the Bering Shelf area southwest of St. Lawrence Island 

 (Stations 6-43). After investigation of Anadyr Strait, the 

 expedition proceeded north into the Chukchi Sea 

 (Stations 44-75). After completing the studies in the Chukchi 

 Sea, Bering Strait was surveyed twice (Stations 76-86). 

 Proceeding south from the Bering Strait, studies were undertaken 

 in the Chirikov basin (Stations 87-107) and the southern 

 Bering Sea (Stations 108-1 13). including the South Polygon. 



Materials and Methods 



Phytoplankton biomass was assessed at each station in the 

 Bering and Chukchi Seas as chlorophyll a fluorescence ( Parsons 

 etai, 1984). 



Briefly, water samples (250 ml) were collected at 11 

 depths from each station using Niskin bottles attached to a 

 rosette sampling apparatus. Samples were filtered through 

 25 mm Gelman glass fiber filters (pore size: 0.3 \im) in a 

 multiple-sample filtration apparatus using a vacuum pump. 

 Each filter was suctioned dry and then placed in a 20-ml glass 

 test tube with 1 ml of 90% acetone to extract the photosy nthetic 

 pigments. To facilitate extraction of all pigments, a tissue 

 grinder was used to homogenize the filter in acetone. The 

 sample was then transferred to a 15-ml centrifuge tube and 

 centrifuged for 10 min. After centrifugation, the supernatant 

 was transferred to a cuvette, where its fluorescence was measured 

 using a Turner Designs fluorometer before and after acidification 

 with two drops of 5% HCl. 



For analysis, chlorophyll data from stations on the shelf 

 south of St. Lawrence Island, in the Gulf of Anadyr, and in the 

 polygon stations were integrated from the surface to 50 m to 

 give areal chlorophyll values. In the Chirikov basin and 

 Chukchi Sea where the bottom is less than 50 m deep, chlorophyll 

 values were integrated from surface to bottom. 



Results 



Chlorophyll concentrations were measured at each of the 

 113 stations studied during the cruise from 27 July to 



2 September 1988. Samples for chlorophyll analysis were 

 obtained at approximately 10 discrete depths at each station. 

 Over 1,000 samples were collected and analyzed in this 

 comprehensive study of the Bering and Chukchi Seas. 



Central Bering Sea Polygons 



The East and South Polygons each consist of five stations 

 in the deep Bering Sea. The polygon stations are part of a 

 continuing study and were included in the Second Joint LTS- 

 USSR Bering Sea Expedition in 1984. 



East Polygon. Stations 1 to 5 were located in the East 

 Polygon ( 58°N, 1 75° W) over the shelf slope area in the eastern 

 Bering Sea (Frontispiece). Bottom depth at these stations 

 ranged from 140 m at Station 5 to 3,190 m at Station 3. 

 Integrated chlorophyll values ranged from 22 mg/m- at Station 

 5 to 121 mg/m- at Station 2. The average for all stations was 

 66 mg/m-. Deep-water (2,689 m and 3,190 m) Stations 2 and 



3 had the highest values, 1 2 1 and 90 mg/m-, respectively, with 



the lowest values 22 and 48 mg/m-, being found at the shallower 

 ( 140 m and 150 m) shelf-slope Stations 5 and 4, respectively. 

 South Polygon. Stations 108 to 1 13 were located in the 

 South Polygon (53°N, 175°W) in the deep basin of the Bering 

 Sea over Bowers Ridge ( Frontispiece). The minimum depth at 

 these stations is 220 m. Integrated chlorophyll values were less 

 than 30 mg/m- at each station with the exception of Station 1 1 2 

 (67 mg/m-). The average for all stations was 35 mg/m-. 



Gulf of Anadyr and Western Bering Shelf 



Stations 7 to 43 were located in the Gulf of Anadyr and on 

 the adjacent shelf southwest of St. Lawrence Island 

 (Frontispiece). Integrated chlorophyll ranged from 13 mg/nr 

 at Station 1 2, east of Cape Navarin outside the Gulf of Anadyr, 

 to 797 mg/m- at Station 24 in the central region of the gulf 

 (Fig. 1). Relatively low values (13 to 45 mg/m-) characterized 

 the southern half of the study area, particularly the shelf area 

 south of St. Lawrence Island. High values were measured near 

 the northern coast of the Gulf of Anadyr. Stations 24 and 26 had 

 exceptionally high concentrations of 797 mg/m- and 

 430 mg/m-, respectively. These were some of the highest 

 values measured during the cruise. Station 26 had chlorophyll 

 concentrations greater than 50.0 mg/m' in the top 10 meters, 

 decreasing to less than 1.0 mg/m' below 20 meters (Fig. 2b). 



Fig. 1 . Depth integrated ((l-?0 m) chlorophyll (mg chl ii/nr ) lor Akademik 

 Korolev stations. 



The highest chlorophyll values were found in the north and 

 central Gulf of Anadyr with concentrations decreasing to the 

 south and east (Fig. 1 ). A cross section, from Station 26 in the 

 northwest comer of the gulf to Station 35 on the adjacent shelf 

 area south of Anadyr Strait, shows a subsurtace chlorophyll 

 maximum (>15.0 mg/m') located along the northern coast of 



124 



