North East Atlantic Region

Environment

The North Atlantic circulation forms part of the global ocean circulation system that has been called the ‘Ocean Conveyor’ by oceanographers. The warm surface waters release heat into the cold northern atmosphere at a rate sufficient to warm the air over Europe by about 5 °C.

The major topographical features in the North East Atlantic region are the Mid-Atlantic Ridge (with the Azores and Iceland as its highest points), and the Greenland-Scotland Ridge (which separates the Atlantic Basin from the Nordic Seas). Water depths range from around 5000 m on either side of the Mid-Atlantic Ridge, to less than 200 m on the continental shelf along the European coast. In some places seamounts occur as submerged single mountains or chains of mountains along the ocean floor. The most extensive continental shelf areas are found in the North Sea and Celtic Seas.

A diverse mixture of coastal landscapes is found in the region, although generally the western margins are deeply indented with fjords, estuaries and rias and, in northern latitudes, the coast is dominated by high mountains. Around the North Sea and Celtic Sea, the coast exhibits a range of features, including cliffs of varying heights and rock types, bays and estuaries, sandy and shingle beaches, dunes and island archipelagos. Further south, the French coast of the Bay of Biscay is low-lying with lagoons. The Iberian coast comprises alternating cliffs and beaches, while cliffs predominate on the oceanic islands such as the Azores.

Uses and impacts

Many of the coastal states bordering the North-East Atlantic are densely populated, highly industrialised or use land intensively for agriculture. As a consequence, the region is affected by many human activities that result in inputs of nutrients and harmful substances, and the introduction of hazardous substances through rivers, the atmosphere and direct domestic and industrial discharges. Surrounding countries make use of the seas for fishing activities, offshore oil and gas exploration, the laying of pipelines, extraction of sand and gravel, dumping of dredged material, the laying of cable routes and energy cables and as transport routes. There is growing traffic between European States and other parts of the world, and the North Sea is one of the most frequently traversed sea territories in the world.

Many coastal zones are intensively used for recreation. In several regions there is increasing competition for the use of certain facilities and amenities on, or adjacent to, the coasts. There is growing demand for housing, commercial sites, rented accommodation and improved services. There is also an expanding market for clean beaches, watersports, angling, ecotourism and unspoilt coastal landscapes.

Biodiversity

Many species of plants and animals have restricted distributions, and the biogeographical regions give distinct characteristics in terms of biodiversity to various parts of the NE Atlantic region.

Phytoplankton biomass shows considerable spatial variability in the region. The seasonal cycle is typical of temperate latitudes with a spring increase, summer decline and a second, generally less high, autumn increase. The total number of macroalgal species decreases from south to north within the northern temperate areas. The dominating macrophytes of these areas are large, brown algae (Laminarians or ‘kelp’). In the southern part of the region the coastal environment is highly heterogeneous in terms of habitats. For this reason, the algal diversity is high.

The bathymetry of the region ranges from shallow continental shelf to abyssal plains (around 5000 m depth). Deep-ocean benthos tends to be much smaller than its shallow-water counterparts and species diversity increases with depth in the continental shelf regions to a maximum just seaward of the continental rise. Large areas of coral banks of Lophelia occur in the Atlantic Ocean near the continental shelf break off Ireland, Scotland and the Faroe Islands. High diversity of biota is associated with these coral banks.

In shallow shelf areas such as the North Sea, benthic and pelagic processes are often strongly coupled and work in concert to make the region highly productive. Highly productive benthic communities can be found in tidal areas, for example in the Wadden Sea along the south-eastern border of the North Sea, and in several estuaries along the western European coast. Highly productive frontal regions occur in the North Sea, in the Kattegat/Skagerrak area and the Irish shelf front, to the west of Ireland. Over a thousand species of fish have been recorded in the OSPAR maritime area (which extends further north than the WCPA NE Atlantic region). Of these, about 5% can be commercially exploited and about 2% of species make up 95% of the total fish biomass.

Almost all parts of the region support breeding and migratory birds dependent on the sea. Total numbers of individuals in these northern areas such as the North Sea coasts are far greater than those in the southern part of the region. Surveys show shelf seas to hold substantially higher densities than oceanic waters. Large intertidal flats, such as in estuaries and in the Wadden Sea are particularly important for wading birds.