Spring Bloom Colors the Pacific Near Hokkaido

, also known as Oya Siwo, Okhotsk or the Kurile current, is a cold

subarctic The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of humid continental regions and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, and the Cairngorms. Genera ...

ocean current An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth conto ...

that flows south and circulates counterclockwise in the western North

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...

. The waters of the Oyashio Current originate in the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

and flow southward via the

Bering Sea The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Am ...

, passing through the Bering Strait and transporting cold water from the Arctic Sea into the Pacific Ocean and the

Sea of Okhotsk The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...

. It collides with the

Kuroshio Current The , also known as the Black or or the is a north-flowing, warm ocean current on the west side of the North Pacific Ocean basin. It was named for the deep blue appearance of its waters. Similar to the Gulf Stream in the North Atlantic, the Ku ...

off the eastern shore of

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

to form the North Pacific Current (or Drift). The nutrient-rich Oyashio is named for its metaphorical role as the that provides for and nurtures marine organisms. The current has an important impact on the climate of the

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admin ...

, mainly in

Kamchatka The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and west ...

and Chukotka, where the northern limit of tree growth is moved south up to ten degrees compared with the latitude it can reach in inland

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part ...

. The waters of the Oyashio Current form probably the richest

fishery Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, ...

in the world owing to the extremely high-nutrient content of the cold water and the very high

tides Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables c ...

(up to ) in some areas – which further enhances the availability of nutrients. However, the Oyashio Current also causes

Vladivostok Vladivostok ( rus, Владивосто́к, a=Владивосток.ogg, p=vɫədʲɪvɐˈstok) is the largest city and the administrative center of Primorsky Krai, Russia. The city is located around the Golden Horn Bay on the Sea of Japan, ...

to be the most equatorward

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...

to seasonally freeze and require icebreaking ships to remain open in winter. Nonetheless, this has relatively little effect on the fish yield through the Sea of Okhotsk, because the large tides mean freezing does not occur so easily. During

glacial period A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

s, when lower

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

exposed the

Bering land bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of ...

, the current could not flow in the regions the Oyashio affects today. The level of cooling with the onset of glacial conditions (after an

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

) was much less than in other areas of the Earth at similar latitudes. This allowed Tōhoku and

Hokkaidō is Japan, Japan's Japanese archipelago, second largest island and comprises the largest and northernmost Prefectures of Japan, prefecture, making up its own List of regions of Japan, region. The Tsugaru Strait separates Hokkaidō from Honshu; th ...

– the only areas of

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea ...

with enough snowfall to potentially form glaciers – to remain unglaciated except at high elevations during periods when Europe and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

were largely glaciated. This lack of glaciation explains why, despite its present climate being much colder than most of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

, East Asia has retained 96 percent of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Ocean current An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth conto ...

* Oceanic gyres *

Physical oceanography Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters. Physical oceanography is one of several sub-domains into which oceanography is div ...

References

*Reddy, MPM (2001): ''Descriptive physical oceanography''. Taylor and Francis, , pp 367–8.

External links

Regional Definition page for the Oyashio Current
UNEP Global International Waters Assessment (GIWA), accessed 26 July 2018 {{Ocean Currents of the Pacific Ocean Bering Strait Temperate Northern Pacific