Diane Stoecker notes:

 Samples obtained by filtering 37 to 55.5 liters of water from Niskin bottles
 using a modified Buchner funnel with a 20 um nitex mesh screen.  Samples
 were preserved with 20% buffered formalin.  Strontium chloride was added
 to aid with acantharian preservation.  Samples stored in dark and
 refrigerated.