Gulf of Alaska

The Gulf of Alaska (French: Golfe d'Alaska) is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, where Glacier Bay and the Inside Passage are found.

The Gulf shoreline is a rugged combination of forest, mountain and a number of tidewater glaciers. Alaska's largest glaciers, the Malaspina Glacier and Bering Glacier, spill out onto the coastal line along the Gulf of Alaska. The coast is heavily indented with Cook Inlet and Prince William Sound, the two largest connected bodies of water. It includes Yakutat Bay and Cross Sound. Lituya Bay (a fijord north of Cross Sound, and south of Mount Fairweather) is the site of the largest recorded tsunami in history. It serves as a sheltered anchorage for fishing boats.

Gulf of Alaska
Gulfofalaskamap
Gulf of Alaska
LocationSouth shore of Alaska
Coordinates57°N 144°W / 57°N 144°WCoordinates: 57°N 144°W / 57°N 144°W
TypeGulf
Native nameLand of the Frontier
Part ofNorth Pacific Ocean
River sourcesSusitna River
Basin countriesUnited States, Canada
IslandsKodiak Archipelago, Montague Island, Alexander Archipelago
SettlementsAnchorage, Juneau
GulfOfAlaska AMO 2008073
A view of the Gulf of Alaska from space. Notice the swirling sediment in the waters.

Ecology

The Gulf of Alaska is considered a Class I, productive ecosystem with more than 300 grams of carbon per square meter per year[1] based on SeaWiFS data.

Deep water corals can be found in the Gulf of Alaska. Primnoa pacifica has contributed to the location being labeled as Habitat Areas of Particular Concern.[2] P. pacifica is a deep water coral typically found between 150 metres (490 ft) and 900 metres (3,000 ft) here.[3]

Meteorology

The Gulf is a great generator of storms. In addition to dumping vast quantities of snow and ice on southern Alaska, resulting in some of the largest concentrations south of the Arctic Circle, many of the storms move south along the coasts of British Columbia, Washington, Oregon, and as far south as Southern California (primarily during El Niño events).[4] Much of the seasonal rainfall and snowfall in the Pacific Northwest and Southwestern United States comes from the Gulf of Alaska.

Extent

The International Hydrographic Organization defines the limits of the Gulf of Alaska as follows:[5]

On the North. The coast of Alaska.

On the South. A line drawn from Cape Spencer, the Northern limit of the Coastal Waters of Southeast Alaska and British Columbia to Kabuch Point, the Southeast limit of the Bering Sea, in such a way that all the adjacent islands are included in the Gulf of Alaska.

The US Geological Survey's Geographic Names Information System database defines the Gulf of Alaska as bounded on the north by the coast of Alaska and on the south by a line running from the south end of Kodiak Island on the west to Dixon Entrance on the east.[6]

Islands

References

  1. ^ Hogan, C. Michael (2011). "Gulf of Alaska. Topic ed. P.Saundry. Ed.-in-chief C.J.Cleveland. Encyclopedia of Earth". National Council for Science and the Environment. Retrieved June 13, 2013.
  2. ^ Stone Robert P; Shotwell S Kalei. (2007). "State of deep coral ecosystems in the Alaska Region: Gulf of Alaska, Bering Sea and the Aleutian Islands" (PDF). In: Lumsden SE et Al., Eds. The State of Deep Coral Ecosystems of the United States. NOAA Technical Memorandum CRCP-3. Silver Spring, MD: 65–108. Retrieved June 13, 2013.
  3. ^ Waller, RG; Stone, RP; Mondragon, J; Clark, CE (2011). "Reproduction of Red Tree Corals in the Southeastern Alaskan Fjords: Implications for Conservation and Population Turnover". In: Pollock NW, Ed. Diving for Science 2011. Proceedings of the American Academy of Underwater Sciences 30th Symposium. Dauphin Island, AL: AAUS; 2011. Retrieved June 13, 2013.
  4. ^ National Geospatial-intelligence Agency (2006). Prostar Sailing Directions 2006 Pacific Ocean and Southeast Ocean Planning Guides. Pub. (United States. National Geospatial-Intelligence Agency). Prostar Publications. p. 241. ISBN 978-1-57785-663-4. Retrieved November 26, 2018.
  5. ^ "Limits of Oceans and Seas, 3rd edition" (PDF). International Hydrographic Organization. 1953. Retrieved February 7, 2010.
  6. ^ U.S. Geological Survey Geographic Names Information System: Gulf of Alaska

