2j-5i,«k~* -^'j ■»w^»r 



FIGURE |0*0 



HIGH SPEED PLANKTON 



SAMPLER 



re nozzle" type 



In many cases there is now a need to bring the organisms back 

 to the laboratory alive. This has been done successfully at our 

 laboratory by removing the organisms from the plankton catch and 

 placing them into small plastic containers and into a refrigerated 

 box. Such a procedure is highly satisfactory for surface catches 

 of zooplankton; organisms have been kept for 2- to 3-nnonth periods. 

 There is little chance that the deepwater plankton, however, can 

 survive the ascent of the net from deep, cold water through the 

 warm surface layers of temperate and tropical waters. The severe 

 thermal shock is so great using our present techniques that we 

 are denied access to these animals for careful physiological or 

 biochemical studies. 



I have reviewed generally the nature of the collecting tech- 

 niques used in plankton biology; now I will be more specific with 

 regard to the instrumentation for obtaining the larger zooplank- 

 ton from various depths throughout the water column. Our present 



204 



