On the oceanic communication between the Western Subarctic Gyre and the deep Bering Sea

In the central and western subarctic Pacific, zooplankton biomass and chlorophyll concentrations during the mid 1960s to mid 1970s were a few times higher than in the preceding and following decades, corresponding to higher values of the atmospheric Northern Hemisphere Zonal Index (NHZI). In the Alaskan Gyre, however, it was reported that biomass of zooplankton and nekton doubled after the atmospheric regime shift in the mid 1970s. In the subtropical North Pacific, chlorophyll a concentration decreased drastically after 1980, although a decrease of zooplankton biomass was clearly seen only in the northern part of the subtropical gyre. Chlorophyll concentration in the central subarctic Pacific and zooplankton biomass in the Oyashio have been decreasing since the early 1980s. Additionally, chlorophyll concentration in the western subarctic Pacific and eastern Bering Sea, and zooplankton biomass in the central subarctic Pacific and eastern Bering Sea have also been decreasing since the late 1980s. In these regime‐shift situations, there is a general tendency for intensification of wind speed or de‐stratification to cause plankton biomass to decrease in regions where the upper mixed layer is deep, such as the western subarctic and north‐western subtropical water, whereas in relatively stratified areas, such as in the eastern subarctic and south‐western subtropical water, the effect is an increase of plankton biomass.

Subarctic climate

North Pacific High

10.1046/j.1365-2419.1998.00070.x

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Citations (73)

Hydrographic structure and transport of the Oyashio south of Hokkaido and the formation of North Pacific Intermediate Water

Journal of Geophysical Research Atmospheres (2001)

Ichiro Yasuda Yutaka Hiroe Kosei Komatsu Kiyoshi Kawasaki Terrence M. Joyce

Hydrographic structure and transport of the Oyashio south of Hokkaido were described with conductivity‐temperature‐depth and lowered acoustic Doppler current profiler (LADCP) survey performed in June 1998. The southwestward Oyashio transport just off the Hokkaido coast was 10.1 Sv in the density of 26.6–27.5σ θ , in which 2.5 Sv was from the Okhotsk Sea and 7.6 Sv was from the Western Subarctic Gyre (WSAG). The Oyashio northeastward countercurrent was 4.9 Sv. The cross‐gyre Oyashio transport in the area from the east coast of Hokkaido to the Subarctic Front was estimated to be 5.2 Sv; 2.4 Sv in 26.6–27.0σ θ was mainly composed of low potential vorticity Okhotsk Sea water and 2.8 Sv in 27.0–27.5σ θ mostly from WSAG, suggesting that the Okhotsk Sea water (WSAG water) would contribute to the formation of the upper (lower) part of the North Pacific Intermediate Water (NPIW). The Oyashio water was lower in oxygen than in the subtropical areas south of the Subarctic Front in the density of 26.9–27.6σ θ , possibly because of the absence of the Antarctic Intermediate Water (AAIW) influence with the relatively high oxygen water that might be transported along the western boundary of the North Pacific Ocean and along the Kuroshio Extension, increasing the oxygen in the areas south of the Subarctic Front. Just south of the Subarctic Front, a cold‐ and fresh‐core anticyclonic eddy was observed with a salinity minimum in the core, suggesting one possible formation process of NPIW. The density of the potential vorticity minimum in the southwestward Oyashio near Hokkaido was at around 26.65σ θ , which was lower than 26.8–26.9σ θ observed in the early 1990s. This is possibly because the potential vorticity vertical profiles in the Okhotsk Sea and WSAG significantly changed corresponding to the water mass regime shift occurred in the Subarctic Pacific in the mid‐1990s [ Kawasaki , 1999].

Subarctic climate

Hydrographic survey

Antarctic Intermediate Water

Circumpolar deep water

10.1029/1999jc000154

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Citations (68)

Tub toys orbit the Pacific subarctic gyre

Eos (2007)

Curtis C. Ebbesmeyer W. James Ingraham Thomas C. Royer C. E. Grosch

In 1992, a cargo container of children's bath toys fell overboard in the middle North Pacific Ocean. Subsequently, 29,000 toys were tracked 4,000 kilometers to southeastern Alaska [ Ebbesmeyer and Ingraham , 1994]. The spill's upcoming fifteenth anniversary has prompted an examination of the reports of toys stranded on shorelines around the Subarctic Gyre, a planetary vortex the size of the United States. Previous articles have reported the drift of sneakers and toys for a year or so only along the southern edge of the Pacific Subarctic Gyre [ Ebbesmeyer and Ingraham , 1992, 1994]. However, continuing reports of stranded toys have stimulated curiosity about how long it would take the currents that link the Gyre's perimeter between Asia and America to transfer flotsam around the Gyre, that is, its orbital period. These currents (Figure 1) are the North Pacific Drift Current, Alaska Current/ Alaska Coastal Current, Alaskan Stream, Bering Slope Current and East Kamchatka Current, Oyashio Current, and Kuroshio. In the Bering Sea, the North Aleutian Current recurves north from Attu Island eastward along the north side of the Aleutians to merge with the Bering Slope Current.

Subarctic climate

Drift current

Gulf Stream

10.1029/2007eo010001

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Citations (37)

Comparison of factors controlling phytoplankton productivity in the NE and NW subarctic Pacific gyres

Progress In Oceanography (1999)

Paul J. Harrison Philip W. Boyd Diana E. Varela Shigenobu Takeda Akihiro Shiomoto

Subarctic climate

10.1016/s0079-6611(99)00015-4

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