External links

2018 Gulf of Alaska earthquake

On January 23, 2018, at 00:31 AKST, an earthquake occurred in the Gulf of Alaska near Kodiak Island. The earthquake, measured at 7.9 on the Mw scale, was approximately 280 kilometres (170 mi) southeast of Kodiak and happened at a depth of 25 kilometres (16 mi).It was initially measured as a M 8.2 event, but later downgraded by the United States Geological Survey. The earthquake was felt throughout most of southern Alaska, including the major cities of Anchorage and Fairbanks, and parts of neighboring British Columbia.The earthquake prompted tsunami warnings and advisories for Alaska, British Columbia, the U.S. West Coast, and Hawaii. Residents in low-lying areas along the Gulf of Alaska and in British Columbia were evacuated to shelters and higher ground. The Pacific Tsunami Warning Center later cancelled most of the alerts within four hours of the earthquake, due to the apparent lack of tsunami. The highest recorded waves after the event measured at under 8.3 inches (210 mm) above tide level on Kodiak Island.

Alaska Maritime National Wildlife Refuge

The Alaska Maritime National Wildlife Refuge (often shortened to Alaska Maritime or AMNWR) is a United States National Wildlife Refuge comprising 2,400 islands, headlands, rocks, islets, spires and reefs in Alaska, with a total area of 4.9 million acres (20,000 km2), of which 2.64 million acres (10,700 km2) is wilderness. The refuge stretches from Cape Lisburne on the Chukchi Sea to the tip of the Aleutian Islands in the west and Forrester Island in the southern Alaska Panhandle region in the east. The refuge has diverse landforms and terrains, including tundra, rainforest, cliffs, volcanoes, beaches, lakes, and streams.

Alaska Maritime National Wildlife Refuge is well known for its abundance of seabirds. About 75 percent of Alaskan native marine birds, 15 to 30 million among 55 species, use the refuge. AMNWR also provides a nesting habitat for an estimated 40 million seabirds, representing 80 percent of all seabirds in North America. The birds congregate in "bird cities" (colonies) along the coast. Each species has a specialized nesting site (rock ledge, crevice, boulder rubble, pinnacle, or burrow). Other animals present in this refuge include caribou, sea lions, bears, coyotes, seals, Canadian lynxes, beavers, foxes, muskrats, wolf packs, moose, walrus, river otters, marten, whales, Dall sheep and sea otters.

The administrative headquarters and visitor center are located in Homer, Alaska. In 1968, Simeonof National Wildlife Refuge, part of the Alaska Maritime National Wildlife Refuge, was designated as a National Natural Landmark by the National Park Service.

Aleutian Arc

The Aleutian Arc is a large volcanic arc in the U.S. state of Alaska. It consists of a number of active and dormant volcanoes that have formed as a result of subduction along the Aleutian Trench. Although taking its name from the Aleutian Islands, this term is a geologic grouping rather than a geographic one, and the Aleutian Arc extends through the Alaska Peninsula following the Aleutian Range to the Aleutian Islands.The Aleutian Arc reflects subduction of the Pacific Plate beneath the North American Plate. It extends 3,000 km (1,900 mi) from the Kamchatka Peninsula in the west to the Gulf of Alaska in the east. Unimak Pass at the southwestern end of the Alaska Peninsula marks the eastward transition from an intra-oceanic in the west to a continental arc in the east. Due to the arcuate geometry of the trench, the relative velocity vector changes from almost trench-normal in the Gulf of Alaska to almost trench-parallel in the west. Along the oceanic part of the subduction zone, convergence varies from 6.3 cm (2.5 in) per year to the north-northwest in the east to 7.4 cm (2.9 in) per year towards the northwest in the west.

