TheScotian Shelfis a geological formation, part of theContinental shelf,located southwest ofNova Scotia,Canada.[1]It covers an area of 120,000 square kilometres (46,000 sq mi),[2]is 700 kilometres (430 mi) long and ranges in width from 120 to 240 kilometres (75 to 149 mi). It has an average depth of 90 metres (300 ft).[3]The Scotian Shelf contains the ecologically important Scotian Shelf Large Marine Ecosystem (LME) and the Scotian Shelf Waters (SSW).[4][5][6]
The northeastern boundary is defined by theLaurentian Channel,where it drops off to 400 metres (1,300 ft). Further south is the continental slope, which sharply drops off to a depth of more than 3,000 metres (9,800 ft).[2]The southwestern boundary ends at theNortheast Channel,including theGulf of Maine.[3]
The Scotian Shelf is characterized by shallow, offshore banks 25 to 100 metres (82 to 328 ft) under the ocean surface, with deep basins and troughs between that vary in depth from 160 to 300 metres (520 to 980 ft).[2][3]These culminate atSable Island.[2]
A southwesterly ocean current, (occasionally containing runoff from theGulf of St Lawrence) flows over the inner shelf. The water flow over the banks is weaker and tends have greater variation.[3]The Scotian Shelf contains a canyon called the "Gully",which is more than 1,000 metres (3,300 ft) deep. Currents flow through this canyon southward, mixing offshore waters with theNova Scotia Current.This causes an increase in biological productivity toward the east, across the Continental Shelf and contains body parts from multiple decades of animals.
The Scotian Shelf is heavily influenced by theGulf Stream,resulting in a variety of marine species being present which are normally found further south. These appear at regular intervals due to the main current spinning off cores of warm water.[2]
Marine life
edit
The Scotian Shelf Large Marine Ecosystem (LME) contains numerous species, including a broad range of shellfish and fishes that use the area as spawning and nursery grounds. This abundance is the reason that the Scotian Shelf is one of the Atlantic Ocean's most fished areas.
Theright whalehas a critical habitat in theRoseway Basin,the northeastern part of the Scotian Shelf.[7]Approximately 30 percent of the known population uses this habitat throughout the course of the year.[2]
Thenorthern bottlenose whalealso lives in the Scotian Shelf Waters area, in particular, the Gully. About 230 individual specimens have been recorded there. Other species, such as thesperm whaleandharbour seal,are also found in this region, including thegrey seal,which is common on Sable Island.[2]
Various waterfowl use the coastal areas as a migratory staging area. Offshore areas are used by such birds asshearwaters,sea duckssuch as thecommon eider,andalcidssuch asdovekiesandmurres.[2]
References
edit- ^"Scotian Shelf".Geographical Names Data Base.Natural Resources Canada.
- ^abcdefghPark Establishment Branch, National Parks Directorate (2006-11-17)."Parks Canada - National Marine Conservation Areas of Canada".Pc.gc.ca. Archived fromthe originalon 2007-02-17.Retrieved2012-05-28.
- ^abcdP.C. Smith; R.J. Conover (December 16, 2013)."Scotian Shelf".The Canadian Encyclopedia.Archivedfrom the original on 2020-05-11.Retrieved2012-05-28.
- ^"Scotian Shelf large marine ecosystem".Eoearth.org.Retrieved2019-09-19.
- ^"Air-Sea CO2 fluxes on the Scotian Shelf: seasonal to multi-annual variability"(PDF).Ccg.sr.unh.edu.Retrieved27 November2017.
- ^D.W. Townsend."Biological Importance of Scotian Shelf Water"(PDF).Grampus.umeoce.maine.edu.Retrieved27 November2017.
- ^Matthews, Leanna P.; McCordic, Jessica A.; Parks, Susan E. (2014-03-19)."Remote Acoustic Monitoring of North Atlantic Right Whales (Eubalaena glacialis) Reveals Seasonal and Diel Variations in Acoustic Behavior".PLOS ONE.9(3): e91367.doi:10.1371/journal.pone.0091367.ISSN1932-6203.PMC3960123.PMID24646524.
External links
edit- Image
- Benthic habitat mapping on the Scotian Shelf based on multibeam bathymetry, surficial geology and sea floor photographs,Marine Ecology Progress Series,Vol. 219: 121–137, September 10, 2001
- The Scotian Shelf In Context:State of the Scotian Shelf Report,Fisheries and Oceans Canada,ISBN978-0-9869437-0-6
- Eastern Scotian Shelf And Barents Sea Intercomparison: Climate Fluctuation, Human Impact and System Resilience,ICES Annual Science Conference, Nantes 20.-24. September 2010