Seawater samples in all cases were analyzed for 

 dissolved oxygen, nitrogen, and carbon monoxide by the 

 gasometric method of Scholander et al . 5 This method gener- 

 ally requires a 1-cc sample from which the dissolved gases 

 may be determined with an accuracy of 2 percent of the theo- 

 retical value (as checked against air -equilibrated water). 

 With proper technique the precision of gas extraction from 

 duplicate samples is better than ±2 percent (average of four 

 test extractions = 1.7 percent) or ±0.3 mm 3 of the total 

 extracted gas equivalent to ±0.4 ppm in the case of oxygen. 

 The precision of duplicate analyses for dissolved oxygen, 

 carbon monoxide, or nitrogen averages ±0. 3 mm 3 (deter- 

 mined from four sets of test analyses) which at its worst is 

 an error of only about 3 percent (see Appendix A for further 

 discussion of analytical techniques and sources of error). 



All pneumatophores and intact siphonophore speci- 

 mens were weighed on an analytical balance to ±0. 1 mg. 

 Weights reported are "blotted wet weights, " that is, the 

 specimen was either gently rid of adhering surface liquid 

 and then weighed in a previously weighed water drop; or 

 weighed with adhering moisture, gently blotted, and the 

 blotting (filter) paper with absorbed moisture weighed 

 separately. Subtraction of the latter value provides the 

 weight of the "blotted" specimen. 



Measurements of Oxygen Consumption 

 by Micrometer Respirometer 



This method, devised originally by Scholander, 

 provides a volumetric means of following the oxygen con- 

 sumption of very small organisms, tissues, or cell suspen- 

 sions (fig. 5). The spindle of a standard metric micrometer 

 is replaced with a 1/16 -inch drill rod which travels into a 

 mercury reservoir. Movement of this "micro spindle" into 

 or out of the reservoir controls the position of an indicator 

 drop in a capillary opposite the reservoir. As an organism 

 in the reaction vessel consumes oxygen from the air, the 

 indicator drop travels toward the "T. " Setting the drop 

 back to the reference line by adjustment of the micrometer 

 gives an indication of oxygen consumed in the time interval 

 in question. The bulb, closed by a polyethylene -tipped, 



12 



