An ecoregion is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation . Ecoregions are also known as "ecozones", although that term may also refer to biogeographic realms.
A marine ecoregion is an ecoregion, or ecological region, of the oceans and seas identified and defined based on biogeographic characteristics.
The Tropical Atlantic realm is one of twelve marine realms that cover the world's coastal seas and continental shelves.
The Tropical Eastern Pacific is one of the twelve marine realms that cover the coastal waters and continental shelves of the world's oceans. The Tropical Eastern Pacific extends along the Pacific Coast of the Americas, from the southern tip of the Baja California Peninsula in the north to northern Peru in the south. It is bounded on the north by the Temperate Northern Pacific realm, and on the south by the Temperate South America realm.
Tweed–Moreton, also known as the Central Eastern Shelf Transition, is a marine biogeographic region of eastern Australia.
The Southeast Shelf Transition is a biogeographic region of Australia's coastal and continental shelf waters. It covers a portion of Australia's southeastern coast, from southern New South Wales to eastern Victoria, including the islands of the Kent Group and Furneaux Group at the eastern end of the Bass Strait. It is a provincial level bioregion in the Integrated Marine and Coastal Regionalisation of Australia (IMCRA) system, and is a transitional region between the warm temperate Central Eastern Shelf Province to the northwest and the cool temperate Bass Strait Shelf and Tasmanian Shelf provinces to the west and south. It corresponds to the Cape Howe marine ecoregion in the WWF's Marine Ecoregions of the World system.
The Southwest Shelf Transition, also known as the Houtman marine ecoregion, is a biogeographic region of Australia's continental shelf and coastal waters. It includes the subtropical coastal waters of Southwest Australia.
The Western Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the eastern and central Indian Ocean. It is part of the larger Indo-Pacific, which includes the tropical Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia. The Western Indo-Pacific may be classified as a marine realm, one of the great biogeographic divisions of the world's ocean basins, or as a subrealm of the Indo-Pacific.
The Central Indo-Pacific is a biogeographic region of Earth's seas, comprising the tropical waters of the western Pacific Ocean, the eastern Indian Ocean, and the connecting seas.
The Temperate Northern Pacific is a biogeographic region of the Earth's seas, comprising the temperate waters of the northern Pacific Ocean.
Temperate Southern Africa is a biogeographic region of the Earth's seas, comprising the temperate waters of southern Africa, where the Atlantic Ocean and Indian Ocean meet. It includes the coast of South Africa and Namibia, and reaches into southern Angola. It also includes the remote islands of Amsterdam and Saint-Paul, to the east in the southern Indian Ocean.
Temperate Australasia is a biogeographic region of the Earth's seas, comprising the temperate and subtropical waters of Australia and New Zealand, including both the Indian Ocean and Pacific coasts of the continent and adjacent islands.
The Eastern Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters around island groups in the central Pacific Ocean. It includes most of Polynesia, except for New Zealand and the Kermadec Islands. It also includes the Marshall Islands and Kiribati from Micronesia. It adjoins the Central Indo-Pacific realm to the west, which encompasses Melanesia and the other island groups of Micronesia.
The Temperate Northern Atlantic is a biogeographic region of the Earth's seas, comprising the temperate and subtropical waters of the North Atlantic Ocean and connecting seas, including the Mediterranean Sea, Black Sea, and northern Gulf of Mexico.
The Magdalena Transition is a marine ecoregion in the eastern Pacific Ocean. It includes the coastal waters along the southwestern Baja California Peninsula, extending from Punta Abreojos in the north to Cabo San Lucas at the peninsula's southern tip.
The Southeastern Brazil marine ecoregion covers the warm coastal waters to 250 miles offshore of southeastern Brazil, from the latitude of Rio de Janeiro in the north to Florianópolis in the south. Marine diversity is supported by local upwellings in the north and the inflow of the Brazil Current. The region is one of transition from a tropical to a warm temperate environment. The marine ecoregion is one of four coastal marine ecoregions in the Warm Temperate Southwestern Atlantic marine province. It is thus part of the Temperate South America realm. .
The Uruguay - Buenos Aires Shelf marine ecoregion covers waters offshore of Uruguay, the mouth of the Rio de la Plata), and Buenos Aires Province of Argentina. It has an area of 258,490 square kilometres (99,800 sq mi) and a coastline of 1,300 kilometres (810 mi). Marine biodiversity is very high due to the mixing of currents, the mixing of fresh and salt water, the mixing of temperatures, and the broad, shallow continental shelf. Large amounts of nutrients arrive from the northwest flowing Malvinas Current and from the continental runoff of the Rio de la Plata. Aside from high populations of fish there are colonies of marine mammals, sea turtles, and seabirds.
The Rio de la Plata marine ecoregion covers the mouth of the Rio de la Plata, between the shores of Argentina an Uruguay and inshore of the continental shelf of the Uruguay - Buenos Aires Shelf marine ecoregion. The ecoregion is an important reproductive and nursery ground for marine life, as the river runoff provides nutrients for larval and juvenile phases, the shallow and protective waters admit light, and there is of mixing fresh and salt waters. The region is in the Warm Temperate Southwest Atlantic marine province, a part of the Tropical Atlantic realm. .
