Reed College Canyon

A Study of the Diatoms in Reed College Lake

author: Eleanor Arlene Danielson
advisor: Alan M. MacEwan
year: 1951

SUMMARY: On the basis of the available literature, a discussion of the structure, characteristics, reproduction, environmental requirements and basis of classification of diatoms is given as a general background.

Twenty-three genera occurring in the Reed College Lake were identified. These genera are listed and are discussed in connection with the habitats in which they were found.

Diatoms in varying abundance were found at all times on the lake bottom, submerged leaves and other objects, but very few diatoms were found in the open water of the lake.

Observations indicated that temperature and pH do not vary enough from one part of the lake to another to be responsible for population differences and that illuminations and rising temperatures appear to be factors partially responsible for a spring diatom maximum.

Differences of illumination on the north and south sides of the lake apparently did not affect the winter samples. In the early spring samples the diatom maximum occurred first on the well lighted north side. The later spring samples showed better growth in the more shaded areas. A harmful effect of too much light is suggested.

It was found that the storage of diatom cultures for protracted periods in the refrigerator, on an inside window ledge and on the outside is unsatisfactory, but samples may be kept in the refrigerator or other cool place overnight with no apparent harmful effects.

A satisfactory method for viewing both the girdle and valve is presented.