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

We have succeeded in developing what appears to be an adequate chamber
for the microscope stage. It withstands city-supply water pressure without
leakage, it apparently does not develop flow separation, and it has desirable
qualities of not clogging in turbid-water conditions.
We have, however, found that the common commercially available sources
of ultraviolet light are deficient in intensity, and that they contain substantial amounts of non-ultraviolet light which must be filtered out. The
photomultipliers so far tried are unacceptably noisy under the direct ultraviolet lighting conditions which have been tried.
We continue to investigate sources of more intense and better spectrallycontrolled ultraviolet-light sources. It is planned to reconfigure the instrument to avoid having the photomultiplier look directly at the light source.
We are also planning to combine a Turner fluorometer with a Hiac particle
counter as an interim measure.
A.4 Study of Attached Algae
Initial Periphyton Samples. Two periphyton samples were obtained on
21 October from plastic subsurface floats attached to periphyton collectors
that had not been successful. The collectors had been set on 23 September.
The plastic subsurface floats were at depths of about six feet; their function
was to aid our divers in finding the collectors. The floats had a smooth
surface finish from which the periphyton were scraped.
The samples are qualitative only, but are adjudged adequate to indicate
the dominant periphyton types native to the Cook Plant area in fall.
The periphyton was very sparse, and was heavily dominated by diatoms of
the genera Gomphonema, Nitzschia, Synedra, Achnanthes, and Cymbe la. The
dominant diatom was Gomphonema sp., though Melosira varians (a supposed
pollution indicator) was also quite abundant.

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