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

This portion of the program is admittedly experimental. We do not yet
know whether it will produce the desired results.
An Undesirable New Alga in the Cook Plant Phytoplankton. On 10 July 1970
the first full-scale biological survey of the Cook Plant area was carried out.
Included in this survey were 52 phytoplankton samples, the analyses of which
are only now being completed.
At Station SDC-1-2 of this survey the phytoplankton sample obtained at
1-meter depth in milky brownish-green water (that we believe is St. Joseph
River water) contained abundant numbers of what appear to be a strange dinoflagellate alga hitherto not reported from Lake Michigan, and only twice previously reported from the United States. In its full blooms this alga produces
milky water color, disagreeable odor, and thick white surface "flocs" that
interfere with recreational activities.
Ahearn, Hall, and Reinhardt (1971) report blooms of this Hypnodiniumlike alga in lakes in Georgia river systems in 1968, 1969, and 1970. In the
Georgia lakes the blooms appear to be related to both the beginning of summer
thermal stratification and to inputs of sewage, both of which conditions can
be met in St. Joseph River water discharged into Lake Michigan. Their complete
paper is included as page 18.
Occurrences of milky water have been widespread in Lake Michigan since
1966. The milky water of Lake Michigan has not involved a white surface scum
nor has it been relatable to influents of sewage. There is no evidence at this
time that the milky water color of Lake Michigan is related to the presence
of this organism. This organism, however, with its undesirable bloom characteristics, is one for which careful watch will be kept in subsequent phytoplankton
analyses.

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