Cluster analysis of potomac river survey stations based on protozoan presence-absence data
✍ Scribed by John Cairns; Roger L. Kaesler
- Publisher
- Springer
- Year
- 1969
- Tongue
- English
- Weight
- 849 KB
- Volume
- 34
- Category
- Article
- ISSN
- 1573-5141
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✦ Synopsis
Four high-water and six low-water limnological surveys of a portion of the Potomac River were made from 1956 to 1965 ; samples were collected at three stations on each survey to determine the effects of operation of the PEPCO Dickerson Power Station on the aquatic biota . Cluster analyses were made of various combinations of Jaccard coefficients relating 46 aggregations of 647 protozoan species .
Similarities of aggregations of species within a survey were nearly always greater than similarities among aggregations from different surveys, indicating linear or along-stream environmental influences . Within-survey similarities for the early and late surveys were usually higher than similarities within middle-year surveys, a possible indication of environmental change at all stations, including the control, and subsequent biotic readjustment . Clustering of the 1956 aggregations, taken under high-water conditions before plant operations began, with aggregations from other surveys for any one station indicate that 1956 may have been different from other survey years . One explanation is that increased urbanization upstream from the power station after 1956 caused some environmental change . No changes in aquatic biota could be attributed to thermal pollution as a direct result of operation of the electric power generating station .