mass occupies the entire water column, and 

 then during spring and summer, a two-layered 

 structure is formed as a result of heating in 

 the surface layers and an influx of warmer 

 North Pacific water. 



Analyses of the temperature and salinitj' 

 distributions (figs. 3, 4, 10, 11, 17, 18, 24, 25, 

 31, and 32) from the 1970 survey revealed the 

 presence of the two-layered structure reported 

 in past investigations (Arsen'yev, 1967). The 

 surface layers were separated from the bottom 

 waters by a very strong seasonal thermocline. 



The surface waters of the Gulf of Anadyr 

 during 1970 can be separated into three types : 

 western surface water, eastern surface water, 

 and southeastern warm water (figs. 38-41). 

 Western surface water (0-lOm, west of 

 178°W) appears to be influenced to a con- 

 siderable extent by effluent from the Anadyr 

 River, showing surface salinities of less than 

 29.50nn (figs. 4, 39). Temperatures ranged 

 from less than 5.0 to 6.5°C (fig. 38). Efiluent 

 from the Anadyr River appears to flow south 

 towards Cape Navarin (fig. 39). 



Southeastern warm water was observed from 

 the surface to 10 meters in the southeastern 

 part of the Gulf of Anadyr (figs. 38-39, 3-4). 

 This water was characterized by relatively high 

 temperatures (>8°C) and relatively low .salin- 

 ities (<31.0f'i|„). The low salinity indicates 

 that the source of the intrusion may have been 

 a westward extension of the Alaskan Coa.stal 

 Water (Saur, et al., 1954), but more data are 

 needed to determine this with certainty. 



Eastern surface water (0 to 20 meters 

 depth) was characterized by a temperature and 

 salinity range of 7.0 to 7.4''C and 31.0 to 

 31.5%n, respectively (figs. 10-11, 17-18, 38- 

 39). 



The bottom waters of the two-layered struc- 

 ture in the Gulf of Anadyr can be separated 

 into three diflferent water masses : two cold 

 masses separated by a warmer one (fig. 44). 

 In the northwest section of the Gulf (figs. 

 31-32), a pocket of very cold (-1.0 to 

 -1.6'C), high salinity O34.0'!,',,,) water was 

 found near the mouth of Holy Cross Bay. Win- 

 ter freezing could produce this cold water mass, 

 but probably not in the Gulf because of the 

 relatively high salinity of the mass. Data from 

 the USCGC NORTHWIND taken in February 

 1968 (unpublished) in the Gulf of Anadyr 



showed temperatures and salinities of — 1.5 to 

 - 1.8° C and 32.2 to 33.4o/oo for the greater part 

 of the Gulf. Near Holy Cross Bay, salinities 

 to 34.2%o were observed. This deep bay (>100 

 meters) is characterized by a low freshwater 

 input and a shallow sill depth. These factors 

 along with evaporation could produce higher 

 salinity in the bay than in the Gulf. Winter 

 freezing would produce a cold high salinity 

 water mass isolated in the bay where it would 

 remain until enough was formed to spill over 

 the sill or until passed over the sill by seiching. 



The second mass of cold water was observed 

 in the southeastern section of the Gulf of Ana- 

 dyr (figs. 3-4). This water mass had a temper- 

 ature range the same as the cold water pocket 

 near Holy Cross Bay but with lower salinities 

 (32.2 to 32.5"|„,)- The low temperatures again 

 suggest winter formation, probably in the open 

 Gulf. 



A warmer (0 to 1.0°C), relatively saline 

 (32.5 to 33.0",,,,) bottom water mass was found 

 near the middle of the Gulf (figs. 44-45). This 

 water mass occupies the water column from 

 30 meters to bottom (fig. 10). Origin of the 

 mass has been sugge.sted to be an intrusion of 

 deeper water from the western Bering Sea 

 (Ratmanov, 1937). Arsen'yev (1967) has de- 

 scribed a current entering the Gulf of Anadyr 

 near Cape Navarin from the open sea with 

 the temperature and salinity characteristics of 

 2 to 7°C and 32.5 to 33%^. 



The water characteristics of three of the sta- 

 tions (7, 17, 21) that were reoccupied during 

 the cruise (32, 33, 31) were found to change 

 significantly (figs. 46-49), providing informa- 

 tion on the rate of change due to advection in 

 the region. At station 7, there was an increase 

 in temperature and .salinity from just below 

 the surface to the bottom (figs. 46, 47). This 

 was probably due to the penetration of the 

 warm .saline water from the western Bering 

 Sea flowing into the Gulf. At station 21 an 

 increa.se in temperature and a large decrease 

 in salinity was observed in the top 20 meters 

 of the water column after 3 days (figs. 48-49). 

 This change is probably due to effluent from the 

 Anadyr River with its low salinity mixing with 

 the surface waters. 



The water masses present in the Gulf of 

 Anadyr during the summer are aff'ected by 

 such factors as seasonal heating and cooling, 



