Studies on the Effects of Thermal Additions on Selected Zooplankton Populations

Abstract

The objective of this study was to examine the effects of calefaction upon members of the animal portion of the Lake Superior ecosystem. Additionally, certain species which are widely available were also utilized in order to establish a point of reference which could be used by workers in other parts of the country. The conventional approach to a problem of this sort has been to measure the effects of an effluent source on a specific community and attempt to understand the ecological interrelationships of the altered environment. The method described here utilized the establishment of an artificial segment of Lake Superior in a carefully controlled laboratory setting which could be modified at will in order to observe the impacts of each change upon the test organism or community. Critical to this study was a method of observation of organism behavior which allowed remote monitoring of the population, but did not alter the environment of the test animals. Such a methods was developed and is described in a succeeding section. This method enabled measurement of critical physiological and behavioral responses which provided a baseline for work with thermal additions.