d) 



c) 



concentrations next to the islands on the western side indicating 

 that some of the phytoplankton associated with Bering Shelf- 

 Anadyr water flowed through the eastern portion of the strait. 



Chukchi Sea 



Stations 44 to 75 were in the southern Chukchi Sea 

 (Frontispiece). The highest values of integrated chlorophyll 

 (625, 696, and 1,167 mg/m-) found during the cruise were ^/ 



observed at stations 54, 56, and 55, respectively. Values in 

 excess of 300 mg chl/m- characterized the majority of these 

 stations with the highest values found in the center of the region 

 (Fig. 1). Thirteen of the 31 stations, all in the center of the 

 region or near the Soviet coast, had integrated chlorophyll 

 values greater than 300 mg/m-. Only the outer regions of the 

 study area to the north and east had values less than 1 00 mg/m-. 

 In the Chukchi, as with the Bering Sea components of the 

 cruise, high chlorophyll values were observed off the Soviet 

 coast at Stations 44. 59, 7 1 , and 72. The lowest values in the 

 area, less than 50 mg/m-, were found closer to the Alaskan 

 coast. Cross sections from Stations 72-75 and Stations 7 1-66 

 show high phytoplankton biomass on the western side of the 

 basin, presumably as a result of the flow of Bering Shelf- 

 Anadyr water carrying its load of phytoplankton and nutrients 

 (Figs. 3b,c). 



Cross sections from Stations 59-65, and Stations 44-50, 

 indicate that the characteristic water masses of this system are 

 no longer recognizable from chlorophyll distribution 

 measurements ( Figs. 3d,e). North ofapproximately 67° latitude, 

 the Bering Shelf-Anadyr water masses appear to spread out as 

 current speed decreases and the flow becomes bathymetrically 

 steered (Coachman & Shigaev, Subchapter 2.1, this volume). 

 High chlorophyll concentrations occurred all across the transect 

 even close to the Ala.skan coast at Station 48 (Fig. 3e). High 

 integrated chlorophyll (>,W0 mg/m- )ischaracteristic of Stations 

 54 and 64 near the eastern side of the study area ( Fig. I ). Cross 

 sections from the northern Chukchi Sea (Figs. 3d,e) exhibit a 

 pronounced subsurface chlorophyll maximum similar to those 

 observed in the Chirikov basin and Benng Strait. Concentrations 

 greater than 70.0 mg/m' were measured at 15 m at Station 54. b) 



Discussion and Conclusion 



Our data support the general model that the advection of 

 the Anadyr water mass over the continental shelf of the 

 northern Bering Sea and into the Chukchi Sea strongly influences 

 the biological regune. In its wake (Coachman et al.. 1975) is 

 left a bounty of biological production resulting from its nutrient 

 load and the morphology of the shelf. 



Chlorophyll measurements from the Gulf of Anadyr 3) 

 indicate a northward flow of nutrient-rich water around the 

 gulfs perimeter, originating from the bifurcation of the Bering 

 Slope Current in the vicinity of Cape Navarin. The influence 

 of Anadyr water (created by slight modification of Bering 

 Slope water in the Gulf of Anadyr) is not evident until it reaches 

 the euphotic zone as it flows around the Gulf of Anadyr and 

 through Anadyr Strait. The flrst biological indications of this 

 water mass are present at shallow-water stations in the northwest ^'g -"* 

 Gulf of Anadyr where the nutrient-rich water is exposed to the 



CL 

 UJ 

 Q 



STATIONS 

 44 45 46 47 48 49 50 



65 130 195 260 



59 60 61 62 63 64 65 



60 150 230 310 



71 70 69 68 67 66 





 10 

 20 

 30 

 40 

 50 

 60 



50 100 150 200 

 72 73 74 75 



25 50 75 100 130 

 76 77 78 ,— , n 79 80 81 







25 50 



DISTANCE (km) 



Vertical cross-sections of chlorophyll (mg/m') arranged from South 

 to North (a to e). Transect location given on Frontispiece. 



126 



