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

phytoplankton of Zone 1.
In Zone 2, parallelism between the curves of abundances at inner and outer
stations has been, with the exception of July 1977, generally good since 1972.
Except for July 1975 and October 1977, abundances of total algae have been
greater at the inner stations in the operational-year surveys. With the
plant's waste heat plume in Zone 1 most or all of the time, it would be
unrealistic to attribute to plant heat the generally higher abundances at the
inner stations of Zone 2. Abundances of total algae in both inner and outer
stations of this offshore zone have been increasing quite consistently since
1971. Beginning during preoperation and continuing into the operational years,
the increasing abundances reflect some change in the lake itself, rather than
effects of plant operation.
In the time sequences of total phytoplankton abundances there is no
convincing evidence that Cook Plant operation has affected the local community;
the changes observed appear to be expressions of the lake's continuing
eutrophication.
Inner-Outer Statistical Comparisons: Phvtoplankton Abundances by Algal
Categories. 1970-1977
Ayers (1978) reported preliminary statistical tests on total phytoplankton
abundances (densities in cells per ml) at inner and outer station groups of
shallow Zone 0 and deep Zone 2 in the years 1970 through 1976. The test used
was the 2-sample Students t test. This section expands those preliminary
statistical tests to include all ten categories of algae, the intermediate
depth zone (Zone 1), and all three zones in the year 1977.
The strategy was that if plant-caused effects on the phytoplankton were
present they could be expected to show consistent significant differences in

68