Climate of Alaska

The climate of Alaska is determined by average temperatures and precipitation received statewide over many years. The extratropical storm track runs along the Aleutian Island chain, across the Alaska Peninsula, and along the coastal area of the Gulf of Alaska which exposes these parts of the state to a large majority of the storms crossing the North Pacific. The climate in Juneau and the southeast panhandle is a mid-latitude oceanic climate (similar to Scotland, or Haida Gwaii), (Köppen Cfb) in the southern sections and a subarctic oceanic climate (Köppen Cfc) in the northern parts. The climate in Southcentral Alaska is a subarctic climate (Köppen Dfc) due to its short, cool summers. The climate of the interior of Alaska is best described as extreme and is the best example of a true subarctic climate, as the highest and lowest recorded temperatures in Alaska have both occurred in the interior. The climate in the extreme north of Alaska is an Arctic climate (Köppen ET) with long, cold winters, and cool summers where snow is possible year-round.

Cross Sound

Cross Sound is a passage in the Alexander Archipelago in the southeastern region of the U.S. state of Alaska, located between Chichagof Island to its south and the mainland to its north. It is 48 km (30 mi) long and extends from the Gulf of Alaska to Icy Strait.

Cross Sound was named by James Cook in 1778 because he found it on May 3, designated on his calendar as Holy Cross day.The Cape Spencer Light marks the north side of the entrance to the sound from the Gulf of Alaska.

Dicks Arm is an inlet on northern Cross Sound.

Forrester Island Wilderness

Forrester Island Wilderness is a 2,832-acre (1,146 ha) wilderness area in the U.S. state of Alaska at Forrester Island (54°48′10″N 133°31′37″W). It was designated by the United States Congress in 1970. It is part of the Gulf of Alaska unit of the Alaska Maritime National Wildlife Refuge.

The island is located off the coast of the Alaska Panhandle, near its southernmost portion, west of Dall Island, in the Prince of Wales-Hyder Census Area. According to the Census Bureau the island has a land area of 3.97 sq mi (10.29 km2).

Haida Eddies

Haida Eddies are episodic, clockwise rotating ocean eddies that form during the winter off the west coast of British Columbia’s Haida Gwaii and Alaska’s Alexander Archipelago. These eddies are notable for their large size, persistence, and frequent recurrence. Rivers flowing off the North American continent supply the continental shelf in the Hecate Strait with warmer, fresher, and nutrient-enriched water. Haida eddies are formed every winter when this rapid outflow of water through the strait wraps around Cape St. James at the southern tip of Haida Gwaii, and meets with the cooler waters of the Alaska Current. This forms a series of plumes which can merge into large eddies that are shed into the northeast Pacific Ocean by late winter, and may persist for up to two years.Haida eddies can be more than 250 km in diameter, and transport a mass of coastal water approximately the volume of Lake Michigan over 1,000 km offshore into the lower nutrient waters of the northeast Pacific Ocean. These "warm-core rings" transport heat out to sea, supplying nutrients (particularly nitrate and iron) to nutrient depleted areas of lower productivity. Consequently, primary production in Haida eddies is up to three times higher than in ambient waters, supporting vast phytoplankton-based communities, as well as influencing zooplankton and icthyoplankton community compositions.The Haida name is derived from the Haida people native to the region, centered on the islands of Haida Gwaii (formerly known as the Queen Charlotte Islands).

Kodiak Archipelago

The Kodiak Archipelago is an archipelago, or group of islands, south of the main land mass of the state of Alaska (United States), about 405 km (252 mi) by air south of Anchorage in the Gulf of Alaska. The largest island in the archipelago is Kodiak Island, the second largest island in the United States. The archipelago is about 285 km (177 mi) long and 108 km (67 mi) across, from the Barren Islands on the north to Chirikof Island and the Semidi Islands group on the south. The Archipelago contains 13,890 km2 (5,360 sq mi) of land. The Kodiak Archipelago contains about 40 small glaciers, numerous streams and many species of land and marine animals. Much of its land is forested.

The Kodiak Island Borough contains all of the Kodiak Archipelago and some lands on the mainland. The Kodiak National Wildlife Refuge encompasses a large percentage of the land in the archipelago.

Kodiak–Bowie Seamount chain

The Kodiak–Bowie Seamount chain, also called the Pratt–Welker Seamount chain and the Kodiak Seamounts, is a seamount chain in southeastern Gulf of Alaska stretching from the Aleutian Trench in the north to Bowie Seamount, the youngest volcano in the chain, which lies 180 km (112 mi) west of the Queen Charlotte Islands, British Columbia, Canada. The oldest volcano in the chain is the Kodiak Seamount. Although the Kodiak Seamount is the oldest extant seamount in the Kodiak-Bowie chain, the adjacent lower slope contains transverse scars indicating earlier subduction of seamounts.

