Bering Sea
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The Bering (or Imarpik) Sea is a body of water in the Pacific Ocean that comprises a deep water basin (the Aleutian Basin) which rises through a narrow slope into the shallower water above the continental shelves. The Bering Sea is separated from the Gulf of Alaska by the Alaska Peninsula and Aleutian Islands. Covering over two million square kilometers (775,000 sq. miles), it is bordered on the east and northeast by Alaska, on the west by Russia's Siberia and Kamchatka Peninsula, on the south by the Alaska Peninsula and the Aleutian Islands and on the far north by the Bering Strait which separates the Bering Sea from the Arctic Ocean's Chukchi Sea. It is named for the first European discoverer to sail its waters, the Danish navigator Vitus Bering.
The Bering Sea ecosystem includes resources within the jurisdiction of the United States and Russia, as well as international waters in the ‘Donut Hole’. The interaction between currents, sea ice, and weather make for a vigorous and productive ecosystem.
The Bering Sea shelf break is the dominant driver of primary productivity in the Bering Sea .[1]. This zone, where the shallower continental shelf drops off into the Aleutian basin is also known as the “Greenbelt”. Nutrient upwelling from the cold waters of the Aleutian basin flowing up the slope and mixing with shallower waters of the shelf provide for constant production of phytoplankton.
The second driver of productivity in the Bering Sea is seasonal sea ice that, in part, triggers the spring phytoplankton bloom. Seasonal melting of sea ice causes an influx of lower salinity water into the middle and other shelf areas, causing stratification and hydrographic effects which influence productivity .[2]. In addition to the hydrographic and productivity influence of melting sea ice, the ice itself also provides an attachment substrate for the growth of algae as well as interstitial ice algae. The productivity associated with sea ice is under threat as global warming causes a reduction of sea ice in the Bering Sea.
Some evidence suggests that great changes to the Bering Sea ecosystem have already occurred. Warm water conditions in the summer of 1997 resulted in a massive bloom of low energy coccolithophorid phytoplankton (Stockwell et al. 2001). A long record of carbon isotopes, which is reflective of primary production trends of the Bering Sea, exists from historical samples of bowhead whale baleen [3]. Trends in carbon isotope ratios in whale baleen samples suggest that a 30-40% decline in average seasonal primary productivity has occurred over the last 50 years. [3]. The implication is that the carrying capacity of the Bering Sea is much lower now than it has been in the past.
Islands of the Bering Sea include:
- Pribilof Islands
- Komandorski Islands, including Bering Island
- St. Lawrence Island
- Diomede Islands
- King Island
- St. Matthew Island
- Karaginsky Island
The Bering Sea contains 16 submarine canyons including the largest submarine canyon in the world, Zhemchug canyon.
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[edit] Bering Sea Biodiversity
The Bering Sea is home to some of the world's most interesting wildlife. This sea supports many endangered whale species including bowhead whale, blue whale, fin whale, sei whale, humpback whale, sperm whale, and the rarest whale in the world, the Northern right whale. Other marine mammals include walrus, Steller's sea lion, Northern fur seal, beluga whales, killer whales (or orcas), and polar bears.
The Bering Sea is very important to the seabirds of the world. Over 30 species of seabirds and approximately 20 million individuals breed in the Bering Sea region. Seabird species include tufted puffins, the endangered short-tailed albatross, spectacled eider, and red-legged kittiwakes. Many of these species are unique to the area, which provides highly productive foraging habitat, particularly along the shelf edge and in other nutrient-rich upwelling regions, such as the Pribilof, Zhemchug, and Pervenets canyons.
Two Bering Sea species, the Steller's sea cow (Hydrodamalis gigas) and spectacled cormorant (Phalacrocorax perspicillatus), are extinct because of overexploitation by man. In addition, a small subspecies of Canada goose, the Bering Canada goose (Branta canadensis asiatica) is extinct due to overhunting and introduction of rats to their breeding islands.
The Bering Sea supports many species of fish. Some species of fish support large and valuable commercial fisheries. Commercial fish species include 6 species of Pacific salmon, walleye pollock, red king crab, Pacific cod, Pacific halibut, yellowfin sole, Pacific ocean perch and sablefish. Fish biodiversity is high, and at least 419 species of fish have been reported from the Bering Sea.
[edit] Bering Sea Fisheries
The Bering Sea is world renowned treasure for its enormously productive and profitable fisheries, such as king crab, Bristol Bay salmon, pollock and other groundfish. These fisheries rely on the productivity of the Bering Sea via a complicated and little understood food web. The continued existence of these fisheries requires an intact, healthy, and productive ecosystem.
Commercial fishing is big business in the Bering Sea. Some of the largest seafood companies in the world rely on the Bering Sea to produce fish and shellfish. On the U.S. side, commercial fisheries in the Bering Sea catch approximately $1 billion worth of seafood annually, while Russian Bering Sea fisheries are worth approximately $600 million annually.
[edit] Bering Sea History
During the most recent ice age, the sea level was thought to be low enough to allow humans and other animals to migrate from Asia to North America on foot across what is now the Bering Strait, located on the northern side of the sea. This is commonly referred to as the "Bering land bridge" and is believed by some scholars (in dispute by others) to be the first entry of humans into the Americas.
There is a small portion of the Kula Plate in the Bering Sea. The Kula Plate is an ancient tectonic plate that used to subduct under Alaska during the Triassic period.
[edit] Links to Bering Sea data
The Bering Sea supports some of the world's richest fisheries, and landings from Alaskan waters represents half the U.S. catch of fish and shellfish. Because of the changes going on in the Arctic, future evolution of the Bering Sea climate/ecosystem is more uncertain. This is a symmetric problem: climate change impacts ecosystems, and ecosystems serve as indicators for climate change. Track the current State of the Bering Sea with [1]near-realtime ecological and climatic indicators.
[edit] References
- ^ Springer, A.M., C.P. McRoy, and M.V. Flint. 1996. The Bering Sea green belt: shelf-edge processes and ecosystem production. Fisheries Oceanography 5, 205-223.
- ^ Schumacher, J.D., T. J. Kinder, D. J. Pashinski, and R. L. Charnell. 1979. A structural front over the continental shelf of the eastern Bering Sea. Journal Physical Oceanography 9: 79-87.
- ^ a b Schell, D. M. 2000. Declining carrying capacity in the Bering Sea: isotopic evidence from whale baleen. Limnol. Oceanogr. 45(2): 459-462.
[edit] See also
[edit] External links
- Bering Sea Climate and Ecosystem Comprehensive resource on the physical and biological factors affecting life in the Bering Sea, with maps, photos, essays on key Bering Sea issues, organizations, ecosystem information, and viewable data with narratives on trends and ecosystem relevance.
- North Pacific Ocean theme page
