coast

coast, land bordering an ocean or other large body of water. The line of contact between the land and water surfaces is called the shoreline. It fluctuates with the waves and tides. Sometimes the terms coast and shore are used synonymously, but often shore is interpreted to mean only the zone between the shorelines at high tide and low tide, and coast indicates a strip of land of indefinite width landward of the shore. Classically, coasts have been designated as submergent if they resulted from a rise in the relative sea level and emergent if they resulted from a decline. Young submergent coasts usually are irregular and have deep water offshore and many good harbors, either bays or estuaries. Much of the coast of New England and most of the Atlantic coast of Europe are young submergent coasts according to this classification scheme. Gradually the submergent coast, subjected to erosive attacks of the ocean and other agents, becomes mature. Headlands are worn back to form cliffs, at the base of which deposits of eroded material accumulate as fringing beaches; spits and bars also grow up from material that is carried by currents and deposited in deeper water. The shoreline is called mature when it is smooth, the headlands having been cut away and the bays either filled up or closed off by spits. Emergent shorelines usually have shallow water for some distance offshore. Such shorelines are found along the Atlantic coast of the SE United States and along part of the coast of Argentina, near the Río de la Plata. This classification system does not adequately describe many coasts, partly because many of them exhibit features of both submergence and emergence. Because of these and other problems a classification system that is based on the most recent and predominant geologic agent forming the coast has become popular. Under this scheme, there are essentially two major types of coasts. Primary coasts are youthful coasts formed where the sea rests against a land mass whose topography was formed by terrestrial agents. These coasts include land erosion coasts (Maine), volcanic coasts (Hawaii), deposition coasts (Nile Delta coast), and fault coasts (Red Sea). Secondary coasts are formed chiefly and most recently by marine agents, and may even be primary coasts that have been severely modified by wave action. These coasts include wave erosion coasts, marine deposition coasts, and coasts built by organisms (reefs and mangrove coasts). The nature of the coastline of a country or a state is an important factor in its economic development because it relates to defense, fishing, recreation, and overseas commerce.

or sequoia

Coniferous evergreen timber tree (Sequoia sempervirens) of the family Taxodiaceae, found in the fog belt of west-coastal North America. It grows in the coastal range from southwestern Oregon to central California at elevations up to 3,300 ft (1,000 m). The genus name commemorates the Cherokee Indian Sequoyah. The redwood is sometimes called coast redwood to distinguish it from the Sierra redwood (or big tree) and the Japanese redwood (or Japanese cedar). Redwoods are the tallest living trees, often exceeding 300 ft (90 m) in height; one has reached 368 ft (112 m). Typical trunk diameters are 10–20 ft (3–6 m) or more. The redwood tree takes 400–500 years to reach maturity; some are known to be more than 1,500 years old. As the tree ages, the lower limbs fall away, leaving a columnar trunk. Redwood timber has been used for furniture, shingles, fence posts, paneling, and fine wood objects. Today many of the remaining redwood stands are protected (see Redwood National Park; Sequoia National Park). Seealso dawn redwood.

Learn more about redwood with a free trial on Britannica.com.

Coniferous, nonevergreen tree (Metasequoia glyptostroboides), the only living species of the genus Metasequoia, of the family Taxodiaceae, native to remote valleys of central China. Both branchlets and leaves grow out in pairs from points along the stem. The bright green, feathery leaves turn reddish brown in autumn. Though Metasequoia fossils are abundant, the tree was thought to be extinct until living specimens were discovered in the 1940s. Only a few thousand are known to have survived, in central China. Since these stands were discovered, seeds and cuttings have been planted throughout the world.

Learn more about dawn redwood with a free trial on Britannica.com.

National park, northwestern corner of California, U.S. It was established in 1968, expanded in 1978, and designated a World Heritage site in 1980. It preserves virgin groves of ancient redwood trees, including the world's tallest, 367.8 ft (112.1 m) high. It also includes 40 mi (65 km) of scenic Pacific coastline. It covers an area of 172 sq mi (445 sq km), including land in three state parks.

Learn more about Redwood National Park with a free trial on Britannica.com.

or shore

Broad area of land that borders the sea. The coastlines of the world's continents measure about 193,000 mi (312,000 km). They have undergone shifts in position and changes in shape over geologic time because of substantial changes in the relative levels of land and sea. Other factors that alter coasts are erosion processes such as wave action and weathering, deposition of rock debris by currents, and tectonic activity. Coastal features result largely from the interaction and relative intensity of these processes, though the type and structure of the underlying rocks also play a part.

Learn more about coast with a free trial on Britannica.com.

