A marine ecoregion is an

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) 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 ...

, or ecological region, of the

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...

s and seas identified and defined based on

biogeographic Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, ...

characteristics.

Introduction

A more complete definition describes them as “Areas of relatively homogeneous species composition, clearly distinct from adjacent systems” dominated by “a small number of ecosystems and/or a distinct suite of oceanographic or topographic features”. Ecologically they “are strongly cohesive units, sufficiently large to encompass ecological or life history processes for most sedentary species.”Spalding, Mark D., Helen E. Fox, Gerald R. Allen, Nick Davidson et al. "Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas". Bioscience Vol. 57 No. 7, July/August 2007, pp. 573–58

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Marine Ecoregions of the World—MEOW

The global classification system Marine Ecoregions of the World—MEOW was devised by an international team, including major conservation organizations, academic institutions and intergovernmental organizations. The system covers coastal and continental shelf waters of the world, and does not include deep ocean waters. The MEOW system integrated the biogeographic regionalization systems in use at national or continental scale, like Australia's

Integrated Marine and Coastal Regionalisation of Australia The Integrated Marine and Coastal Regionalisation of Australia (IMCRA), formerly the Interim Marine and Coastal Regionalisation for Australia, is a biogeographic regionalisation of the oceanic waters of Australia's exclusive economic zone (EE ...

and the Nature Conservancy’s system in the Americas, although it often uses different names for the subdivisions. This system has a strong biogeographic basis, but was designed to aid in

conservation Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and managem ...

activities for

marine ecosystems Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the su ...

. Its subdivisions include both the seafloor ( benthic) and shelf pelagic (

neritic The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminate ...

) biotas of each marine region. The digital ecoregions layer is available for download as an ArcGIS Shapefile.

Subdivisions

Ecoregions

The Marine Ecoregions of the World classification defines 232 marine ecoregions (e.g.

Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...

, Cortezian, Ningaloo,

Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who ...

) for the coastal and shelf waters of the world.

Provinces

These marine ecoregions form part of a nested system and are grouped into 62 provinces (e.g. the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phi ...

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

, Central Indian Ocean Islands).

Realms

The provinces in turn, are grouped into 12 major realms. The latter are considered analogous to the eight terrestrial

realms A realm is a community or territory over which a sovereign rules. The term is commonly used to describe a monarchical or dynastic state. A realm may also be a subdivision within an empire, if it has its own monarch, e.g. the German Empire. Et ...

, represent large regions of the ocean basins: #

Arctic The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), Finland, Iceland, N ...

Temperate Northern Atlantic 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 Mexic ...

# Temperate Northern Pacific # Tropical Atlantic #

Western Indo-Pacific 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 centra ...

# Central Indo-Pacific # Eastern Indo-Pacific #

Tropical Eastern Pacific 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 t ...

# Temperate South America # Temperate Southern Africa #

Temperate Australasia 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. Tempera ...

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

Other marine ecoregion classifications

Other classifications of marine ecoregions or equivalent areas have been widely developed at national and regional levels, as well as a small number of global schemes. Each of these systems, along with numerous regional biogeographic classifications, was used to inform the MEOW system. The WWF Global 200 work also identifies a number of major habitat types that correspond to the terrestrial biomes: polar, temperate shelves and seas, temperate upwelling, tropical upwelling, tropical coral, pelagic (trades and westerlies), abyssal, and hadal (ocean trench). ;Briggs Coastal Provinces One of the most comprehensive early classifications was the system of 53 coastal provinces developed by Briggs in 1974. The near-global system of 64 large marine ecosystems has a partial biogeographic basis. ;WWF Global 200 The

World Wildlife Fund The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the Wo ...

—WWF identified 43 priority marine ecoregions, as part of its

Global 200 The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature ( WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or w ...

initiative.Olson DM, Dinerstein E. 2002; "The Global 200: priority ecoregions for conservation"; Annals of the Missouri Botanical Garden 89: 199-224

References

External links

Nature.org: Marine Ecoregions of the World—MEOW
{{Modelling ecosystems, expanded=none Aquatic ecology * Marine biology Fisheries science Marine botany Oceanographical terminology