Phytoplankton of the seasonal surveys of 1977, and further pre- vs. post-operational comparisons at Cook Nuclear Plant / John C. Ayers, Susan J. Wiley.

1977
Apr. 2 3
July 2 1 4
Oct. i 1 a
4 4 9
Except for the greater number of dominant and codominant blue-greens in
1976, the numbers and types of dominants and codominants during the
operational years are within the range of normal variation established in the
preoperational years. It is unlikely that the increased blue-greens in 1976
were an effect of plant operation, for they returned to the normal range of
numbers in 1977 when the plant operated at full power for much more of the
year than it had in 1976.
Beginning in 1972 there has been a trend toward increasing numbers of
blue-green algae as dominants and codominants. This conforms with the
findings by Tarapohak and Stoermer (1976) and others that in recent years
blue-greens have increased in Lake Michigan as a result of summer depletion
of silica in the epilimnion. Heavy dominance by the blue-greens Anacvstis
incerta and Gomphosphaeria lacustris first appeared in October 1974 and has
been characteristic of Octobers in subsequent years. It is attributable to
summer silica depletion, not to any effect of plant operation.
Master Lists of PhvtopLankters Collected
Appendix C presents the lists of phytoplankters collected in the
seasonal surveys of 1977. Ayers (1978) lists the collections of 1976 and
previously unreported September 1970. Ayers, Southwick, and Robinson (1977)
give the master lists for the surveys of 1974 and 1975. Ayers (1975)
presents the lists for the surveys of 1972 and 1973. Ayers, Mozley, and
Stewart (1974) list the species collected in the seasonal surveys of 1971.
Ayers, Mozley, and Roth (1973) give the master list for November 1970. Ayers

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