Strait of Anadyr west of St. Lawrence Island 

 to the Bering Strait then northward through 

 the Strait (66°33'N). This water mass had the 

 lowest temperatures (0.0 to -1.7 °C) and high- 

 est salinities (32.4-32.9%o) in the entire survey 

 area. The oxygen content of this water mass 

 ranged from 8.0 to 9.0 ml/1, which was near or 

 greater than the saturation value for these 

 temperatures. A water mass having similar 

 characteristics was labeled as Deep Shelf Water 

 (DSW) by Saur, et al. (1954). This DSW 

 showed an increase in temperature, but a rela- 

 tively constant salinity as it was traced to the 

 north. DSW rarely has been reported (Grider, 

 1968) as far north as the Bering Strait in the 

 summer. 



The origin of the DSW remains unclear. 

 Grider (unpublished, 1968) stated that this 

 cold, saline water seemed to concentrate near 

 the eastern and western ends of St. Lawrence 

 Island in July 1968 and that this should give 

 some clues to its origin. Saur, et al. (1954), 

 said this water originated from freezing of sea- 

 water on the Bering Sea Shelf in the winter. 

 The distribution of properties near the bottom 

 in June 1969, with the coldest temperatures in 

 the Strait of Anadyr, suggest the Gulf of 

 Anadyr, or the central Bering Sea as possible 

 source regions. No direct measurements of cur- 

 rent were made to substantiate the inferred 

 direction of flow; however, the CGC NORTH- 

 WIND was observed to drift nearly 1.5 miles 

 to the northeast in approximately one hour 

 while occupying station 2 west of St. Lawrence 

 Island. The fact that the DSW could be traced 

 as far north as the Bering Strait suggests that 

 there may have been a northward flow in the 

 western channel of the Bering Strait in June 

 1969. 



A zone of transition of mixing was observed 

 between the Alaskan Coastal Water and the 

 Modified Shelf Water in all the cross sections 

 in the eastern portion of the survey area. This 

 transitional zone corresponds to the water mass 

 labeled Intermediate Water (2-4°C, 31.5- 

 31.9%o) by Saur, et al. (1954). Beyond section 

 C-C, this zone was characterized by a nearly 

 homogenous vertical distribution of properties 

 (figs. 23-37). 



DISTRIBUTION OF INORGANIC NUTRIENTS 



The distribution of nutrients showed great 



spatial variation. Nitrate was entirely absent 

 or present in low concentrations (<1.6 /xg-at/1) 

 in the surface waters of the eastern portion of 

 the survey area; however, concentrations in- 

 creased towards the western side of the area 

 with the highest values (12-16 ^ig-at/1) found 

 along the Siberian coast (figs. 12, 17, 22, 27, 

 32, and 37). Nitrite was absent or in very low 

 concentrations at all depths throughout the 

 entire area of study. Surface concentrations of 

 inorganic phosphate increased from less than 

 0.8 /i.g-at/1 on the eastern side of the area to 

 maximum values of 1.6 /xg-at/1 near the Si- 

 berian coast (figs. 11, 16, 21, 26, 31, and 36). 



The horizontal gradients of inorganic nu- 

 trients at subsurface levels were similar to 

 those at the sea surface, but higher concentra- 

 tions were involved. The highest values of phos- 

 phate (>2.0 /Ltg-at/1) and nitrate (>18.0 /xg- 

 at/1) occurred in the Deep Shelf Water on the 

 western side of the survey area (figs. 11, 12, 

 21, 22, 26, 27, 31, and 32). There was a decrease 

 in both phosphate and nitrate values northward 

 in the Deep Shelf Water, indicating flow to the 

 north. The high inorganic nutrient concentra- 

 tions in the DSW could be used to determine 

 the source of this cold water. The distinct strati- 

 fication of the water in the northern Bering 

 Sea and Bering Strait indicated by the tem- 

 perature and salinity distributions was dupli- 

 cated by the distribution of nitrate and phos- 

 phate. The large gradients of the nutrient 

 concentrations corresponded with similar gra- 

 dients of temperature and salinity suggesting 

 the possibility that these inorganic nutrients 

 may be considered as quasi-conservative prop- 

 erties in this limited area of investigation. 



The source of the high nutrient concentra- 

 tions in the western portion of the Bering Sea 

 and Bering Strait has not been determined. 

 Barnes and Thompson (1938) suggested the 

 Gulf of Anadyr as a source. Coachman and 

 Aagaard (1966) have stated that the distribu- 

 tion of properties in the northern Bering Sea 

 and Bering Strait is probably determined by 

 advection into the area. Our data do not solve 

 the problem, but the nutrient distributions 

 found in 1969 do suggest that the Gulf of Ana- 

 dyr is the source of the high concentrations. 

 The Anadyr River has a mean annual dis- 

 charge of 1660 mVsec (Sokolov, 1964) into the 

 Gulf, and there are several smaller streams in 



3 



