analysis of suspended sediment concentration. 

 A total of 62 transmissometer lowerings were 

 accomplished and 142 water samples were col- 

 lected. 



During the Noi'ton Sound operations on 21 

 July, four stations were occupied. At each sta- 

 tion a Nansen bottle cast was made to obtain 

 water samples at 5 meter intervals from the 



surface to near the bottom, current speed and 

 direction were measured at 5-meter intervals 

 to near the bottom, a gravity core sample was 

 obtained, a Van Veen grab sample was obtained, 

 and a transmissometer lowering was accom- 

 plished. These data and samples are retained 

 by the Department of Oceanography, Univer- 

 sity of Washington. 



Water Masses 



Hydrographic conditions in the northern Ber- 

 ing Sea and Bering Strait in July 1968 closely 

 paralleled the summer regime observed in pre- 

 vious surveys, showing a relatively warm 

 (>5°C), low salinity (<32.5%o) water mass in 

 the upper 10 meters and a layer of gradients 

 between 10 and 15 meters overlying a colder 

 (<3°C), more saline (>32.5%o) water mass 

 (figs. 3-14). Large zonal gradients of tempera- 

 ture and salinity were observed at the surface 

 in the eastern portion of the survey area (figs. 

 15 and 16). The warm (>7.0°C), low salinity 

 (<31.0%o) water mass which extended along 

 the Alaskan coast in the surface layer corre- 

 sponded closely with the Alaskan Coastal Water 

 (8-10 X, 20-30%o) first defined by Saur, et al. 

 (1954). The low salinity of this water mass is 

 attributed to dilution by the effluents of the 

 Yukon and Kuskokwim rivers. The isolated par- 

 cel of warm, low salinity water found at the 

 surface northwest of St. Lawrence Island (figs. 

 15 and 16) may be the result of the advection 

 of some river runoff through the Strait of 

 Anadyr, possibly from the Anadyr River to 

 the southwest. 



The distribution of properties at 20 meters 

 revealed two distinct deeper water masses (figs. 

 17 and 18). One, in the western half of the sur- 

 vey area, was characterized by a temperature 

 range of 1.0 to 3.0 °C and a salinity greater 

 than 33.0%o. This mass was definitely the Modi- 

 fied Shelf Water (1.0 to 4.0°C, 32.6 to 33.0%o) 

 described by Saur, et al. (1954) which usually 

 has been found over the bottom in the northern 

 Bering Sea in the late summer. The second 

 water mass was found close to the northern 

 coa.st of St. Lawrence Island and was charac- 

 terized by temperatures less than 1.0 C and 

 salinities between 32.7 and 32.8%o (figs. 17 and 

 18). This water mass is the Deep Shelf Water, 



RESULTS 



described by Saur, et al. (1954) and Barnes 

 and Thompson (1938) which attains its low 

 temperatures from ice formation in the winter. 

 The source of this water mass has been hypo- 

 thesized to be the Gulf of Anadyr. The north- 

 eastward flow of water in the Strait of Anadyr 

 observed in July 1968 would tend to confirm 

 this hypothesis. Goodman, et al. (1942) re- 

 ported an eddy of this water mass in the sum- 

 mers of 1937 and 1938 between St. Lawrence 

 Island and St. Matthew Island with a tempera- 

 ture in the bottom water of -1.6°C. They sug- 

 gested this water was a remnant of winter 

 conditions when ice formation was occurring. 



Currents 



The current meter data were analyzed in an 

 unpublished research paper (Grider, 1969) at 

 the University of Washington. The direct meas- 

 usements of currents on station were resolved 

 into north and east components, which were 

 averaged over two depth layers. The upper 

 layer contained the average of all measured 

 currents between the surface and the 10 meter 

 depth ; the lower layer averaged all measure- 

 ments from 15 meters and deeper. The choice 

 of those layers was based on the fact that the 

 pycnocline in the northern Bering Sea is nor- 

 mally located between 10 and 15 meters in 

 the summer. 



Results of observations at the three time- 

 series current stations revealed semi-diurnal 

 fluctuations in the current records which were 

 of a tidal nature with a 12.4 hour period. This 

 tidal species was then subtracted from the cur- 

 rent records obtained at stations 1 to 28 which 

 had obvious semi-diurnal oscillations. The cur- 

 rent records for stations 29 through 76 were 

 not corrected because there were no obvious 

 periodic fluctuations and the time difference 

 between the occupation of these stations and 

 the first time-series current station was too 



3 



