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Patagonian Shelf marine ecoregion
Marine ecoregion boundaries (red line)
Ecology
RealmTemperate South America
ProvinceMagellanic
Geography
Area401,210 km2 (154,910 sq mi)
CountryArgentina, Chile

The Patagonian Shelf marine ecoregion covers waters offshore of Santa Cruz Province and Tiera del Feugo Province of Argentina, thus covering much of the southern areas of the Argentine Sea.[1] It has an area of 401,210 square kilometres (154,910 sq mi) and a coastline of 1,300 kilometres (810 mi). Marine biodiversity is very high due to the mixing of currents (the "Brazil-Falkland Confluence"), the mixing of fresh and salt water, the mixing of temperatures, and the broad, shallow continental shelf. Large amounts of nutrients arrive with the cold, northwest flowing Malvinas Current.

The ecoregion known for colonies of Magellanic penguins and other sea birds. The region is in the Magellanic marine province (also: Cold-temperate South American Province)[2]. It is thus part of the Temperate South America realm. [3] [4] [5]

Physical setting

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The ecoregion reaches out into the Atlantic Ocean for 250 miles from the coast, entirely on the Patagonian Shelf. A narrow ribbon stretches to the northeast, following the main flow of the Malvina Current along the continental slope. The North Patagonian Gulfs marine ecoregion lies to the west of this strip. The Patagonian Shelf ecoregion is bounded on the north by a diagonal line across the shelf, stretching from Cabo Blanco (latitude 47°S) to a point east of San Matías Gulf (latitude 41°S). The ecoregion extends for 1,300 kilometres (810 mi) to the south at the Le Maire Strait and Isla de los Estados (latitude 54°S).[2] The bordering coast is characterized by sand and pebble beaches and long, high sedimentary cliffs. Immediately inland is the Patagonian Desert terrestrial ecoregion.[2]

There are few rivers feeding the marine region; most of the flow is from the Deseado River in the north, with an estuary that stretches far inland, the Santa Cruz River to the south, and the Gallegos River in the far south on the Chilean border. The deepest point in the ecoregion overall is −1,003 metres (−3,291 ft), and the average is 68 metres (223 ft).[4] 90% of the ecoregion is less than 200 metres (660 ft) in depth.

Currents and climate

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The cold, nutrient-rich Malvinas Current (MC) (also called the Falkland Current) flows north into the region in a 100-km wide band over the Patagonian Shelf.[6] Measurements of the MC flow rate is highly variable, depending on the location ranging from 10 Sverdrups (Sv) to 88 Sv. The velocity also varies, with a typical surface drift of 40 centimetres per second (0.89 mph). Mean surface temperatures are 6 °C (43 °F).

Animals / Fish

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The marine life of the ecoregion reflects the temperate-cold, high-nutrient waters of the Malvinas Current.[2] The most commercially important fish are anchovy and Argentine hake in the north, and Fueguian sprat, Blue grenadier (hoki), blue whiting, and southern hake to the south[2].

Conservation status

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Many of the terrestrial protected areas on the coast have marine components, such that less than 1% of the ecoregion is protected, including:[4]

References

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  1. ^ "Ecoregion Mar Argentino" (PDF) (pdf) (in Spanish). Wildlife Conservation Society.
  2. ^ a b c d e "Setting Geographic Priorities for Marine Conservation in Latin America and the Caribbean" (PDF). The Nature Conservancy. Retrieved June 30, 2022.
  3. ^ Spalding, MD; Fox, Helen; Allen, Gerald; Davidson, Nick. "Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas". Bioscience. Retrieved June 30, 2022.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ^ a b c "Patagonian shelf". Digital Observatory for Protected Areas (DOPA). Retrieved March 18, 2023.
  5. ^ "Patagonian Shelf". MarineRegions.org. Retrieved March 18, 2013.
  6. ^ "The Malvinas Current". University of Miami. Retrieved March 18, 2023.