Dissolved oxygen content was determined by 

 a modified Winkler method using sodium thio- 

 sulfate as a standard and a starch indicator to 

 determine the titration endpoint. Water samples 

 were drawn from each Nansen bottle imme- 

 diately upon retrieval and treated with both 

 manganous sulfate and alkaline iodide. Repli- 

 cate determinations were made on each sample 

 and the oxygen values are believed accurate to 

 at least ±0.03 ml/1. 



Two samples were drawn from each Nansen 

 bottle in 125 ml polyethylene bottles and imme- 

 diately frozen in the ship's freezer. These 

 frozen samples were returned to the Coast 

 Guard Oceanographic Unit for determination of 

 concentrations of inorganic phosphate, nitrate, 

 and nitrite. The methods outlined in the manual 

 of Strickland and Parsons (1965) were used. 



Underwater photographs were taken at 25 

 stations using a Geodyne Model 205 bottom con- 

 tact camera for study of benthic organisms as 

 as well as indication of bottom currents. The 

 photographs were not compass-oriented, so no 

 quantitative information was obtained on bot- 

 tom currents. These photographs are retained 

 by the Coast Guard Oceanographic Unit and 

 will be the subject of a future report. 



Three scientists from the University of Alas- 

 ka Institute of Marine Science conducted inves- 

 tigations of primary productivity, organic 

 carbon, and trace metal distribution. A total 

 of 10 stations were taken in conjunction with 

 hydrographic stations, usually near 0800 hours 

 local time. At each station, approximately 30 

 liters of water were collected from four different 

 depths corresponding to measured light extinc- 

 tion levels. Water was drawn from each sample 

 to measure nitrate, total nitrogen, phosphate, 

 total phosphorus, silicate, and ammonia con- 

 centrations as well as plant pigments. Portions 

 of each sample were utilized to measure organic 

 carbon content and to perform carbon and nitro- 

 gen uptake experiments. At selected stations, 

 vertical tows for phytoplankton were conducted 

 from near bottom to the surface with a number 

 20-mesh nylon net. Water samples were ob- 

 tained at the same locations and depths as the 

 productivity stations for later analysis of trace 

 metal content. All these data are retained by 

 the University of Alaska, Institute of Marine 

 Science, and will be published in their report 

 series. 



DESCRIPTIO> OF WATER MASSES 



The distribution of water properties near the 

 surface in the northern Bering Sea and Bering 

 Strait in June 1969 was generally similar to 

 conditions observed in the past (Barnes and 

 Thompson, 1938; Goodman, et al., 1942; and 

 Saur, et al., 1954). Warm water (5-8°C) of low 

 salinity (<31.5%o) was found in the surface 

 layer along the Alaskan coast (figs. 2 and 5). 

 Water with these properties was first labeled 

 as Alaskan Coastal Water (ACW) by Saur, 

 et al. (1954), and is recognized by more recent 

 authors (Coachman and Aagaard, 1966). This 

 water mass had an oxygen content between 

 7.0-7.5 ml/1, which was near saturation. The 

 warm, low salinity water seen at stations 20-27 

 in the northwestern portion of Norton Sound 

 was probably the result of runoff of the Yukon 

 River (figs. 13 and 14). The low salinity surface 

 water of the entire region reflects the large 

 fresh-water discharge of the Alaskan and Si- 

 berian Rivers. The most important rivers are 

 the Yukon in Alaska, which has a mean annual 

 discharge of 6220 mVsec, and the Anadyr River 

 in Siberia which has a mean annual discharge 

 of 1660 mVsec (Sokolov, 1964). 



A relatively cold, low salinity surface water 

 mass (1.0 to 2.5°C, 31.4 to 32.3%o) with an 

 oxygen content of 9.0 to 10.0 ml/1, found on the 

 western side of the survey area has not been 

 classified previously (figs. 8-10, 13-15, 18-20, 

 23-25, 28-30, and 33-35). This water may have 

 been advected through the Strait of Anadyr to 

 the north, but its relatively high salinity pre- 

 cludes runoff from the Anadyr River as a major 

 component. 



In the western portion of the area of investi- 

 gation, a cold (0.5-2.0°C), highly oxygenated 

 (8.0-9.5 ml/1), saline water mass (31.9-32.5%o) 

 was found which corresponded closely with the 

 Modified Shelf Water (MSW) described by Saur, 

 et al. (1954). This MSW was found in 1969 

 along the east and west coast of St. Lawrence 

 Island in sections A-A' and B-B', then near 

 the bottom in the middle of section C-C and 

 from the surface to near the bottom in the 

 western portions of sections D-D', E-E', and 

 F-F' (figs. 8-10, 13-15, 18-20, 23-25, 28-30, 

 and 33-35. 



Near the bottom of the western portion of 

 the survey area (figs. 4 and 7), a water mass 

 seemed to intrude northeastward from the 



