Bacteria and phytoplankton of the seasonal surveys of 1972 and 1973 / John C. Ayers.

settled overnight, the aluminum plate on which they rest is placed on a
block of dry ice for 90 seconds. This freezes the bottom 1-1.5 ml. The
unfrozen part is then discarded and the cylinders are removed from the
slides. The slides are then placed in an anhydrous ethanol chamber for
3 days and then in a toluene chamber for 1 day.
The first chamber removes the excess water and the second prepares
the samples for their final mounting in toluene based Permount. One drop
of Permount is put on the slide, a cover slip is then placed over it and
the slide is allowed to dry for 2 days.
The specimens are counted, at 100OX under oil immersion on a Leitz
Ortholux microscope, to species when practical, otherwise to genus or
group. Only those specimens that appear to have been viable at the time
of collection are counted. Two sweeps of the slide are made, one vertical and one horizontal. This provides an indication of the randomness
of the species on the slide.
Counts are calculated as cells per liter, but are divided by 1000
in the computer print-outs.
Solitary species, green and blue-green algae colonies, and the
filaments of filamentous forms were each counted as one cell. Each
colonial diatom cell was counted except when the size of the filaments or
colonies prohibited counting the individual cells; in this case, the
number of individual cells was estimated.
Species and forms are presented in the way in which they are recognized and counted. Examples are: GZenodinium, a dinoflagellate, is
recognized and counted separately from unidentified dinoflagellates
which are given as "Dinoflagellates"; the flagellates Cryptomonas and
ChZamydomonas are recognized and counted separately from unidentified
"Flagellates"; Anacystis and Chroococcus are recognized as separate
entities, rather than as species of Anacystis.
Results
April 1972 samples from most of the SDC stations were lost due to
unexplainable failure of preservation.

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