimental characterization of lacustrine chlorophyll diagenesis. II.
Bacterial, viral and herbivore grazing effects. Arch. Hydrobiol. 72:409-439.