The Effects of a Thermal Discharge on the Inshore Biological Communities of Lake Michigan

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Spigarelli, S. A.
Prepejchal, W.
Lake Michigan ; Point Beach Nuclear Power Station ; Benthos ; Periphyton ; Plankton ; nutrient concentration ; Thermal Discharge
The plankton, peripnyton, and benthos communities of inshore waters were studied near the Point Beach Nuclear Power Station during 1971 to determine the biological effects of once-through cooling. These aquatic communities are characteristically vital in the trophic system as primary producers (periphyton and phytoplankton), consumers, and food organisms for other animals. Alteration cf photo synthetic activity or food chain relationships could result in detrimental impact to the local inshore ecology near a thermal discharge. It is evident from a review of the literature that the extent of biological impact due to thermal discharges varies tremendously and depends upon the aquatic habitat, species compositions, and specific operational criteria of the generating station. Although it is often possible to demonstrate an effect on a species or functional group of organisms, it is extremely difficult to evaluate the overall significance (impact) of that effect on the ecology of Lake Michigan. The approach of these preliminary studies was to search for measurable effects on the communities of local inshore waters which would warrant future study based on the potential significance of those effects .
TABLE 1. Physical and Biological Measurements at Point Beach Nuclear Power Station.; FIG. 1.—Chlorophyll a fluorescence of phytoplankton samples from plume stations near Point Beach Nuclear Power Station.; FIG. 2.—Periphyton growth at Point Beach Nuclear Power Station during late summer (85-day growth period) and fall (141-day growth period).