58 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I28 



PLANKTON SAMPLING, SUMMER 



During the summer of 1948 plankton hauls were made from a skiflf 

 propelled by rowing, or from a grounded ice floe. During the sum- 

 mers of 1949 and 1950 plankton tows were taken from a skifif, but 

 launching a skifif was not always feasible or practicable, as the surf 

 was often too heavy. Consequently, tows had to be made when condi- 

 tions were favorable rather than at stated intervals or at the most 

 desirable times. Sometimes ice floes were grounded in such a man- 

 ner that by walking to the outer edge and throwing a plankton net as 

 far as possible satisfactory plankton samples could be obtained. 



Occasionally samples could be taken on calm days by casting a net 

 from the shore, but this method was not satisfactory because the 

 gradual slope of the bottom made it almost impossible to get the net 

 into water of sufficient depth. 



PLANKTON SAMPLING, WINTER 



After the ocean froze over, plankton samples were taken through 

 holes in the ice. Several stations were maintained throughout the 

 winter at various distances from shore (see "Trapping Through the 

 Ice"), but the one most frequently used was over 80 feet of water at 

 1.6 miles from shore. This station was used from January to the first 

 part of July 1950, inclusive. Holes farther from shore were destroyed 

 by the movement of ice and in some instances could not be used more 

 than a few weeks. 



In order to make the sampling as uniform as possible and thus 

 obtain information on the relative quantitative changes taking place 

 in the winter months, a definite procedure was followed. First, if the 

 hole had frozen over, the ice had to be broken and removed with a 

 large sieve-dipper ; or if not completely frozen over there was always 

 slush ice to be dipped out. A plankton net with a flask attached was 

 then lowered to the bottom and towed vertically to the surface. This 

 was done three times. When the flask was brought up it had to be 

 thickly wrapped in insulating material for transportation to the 

 laboratory. 



There was also the problem of preventing the net from freezing 

 solid as soon as it became wet, thus closing the meshes so that the 

 water would not drain out. The only satisfactory method of pre- 

 venting this was to pour into the hole a pailful of hot water, which 

 warmed the surface water sufficiently to keep the net from freezing 

 when lowered, and another pailful just before the net was withdrawn. 

 A stove for heating the water was housed in a snow house (pi. 4, 



