euphotic zone. High phytoplankton biomass at Stations 24 and 

 26 with lower biomass at surrounding stations indicate that 

 there may be a more complex production system operating in 

 the Gulf of Anadyr than our sampling regime was able to 

 adequately evaluate. 



Chlorophyll data indicate that the tlow of Anadyr water as 

 the Anadyr Stream is entrained along the Soviet coast as it 

 flows north. High chlorophyll measurements consistently 

 occur near the Soviet coastline in the northern Bering Sea. 

 However, the influence of the Anadyr Stream on phytoplankton 

 biomass further from the coast was evident in a large loop of 

 chlorophyll isoplelhs in the central Chirikov basin (Fig. 1). 

 This pattern of phytoplankton distribution could result from the 

 flow of Anadyr water through the western end of Shpanberg 

 Strait into Chirikov basin or it could result from eastward 

 advection of high nutrient water flowing through Anadyr 

 Strait. Analysis of cross-sections from Chirikov basin indicate 

 that the loop of phytoplankton biomass, shown as a distinct 

 subsurface chlorophyll maximum, may be a separate entity 

 from the phytoplankton stock closer to the Soviet coast 

 ( Fig. 2d ). Both phytoplankton concentrations merge as Anadyr 

 and Bering Shelf waters merge and flow through the western 

 side of Bering Strait. The highest phytoplankton biomass in the 

 Chirikov basin can be found near the Soviet coast. Future 

 expeditions should examine the Soviet coastal areas more 

 intensely. 



Water masses in the Chirikov basin (Anadyr, Bering 

 Shelf, and Alaska Coastal) appeared well-defined with respect 

 to phytoplankton biomass distribution. An explanation for the 

 "loop" of phytoplankton in the central Chirikov basin is difficult 

 from chlorophyll data alone. The flow of Anadyr and Bering 

 Shelf water into the Chukchi Sea carries not only nutrients but 

 phytoplankton from the productive regions upstream in the 

 Chirikov basin. As opposed to the areas south of Bering Strait, 

 identification of individual water masses by chlorophyll 

 distribution is difficult. The absence of high chlorophyll values 



near the Alaskan coast reflects the passage of nutrient-poor 

 Alaska Coastal water. The high nutrient Anadyr and Bering 

 Shelf water masses and their associated phytoplankton stocks 

 mix in Bering Strait and flow into the Chukchi Sea creating the 

 large chlorophyll pool in the center of the basin (Fig. I ). 



Chlorophyll distribution in the Chukchi Sea supports the 

 presence of a southeast flowing current, from the north on the 

 Soviet coast (Zenkevitch, 1963; Coachman & Shigaev, 

 Subchapter 2.1, this volume). Areal distribution and depth- 

 sections of data indicate that the high chlorophyll values found 

 in this region have a distinct source near the Soviet coast 

 (Figs. l,3c-e). Depth-sections from the northernmost (Stations 

 59-65 and 44-50) transects suggest the existence of two 

 separate chlorophyll stocks, one over Hope Sea Valley in the 

 central Chukchi basin and one along the Soviet coast northeast 

 of Kolyuchin Bay (Figs. 3d,e). Data from the southernmost 

 transects in the Chukchi Sea, below 67° latitude, do not clearly 

 show these stocks (Fig. 3b). It is difficult to distinguish the 

 potential influence of high nutrient Siberian Coastal water 

 from that of Anadyr Stream flowing north through Bering 

 Strait. 



The data from the Akculewik Korolev expedition fill several 

 gaps in the growing data base for the Bering/Chukchi Seas. 

 Since 1983, the ISHTAR Project has studied the ecology of the 

 northern Bering and southern Chukchi Shelf. But it was not 

 until the results of the expedition aboard XheAkadeinik Korolev 

 that hypotheses concerning the functioning of this productive 

 marine ecosystem could be confirmed (see Walsh et ciL, 1 989). 



This project was part of the Third Joint US-USSR Bering & 

 Chukchi Seas Expedition aboard the Soviet research vessel Akademik 

 Korolev. We express appreciation to the US Fish and Wildlife Service 

 and the USSR State Committee for Hydrometeorology . who made our 

 participation possible. Our participation was funded in part by the 

 National Science Foundation. Grant DPP-8405286. Contribution 

 No. 627. Institute of Marine Science. University of Alaska. Fairbanks, 

 AK 99775-1080, USA. 



5.1.3 Distributions of Algal Pigments in Near- 

 surface Waters 



ROBERT R. BIDIGARE, MICHAEL E. ONDRUSEK, and JAMES M. BROOKS 



Geochemicul and Environmental Research Group. Departmenl of Oceanography. Te.xas A&M Universitx. College Station. 

 Texas. USA 



Introduction 



The Bering Sea is a productive, high-latitude oceanic 

 environment whose expanse shelf supports large standing 

 stocks of zooplankton and marine vertebrates. In contrast to 

 most oceanic regions, the Bering Sea has high levels of 

 phytoplankton biomass and production associated with waters 



overlying its shelf domain, as well as its open-ocean domain 

 (Holmes, 1958; Kawamura, 1963; Taniguchi, 1969; McRoy 

 etai, 1972; Koike ('/«/., 1982; Sambrotto <>/«/., 1984, 1986; 

 Hansen et al., 1989). Wal.sh et al. (1985) proposed that a 

 significant proportion of the shelf-based production is 

 transported to the Bering Sea Slope, which serves as a major 

 storage site for atmospheric carbon dioxide. The fact that the 



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