METHODS 



MACROPLANKTON 



SAMPLING 



The larger and more sparse macroplankton were 

 sampled by the following method. The instrument cart was 

 lowered to within 2 feet of the bottom, time was allowed for 

 the water already present in the hose to be pumped out, and 

 a 5-gallon sample was passed through a plankton net 

 (Kahlsico No. 1520) hung with 20-gauge nylon gauze. Water 

 pumped and filtered was caught and measured in a stainless 

 steel container. The catch concentrated in the cod-end 

 bucket was washed into 8-ounce bottles and fixed in 10- 

 percent formalin. 



The procedure was repeated every 10 feet through 

 the water column until six samples were obtained. The 

 last sample was taken 52 feet from the bottom and varied 

 with respect to distance from the sea surface according to 

 tide and wave action. Depth positioning from a fixed plat- 

 form in a shallow environment is more consistent relative 

 to the bottom than depth positioning from a constantly 

 changing surface. Vertical sampling series for naacro- 

 plankton took about 30 minutes. 



FIXING AND COUNTING 



The formalin-fixed macroplankton samples were 

 concentrated through a piece of 20-gauge nylon netting 

 identical to that used in the net and backwashed into 10-ml 

 attenuated centrifuge tubes (fig. 3). When the samples had 

 settled for about 1 hour, the wet displacement was measured 

 and the material withdrawn in a large-bore pipette. Placed 

 in a long plastic trough (fig. 4), the entire sample was 

 counted under a magnification of 23 diameters. At this 

 power, the width of the trough is slightly less than the 



