| Summary: | Progress Code: completed Statement: Sea water samples for determining the identity, composition and abundance of protists were obtained using 20 l Niskin bottles (General Oceanics) mounted on a CTD rosette at 30 sites in surface waters (3-12 m depth) and 26 sites at the Chl max (11-80 m) over a total of 34 locations during the BROKE-West survey. Samples were preserved with 1% vol:vol Lugol's iodine and stored in glass bottles, in the dark at 4 degrees C until processing for either light microscopy or electron microscopy. Permanent slides were prepared according to the 2-hydroxypropyl methacrylate (HPMA) (Sigma) method of Crumpton (1981), further modified by Sung-Ho Kang (KORDI, pers. comm.). Each sample was filtered at less than 5 kPa onto a 0.45 micron pore size, 25 mm diameter, GN-6 cellulosic membrane filter (Gelman). The filter was then rinsed by filtering a further 15 ml of MilliQ water, removed from the filtration apparatus and placed face down on a cover glass. A few drops of HPMA were placed on the back of the filter and the sample was then transferred to a 60 degrees C cabinet for 12 to 24 h to clear the filter and polymerise the HPMA. Further drops of HPMA were then placed on the back of the filter, a slide placed on top and the sample again polymerised as above for 6-12 h. Identification of cryptic species was aided by electron microscopy. One litre samples were fixed with 1% glutaraldehyde and stored at 4 degrees C until processed. Each sample was concentrated over a 47 mm diameter 0.8 microns polycarbonate membrane (Poretics) at a vacuum of less than 50 mm Hg and the concentrate resuspended into the sea water remaining above the filter by gentle agitation. For scanning electron microscopy (SEM) cells were settled onto a polylysine-coated glass coverslips, dehydrated with a graded series of acetone, critical point dried, sputter coated with gold and examined using a JEOL JSM 840 SEM. For transmission microscopy (TEM), approximately 40 microlitre aliquots of concentrate were placed on polylysine ...
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