The Kodiak–Bowie Seamount chain are mostly extinct volcanoes that formed above the Bowie hotspot. This is a 100-to-150-km-wide morphological swell presumably of thickened hotspot generated crust, although there are no seismic refraction data across the swell to define crustal thickness. The crest of one such peak, Patton Seamount originally formed off Washington state as a submerged volcano 33 million years ago. Over time, as the Pacific Plate moved steadily northwest, Patton Seamount was carried off the Bowie hotspot and into the Gulf of Alaska. New volcanoes were formed one after another over the hotspot, creating the Kodiak–Bowie Seamount chain.

Explorations of the Kodiak–Bowie Seamount chain have shown that despite the fact that most of the seamounts were created by the Bowie hotspot, all are unique in their size, shape, and volcanic features. The seamounts teem with deep-sea corals, sponges, and fish. Recent expeditions to these seamounts using manned submersibles and ROVs have discovered many marine species and have greatly expanded the knowledge of the range of deep sea corals in this region. For example, the Bowie Seamount is a biologically rich area with a dynamic and productive ecosystem. Because of this unique biological rich area, Bowie Seamount was declared a Pilot Marine Protected Area on December 8, 1998.The Kodiak–Bowie seamount chain is at the northern triple junction between the Pacific, North American, and Juan de Fuca plates. Available age determinations on Kodiak and Giacomini Seamounts give an approximate average rate of movement along the chain of 6.5 cm (3 in) per year.

Mount Crillon

Mount Crillon is a high peak of the Fairweather Range, the southernmost part of the Saint Elias Mountains. It lies southeast of Mount Fairweather, in the promontory between the Gulf of Alaska and Glacier Bay. It is included in Glacier Bay National Park. The peak was named after Felix-Francois-Dorothee de Bretton, Comte de Crillon, by his friend, the French explorer Jean Francois de Galaup de la Perouse.

Mount Miller

Mount Miller is an isolated peak of the Saint Elias Mountains in Alaska, United States. It is notable for its position among spectacular icefields, its distance from any inhabited place, and its large rise above local terrain. It is over 65 miles (110 km) from McCarthy, the nearest habitation, and over 105 miles (170 km) away from Yakutat, the nearest significant town. Exemplifying the size of the mountain, the south flank rises 9000 feet (2743 m) above the Duktoth River valley to the south in approximately 9 horizontal miles (14.5 km).

Mount Miller is the high point of the east-west trending Barkley Ridge, located on the south side of the Bagley Icefield, one of the largest icefields in North America. The Bering Glacier flows from the Bagley Icefield at the western end of the ridge, while the southeast slopes of the ridge head the Yahtse Glacier. The only side of the ridge that is not completely glaciated is the south side, where the Robinson Mountains lie between Barkley Ridge and the Gulf of Alaska.

Since Mount Miller is so isolated, and is not of extraordinary absolute elevation by Alaskan standards, it was not climbed until very recently. The first ascent of the peak was made in 1996 by Charlie Sassara, Ruedi Homberger, Reto Ruesh, Paul Claus, and Carlos Buhler, via the West Ridge.

North American Arctic

The North American Arctic comprises the northern portions of Alaska (USA), Northern Canada and Greenland. Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean. The western limit is the Seward Peninsula and the Bering Strait. The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.

The Arctic region is defined by environmental limits where the average temperature for the warmest month (July) is below 10 °C (50 °F). The northernmost tree line roughly follows the isotherm at the boundary of this region. The area has tundra and polar vegetation.

North Pacific right whale

The North Pacific right whale (Eubalaena japonica) is a very large, thickset baleen whale species that is extremely rare and endangered.

The Northeast Pacific population, which summers in the southeastern Bering Sea and Gulf of Alaska, may have no more than 40 animals. A western population that summers near the Commander Islands, the coast of Kamchatka, along the Kuril Islands and in the Sea of Okhotsk is thought to number in the low hundreds. Before commercial whaling in the North Pacific (i.e. pre-1835) there were probably over 20,000 right whales in the region. The taking of right whales in commercial whaling has been prohibited by one or more international treaties since 1935. Nevertheless, between 1962 and 1968, illegal Soviet whaling killed at least 529 right whales in the Bering Sea and Gulf of Alaska as well as at least 132 right whales in the Sea Okhotsk. plus an additional 104 North Pacific right whales from unspecified areas.The International Union for Conservation of Nature categorizes the species as "Endangered", and categorizes the Northeast Pacific population as "Critically Endangered". The Center for Biological Diversity argues that the North Pacific right whale is the most endangered whale on Earth.

