Observations on the Nutrient Concentrations in the Northern 

 Region of Baffin Bay and the Kane Basin, Summer 1963 



David A. McGill and Nathaniel Corwin 1 



Woods Hole Oceanograpkic Institution 

 Woods Hole, Massachusetts 



An ice jam in the Kennedy Channel in the spring 

 of 1963 led to open water in the Kane Basin and 

 the northern reaches of Baffin Bay, opening this 

 area for survey work for the first time in many 

 years. Nutt and Coachman (1963) have described 

 the conditions existing at the time when hydro- 

 graphic observations were made by the USCGC 

 Evergreen following its regular annual cruises in 

 more southern waters. In addition to routine ob- 

 servations of temperature, salinity, and oxygen 

 distribution, samples were taken for analysis of 

 various nutrients. The Danish Godthaab expedi- 

 tion of 1928 (Hagen, 1936) provides a limited cov- 

 erage of the nutrient distribution in the area, but 

 analytical techniques have greatly improved since 

 that date. The only other pertinent data on the 

 levels of concentration of nutrients that we have 

 been able to locate occur in the reports from the 

 various ice islands in the Arctic Ocean. Our re- 

 sults represent the most comprehensive coverage 

 available for the area, and therefore the distribu- 

 tion of the quantities observed will be presented in 

 detail. 



Methods 



Sea water samples were collected on station in 

 8-ounce plax bottles and stored in deep-freeze 

 lockers for the duration of the cruise. The analy- 

 ses were carried out by the authors at the "Woods 

 Hole Oceanographic Institution, with the assist- 

 ance of Mr. John Schilling and Mrs. Juanita Mo- 

 gardo. Inorganic phosphate and total phosphorus 



1 This work has been supported in part by the Office of 

 Naval Research under contract Nonr 2196 (00) NR 083- 

 004. Contribution No. 1506 from the Woods Hole Oceano- 

 graphic Institution. 



determinations were made for all samples. Ni- 

 trate- and nitrite-nitrogen, and silicate-silicon con- 

 centrations were also measured. The techniques 

 employed are summarized as follows : 



Inorganic phosphate was determined by the use 

 of ascorbic acid to reduce the phospho-molybdic 

 complex formed with acidic molybdate solution 

 (Murphy and Riley, 1962) . The presence of anti- 

 mony tartrate promotes more rapid color develop- 

 ment and the color, once formed, is stable for long 

 periods. Measurements were made using a model 

 DU spectrophotometer with a 10-cm light path at 

 900 m/x. 



Total phosphorus was analyzed by the modified 

 Harvey method described by Ketchum, Corwin, 

 and Keen (1955). Following digestion in a steam 

 autoclave for 5 hours at a pressure of 40 lbs./sq. in., 

 samples were determined colorimetrically for the 

 molybdate complex as with the inorganic phos- 

 phate method, but using a stannous chloride solu- 

 tion as the reducing agent. 



Nitrate-nitrogen was determined following re- 

 duction with hydrazine in the presence of copper, 

 according to the method of Mullin and Riley 

 (1955a). Samples were read on a DU spectro- 

 photometer at 524 m/i. The value obtained is the 

 total of both the nitrate and nitrite present in a 

 sample. 



Nitrite-nitrogen was measured colorimetrically 

 following diazotization with sulfanilic acid 

 coupling with alphanaphthylamine, according to 

 the method of Rider and Mellon ( 1946) . The sam- 

 ple was read on a DU spectrophotometer at 

 520 m/i. 



Silicate-silicon was also measured colorimetric- 

 ally, using the method described by Mullin and 



37 



