Oceanograpliic Investigation of the 

 Northern Bering Sea and Bering Strait 



8-21 June 1969 



David M. Hushv ' and Gary L. Hufford - 



INTRODUCTION 



The U.S. Coast Guard Oceanographic Unit 

 has been conducting investigations of summer 

 conditions in the Bering Sea-Bering Strait- 

 Chukchi Sea area since 1967. Results of the 

 1967 and 1968 investigations have been pub- 

 lished as part of the Coast Guard Oceano- 

 graphic Report series (Husby. 1969 ; and Husby, 

 in preparation). This report contains the ocean- 

 ographic results obtained in this area on the 

 cruise of the USCGC NORTHWIND (WAGB- 

 282) during 8-21 June 1969. The main purpose 

 of this investigation was to provide information 

 on the summer circulation and the interaction 

 of the water masses in the northern Bering Sea. 

 The Institute of Marine Science of the Univer- 

 sity of Alaska participated in the cruise with a 

 secondary purpose to investigate the physical 

 and chemical parameters governing the biologi- 

 cal productivity of the Bering Sea. 



The importance of the flow through the Ber- 

 ing Strait to the hydrography of the Arctic 

 Ocean has been described by Coachman and 

 Barnes (1961) and Gushchenkov (1964). The 

 relatively warm Bering Sea water flows north- 

 ward through the Bering Strait, mixes with the 

 colder Siberian Shelf water in the Chukchi Sea, 

 and then intrudes into the Arctic Ocean at sub- 

 surface levels in the Beaufort Sea gyral. In 

 summer the Bering Sea water which flows into 

 the Arctic Ocean is probably the main compo- 



' U.S. Coast Guard Oceanographic Unit. Present ad- 

 dress: Department of Oceanography, University of 

 Washington, Seattle, Washington 98105. 



2 U.S. Coast Guard Oceanographic Unit, Bldg. 159-E. 

 Washington Navy Yard, Washington, D.C. 20390. 



nent of the temperature maximum layer at 

 75-100 meters in the western basin of the 

 Arctic. 



METHODS 



In investigation of the general physical and 

 chemical oceanography of the northern Bering 

 Sea was conducted during 8-21 June 1969 by 

 personnel from the U.S. Coast Guard Oceano- 

 graphic Unit. A total of 73 oceanographic sta- 

 tions were occupied in water depths which 

 rarely exceeded 50 meters (fig. 1). At each 

 station a Nansen bottle cast was made to obtain 

 measurements of temperature, salinity, and 

 the concentrations of dissolved oxygen and in- 

 organic nutrients. Observations were made at 

 5-meter intervals from the surface to near 

 bottom on each cast. 



Water temperature was measured at each 

 level by a pair of deepsea reversing thermom- 

 eters. Corrected temperatures from the pair of 

 thermometers were averaged when the differ- 

 ence between them was less than 0.05C°. The 

 resulting in situ temperatures are considered 

 accurate to within ±0.025C°. 



Water samples were drawn from each Teflon- 

 lined Nansen bottle and determinations of sa- 

 linity were made aboard the ship using a 

 Bissett-Berman Model 6220 inductive salinom- 

 eter. Replicate determinations were made on 

 each sample and the resulting salinities are 

 believed to have a laboratory accuracy of 

 it.005%o. The conductivity values obtained were 

 converted to salinity by use of the International 

 Oceanographic Tables published jointly by 

 UNESCO and the National Institute of Ocean- 

 ography of Great Britain (UNESCO, 1966). 



