Cordell Bank National Marine Sanctuary
Cordell Bank National Marine Sanctuary | |
---|---|
Location | Cordell Bank, California, United States |
Coordinates | 38°04′00″N 123°22′04″W / 38.06659°N 123.36778°W[1] |
Area | 1,286 sq mi (3,330 km2) |
Established | 1989 |
Governing body | NOAA National Ocean Service |
cordellbank |
Cordell Bank National Marine Sanctuary is a
Cordell Bank is one of the United States' 13
The unique blend of ocean conditions and undersea topography creates a rich and diverse underwater ecosystem. A subsurface island rises from soft sediments covering the continental shelf. The upper pinnacles reach to within 115 ft (35 m) of the surface, and the average depth is 400 ft (122 m). The sanctuary serves as a breeding ground for migratory marine mammals, birds, and fish. The prevailing California Current flows southward along the coast, causing an upwelling of nutrient-rich water that provided the foundation for the area's marine ecosystem.[2]
Sanctuary regulations prohibit extraction of hydrocarbons (oil, natural gas), the removal of
Geological setting
Cordell Bank was originally created 93 million years ago, as a member of the
Between 20,000 and 15,000 years ago the sea level in the area was 360 ft (110 m) below the current level, leaving most of Cordell Bank exposed and making it a true island. Today the bank rises out of soft sediment, deposited on the bank more recently by coastal erosion. Within just 7 mi (11,265 m) of Cordell Bank, the continental shelf drops to over 1 mi (2 km) deep.[4] The seamount is largely composed of granite.
History
Coastal California has a rich history of marine utilization by Native Americans and early settlers. Cordell Bank was a mystery prior to the 19th century because neither the Miwok natives nor the settlers had any incentive to venture far out from shore, when food resources were available close to shore. Many European mariners sailed right over Cordell Bank without even knowing it was there.[5]
In the later half of the 1800s there was a strong incentive to survey the coast of California so as to promote maritime safety. Cordell Bank was discovered in 1853 by George Davidson of the United States Coast Survey during a mapping expedition on California's north coast.[5][6]
In 1869 Edward Cordell (the reserve's namesake) was sent to collect additional information on a "shoal west of Point Reyes". He found the area by following the numerous birds and marine mammals. To measure the depth, Cordell lowered a lead weight into the water until it hit the bottom and then measured the length of the line on its return to the surface.[6] The area was considered a productive fishing area, but not much was discovered about its marine life until an expedition in 1977.[5]
NOAA carried out a detailed multibeam echosounder survey of the area in 1985 from aboard the R/V Davidson.[6]
The expedition was led by a
Expansion
A bill (H.R. 5352) was proposed to Congress by Representative
In 2012, the
Expansion was passed March 2015.[9]
Biology
26 species of marine mammals, including whales, dolphins, seals, and sea lions, are known to frequent the waters of the sanctuary. In addition, Cordell Bank is one of the most important feeding grounds in the world for the endangered blue and humpback whales; these species travel all the way from their breeding grounds in coastal Mexico and Central America to feed on the krill that aggregate near the bank. Another unique species is the Pacific white-sided dolphin (Sagmatias obliquidens), which can be seen in large numbers. Other visitors include California sea lions (Zalophus californianus), northern elephant seals (Mirounga angustirostris), northern fur seals (Callorhinus ursinus), and Steller sea lions (Eumetopias jubatus), all of which are attracted to the abundance in krill, squid, and juvenile fish.[10] Leatherback sea turtles also inhabit sanctuary waters.
Cordell Bank is also a major foraging ground for passing seabirds. Known as the "Albatross capital of the world," 5 of the 14 major species of albatross have been documented there. The two most common are the black-footed albatross (Phoebastria nigripes) and sooty shearwater (Puffinus griseus). It is also one of the few places to see a short-tailed albatross (Phoebastria albatrus), which is extremely rare; the species was thought to have gone extinct after World War II. Currently the world population hovers at around 1000 individuals.[10]
Cordell Bank is also known for its abundance of fish.
Although far from shore,
Ecologic cycle
This unusual granite mountain is surrounded on three sides by deep waters, which allows the flow of deep nutrient-rich waters over relatively shallow waters with sufficient light to support photosynthesis.
The ecological cycle at Cordell Bank can be divided into three oceanographic seasons. During the spring, strong northwestern winds push the water southward along the California coast. Gale winds and the Earth's rotation drive surface water away from the shore, only to be replaced by an upwelling of more nutrient-rich waters from offshore. this contributes to the growth in numbers of phytoplankton, which are the foundation of the marine food web, in turn leading to a rise in the food supply, and thus numbers, of the organisms higher up the chain.[11]
During the late summer and fall seasons, the coastal winds that stirred up the deeper waters die down, and the northward-flowing Davidson Current prevails, bringing warm but nutrient-poor water from the south.[11]
During the winter storm months, the sea is dominated by rough weather, which mixes the deeper water with that above. The temperature on top of the continental shelf mixes, and the temperature, salinity, and the concentration of nutrients in them are assimilated.[11]
See also
References
- ^ U.S. Geological Survey Geographic Names Information System: Cordell Bank National Marine Sanctuary
- ^ NOAA. Retrieved 25 November 2009.
- ^ "Cordell Bank National Marine Sanctuary" at NOAA.gov
- ^ NOAA. Retrieved 26 November 2009.
- ^ NOAA. Retrieved 26 November 2009.
- ^ a b c d Schmieder, RW (1985). "The expeditions to Cordell Bank". In: Mitchell, CT (Ed). Diving for Science…1985. Proceedings of the Joint American Academy of Underwater Sciences and Confédération Mondiale des Activités Subaquatiques annual scientific diving symposium 31 October - 3 November 1985 la Jolla, California, USA. Archived from the original on 5 July 2013. Retrieved 27 May 2013.
{{cite journal}}
: CS1 maint: unfit URL (link) - United States Government Printing Office. Retrieved 27 May 2013.
- ^ "Feds propose to expand 2 Calif. Marine sanctuaries - Business | NBC News". www.msnbc.msn.com. Archived from the original on 31 December 2012. Retrieved 13 January 2022.
- ^ "NOAA expands Cordell Bank, Gulf of the Farallones marine sanctuaries off California". Phys.org. Retrieved 5 April 2022.
- ^ NOAA. Retrieved 26 November 2009.
- ^ NOAA. Retrieved 26 November 2009.
Works cited
- "A National Marine Sanctuary: Cordell Carpenter Bank," Published by the National Marine Sanctuary Program of the National Oceanic and Atmospheric Administration (NOAA)
- Schmieder, Robert W., 1991, Ecology of an Underwater Island, Published by Cordell Expeditions, Walnut Creek, CA, http://www.cordell.org. See also: Schmieder Bank
- Stallcup, Richard. 1990. Ocean Birds of the Nearshore Pacific, Point Reyes Bird Observatory, Stinson Beach, CA. 214 pp.