Cook Plant preoperational studies 1970 / John C. Ayers ... [et al.].

The rest of the data were collected by quantitative settling-out of phytoplankters from a liter of water after preservation with Utermohl's iodine
fixative. Depths of sampling in the latter stations range from just under the
surface to 15 meters.
The following rough beginning of the Cook site annual cycle of planktonic
algal water quality is presented as that cycle which will be supplemented and
developed as additional data become available.
In the summary of the planktonic algae in Table 7 we define: Winter as
being December, January, and February; Spring as being March, April, and May;
Summer as being June, July, and August; and Fall as consisting of September,
October, and November. Samples during winter are at present impossible for
us.
We can make the following comments about these data: 1) evidence from
the Chicago Water Department indicates in their nearshore water a heavy dominance of diatoms during winter, consequently we do not consider that the May
1970 diatom abundance is a yearly maximum; 2) there appears to be an increase
(in numbers of species, at least) of blue-green algae from spring into fall;
3) green algae appear to have a peak in late summer that may or may not be
supported by subsequent data; and 4) the persistence of flagellates is unexpected and may or may not be supported by subsequent data.
Statistical Treatment of Phytoplankton Records. The phytoplankton
records of the Cook Plant surveys are by far the most difficult to interpret
of all the data being obtained, yet they are probably the most sensitive indicators of water quality. Statistical aids to their interpretation are considered necessary.
We propose to try the computation and interpretation of the diversity
index, or such other parameters as informed statisticians may devise, to see

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