October 2009 North American storm complex

The October 2009 North American storm complex was a powerful extratropical cyclone that was associated with the remnants of Typhoon Melor, which brought extreme amounts of rainfall to California. The system started out as a weak area of low pressure (an Aleutian Low), that formed in the northern Gulf of Alaska on October 7. Late on October 11, the system quickly absorbed Melor's remnant moisture, which resulted in the system strengthening significantly offshore, before moving southeastward to impact the West Coast of the United States, beginning very early on October 13. Around the same time, an atmospheric river opened up (the Pineapple Express), channeling large amounts of moisture into the storm, resulting in heavy rainfall across California and other parts of the Western United States.

Pacific ocean perch

The Pacific ocean perch (Sebastes alutus), also known as the Pacific rockfish, Rose fish, Red bream or Red perch has a wide distribution in the North Pacific from southern California around the Pacific rim to northern Honshū, Japan, including the Bering Sea. The species appears to be most abundant in northern British Columbia, the Gulf of Alaska, and the Aleutian Islands (Allen and Smith 1988).

Prince William Sound

Prince William Sound (Russian: Чугацкий залив Čugatski zaliv) is a sound of the Gulf of Alaska on the south coast of the U.S. state of Alaska. It is located on the east side of the Kenai Peninsula. Its largest port is Valdez, at the southern terminus of the Trans-Alaska Pipeline System. Other settlements on the sound, which contains numerous small islands, include Cordova and Whittier plus the Alaska native villages of Chenega and Tatitlek.

Pygmy rockfish

The pygmy rockfish (Sebastes wilsoni) is a rockfish of the genus Sebastes. It is one of the smallest fish of its genus. It is reported to grow to a maximum of 23 cm (9 in) and can live up to 26 years. The rockfish lives between 30 m (98 ft) and 274 m (899 ft) of depth, and its range is in the East Pacific, for the Gulf of Alaska to Baja California, Mexico. It is colored red, which is distinctly lighter in color at the bottom, with 4 visile splothes on its dorsal spines.

Shortraker rockfish

The shortraker rockfish (Sebastes borealis) is an offshore, demersal species distributed from the southeastern Kamchatka Peninsula, Russia, to Fort Bragg, California. It attains lengths greater than one metre (>39 inches) and weighs up to 20 kg (44 pounds). In the Gulf of Alaska, shortraker rockfish are sampled annually during longline surveys and are most abundant between depths of 300–400 metres (980–1,310 ft).The Shortraker rockfish lifespan is thought to average about 120 years, the second-longest of all varieties of rockfish to the rougheye rockfish, estimated at 140 years. This makes rockfish some of the world’s oldest living fish.Commercial harvesting in the Gulf of Alaska began in the early 1960s when foreign trawl fleets were targeting more abundant species. In recent years, high catch rates indicate that the domestic trawl fleet targets this species; shortraker rockfish comprised 14.9% of the species composition of slope rockfish harvested in 1990, although trawl survey data indicates they comprised only 2.5% of the biomass.In 1991, catch limits were established for shortraker rockfish to prevent overharvesting of this species in the Gulf of Alaska. Catch limits are based on biomass estimates derived from bottom trawl catch rates. These biomass estimates are questionable, however, because the catch efficiency of bottom trawls on shortrakers is unknown. Fishermen report that shortrakers school off-bottom and above rugged habitat in steep-slope areas where bottom trawls cannot sample effectively.

Southcentral Alaska

Southcentral Alaska is the portion of the U.S. state of Alaska consisting of the shorelines and uplands of the central Gulf of Alaska. Most of the population of the state lives in this region, concentrated in and around the city of Anchorage.The area includes Cook Inlet, the Matanuska-Susitna Valley, the Kenai Peninsula, Prince William Sound, and the Copper River Valley. Tourism, fisheries, and petroleum production are important economic activities.

Arctic Ocean
Atlantic Ocean
Indian Ocean
Pacific Ocean
Southern Ocean
Endorheic basins

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