Fresh-water biology /

Abstract

Conditions of existence are of importance only in so far as they affect the life and death processes of organisms. The present 1 The lower part of Pettibone Creek has been destroyed by the United States Naval School, otherwise the table would include the records for a point 5 and perhaps a point 6, but probably not 7.

Population Dynamics of Some Freshwater Zooplankton

“…The authors are indebted to J. L. Brooks for the identification of the Daphnia and to G. W. Comita and M. S. \Vilson for identification of the Diaptomus. For descriptions of these species see Brooks (1957) and Ward and Whipple (1959).…”

The Life of Flathead Lake, Montana

“…Omitting the very specialized parasitic fauna of the lake, its animal organ-20Juday (1916), Reighard, in Ward and Whipple (1918), Steuer (1910) and Whipple (1927). isms include representatives of every phylum, excepting a few, which are mainly, or exclusively marine.…”

Chemical Methods in Slime and Algae Control

“…For purposes of scientific classification, American fresh-water algae are divided into nine classes, namely, Myxophyceae, Rhodophyceae, Heterokontae, Chrysophyceae, Bacillariaceae, Phaeophyceae, Dinophyceae, Chlorophyceae and Euglenophyceae (1). For practical purposes, however, these are usually grouped together as diatoms, blue-green algae (Cyanophyceae) and green algae (Chlorophyceae) (2): As there are several thousand different species belonging to the above groups, the exact identification of any particular organism is a task for an expert. Approximate classification may often be of great practical value, however,…”

“…The amount of oily matter required to produce a distinct odor is remarkably small, and may be detected in some cases when diluted with as much as twenty-five million parts of water. The odors are intensified by any violent physical change which tends to rupture the cell walls and liberate the oil droplets (2). The use of copper sulfate to kill algae growths may result in the liberation of odors and tastes.…”

“…As algae will not grow in the dark, covering of reservoirs has been proposed and this is apparently quite effective. Other organisms, particularly Crenothrix, will grow in the dark, so only troubles due to green algae can be controlled in this way (2). Algae are killed by ultraviolet light when sufficiently exposed (12), and while this is not a very practical method of destruction, it is occasionally used.…”