formerly Trucial States

Country, Middle East, southwestern Asia. It is a federation of seven states on the eastern coast of the Arabian Peninsula. They are the emirates of Abū Zsubdotabī (Abu Dhabi), Dubayy (Dubai), aynAjmān, Al-Shāriqah (Sharjah), Umm al-Qaywayn, Rahamzahs al-Khaymah, and Al-Fujayrah. Area: 32,280 sq mi (83,600 sq km). Population (2005 est.): 4,690,000. Capital: Abu Dhabi. The indigenous inhabitants are Arabs, but there are a large number of South Asian and Iranian migrant workers. Languages: Arabic (official), English, Persian, Urdu, Hindi. Religions: Islam (official; predominantly Sunni); also Christianity, Hinduism. Currency: UAE dirham. The UAE's low-lying desert plain is broken by the Hsubdotajar Mountains along the Musandam Peninsula. Three natural deepwater harbours are located along the Gulf of Oman. The UAE (mainly Abū Zsubdotabī) has roughly one-tenth of the world's petroleum reserves and significant natural gas deposits, the production of which are the federation's principal industries. Other important economic activities include fishing, livestock herding, and date production. The federation has one appointive advisory board; its chief of state is the president, and the head of government is the prime minister. In 1820 the British signed a peace treaty with the region's coastal rulers. The area, formerly called the Pirate Coast, became known as the Trucial Coast. In 1892 the rulers agreed to entrust foreign relations to Britain, but the British never assumed sovereignty; each state maintained full internal control. The states formed the Trucial States Council in 1960 and in 1971 terminated defense treaties with Britain and established the six-member federation. Rahamzahs al-Khaymah joined it in 1972. The UAE aided coalition forces against Iraq in the Persian Gulf War (1990–91).

Learn more about United Arab Emirates (UAE) with a free trial on Britannica.com.

or Miskito Coast

Region along the coast of eastern Nicaragua and Honduras. It comprises a lowland about 40 mi (65 km) wide that skirts the Caribbean Sea for about 225 mi (360 km). It was visited by Christopher Columbus in 1502, but Europeans had little contact with the area until the rise of the buccaneers in the 17th century, after which England established a protectorate there. It is named for the Miskito Indians. Spain, Nicaragua, and the U.S. disputed England's protectorate until the Clayton-Bulwer Treaty (1850). In 1894 the region was incorporated into Nicaragua, but the northern part was granted to Honduras in 1960 by the International Court of Justice. The chief town is Bluefields, at the mouth of the Escondido River in Nicaragua.

Learn more about Mosquito Coast with a free trial on Britannica.com.

Region, southwestern coast of India, stretching from the Western Ghats to the Arabian Sea. It now includes most of Kerala state and the coastal region of Karnataka state. It has sometimes been used to refer to the entire western coast of peninsular India. A large part of it was within the ancient kingdom of Keralaputra. The Portuguese established trading posts there; they were followed by the Dutch in the 17th century and the French in the 18th century. The British gained control of the region in the late 18th century.

Learn more about Malabar Coast with a free trial on Britannica.com.

or Ivory Coast officially Republic of Côte d'Ivoire

Encyclopædia Britannica, Inc.Country, western Africa. Area: 123,863 sq mi (320,803 sq km). Population (2008 est.): 19,624,000. Capital: Yamoussoukro; de facto capital Abidjan. The population consists of various ethnic groups, notably the Akan and Mande. Languages: French (official), Baule, Anyi, Bete, Bambara, Dan. Religions: Islam, Christianity, traditional beliefs. Currency: CFA franc. Côte d'Ivoire can be divided into four major regions: a narrow coastal region, an equatorial rainforest in the west, a cultivated forest zone in the east, and a savanna region in the north. Agriculture employs about half the workforce. The country is a major producer of cocoa and petroleum; other exports include timber and wood products and coffee. It is a republic with one legislative house; its chief of state and government is the president, assisted by the prime minister. European powers came to the area to trade in ivory and slaves beginning in the 15th century, and local kingdoms gave way to French influence in the 19th century. The French colony of Côte d'Ivoire was founded in 1893, and full French occupation took place in 1908–18. In 1946 it became a territory in the French Union; in 1947 the northern part of the country separated and became part of Upper Volta (now Burkina Faso). Côte d'Ivoire peacefully achieved autonomy in 1958 and independence in 1960, when Félix Houphouët-Boigny was elected president. The country's first multiparty presidential elections were held in 1990. Political turmoil has persisted since Houphouët-Boigny died in 1993, and a civil war in 2002 left the country divided into northern and southern sections. Attempts at reconciliation were initiated over the following years, including a 2007 power-sharing agreement signed by both sides.

Learn more about Côte d'Ivoire with a free trial on Britannica.com.

Section of the coast of the Gulf of Guinea, western Africa. Extending approximately from Axim, Ghana, in the west to the Volta River in the east, it was so called because it was an important source of gold. It was an area of intense colonial rivalry from the 17th century. Acquired as a colony by the British in the 19th century and named the Gold Coast, the area achieved independence as the Republic of Ghana in 1957.

Learn more about Gold Coast with a free trial on Britannica.com.

Mediterranean coastal region, North Africa. It extends from Egypt to the Atlantic Ocean. Once part of Roman Africa, the region was overrun by Vandals in the 5th century AD. Reconquered by the Eastern Roman Empire (Byzantine Empire) circa AD 533, it was overcome by Arabs during the 7th century and was eventually broken up into the independent Muslim polities known collectively as the Barbary states (Morocco, Algeria [Algiers], Tunisia [Tunis], and Libya [Tripoli]). For centuries the coast was notorious as a haven for pirates, who ravaged shipping and collected tribute from European states. After the U.S. war with Tripoli (see Tripolitan War), the U.S. expedition to Algiers (1815), and the bombardment of Algiers by the British (1816), the pirates ceased exacting tribute.

Learn more about Barbary Coast with a free trial on Britannica.com.

The coast is defined as the part of the land adjoining or near the ocean. A coastline is properly a line on a map indicating the disposition of a coast, but the word is often used to refer to the coast itself. The adjective coastal describes something as being on, near to, or associated with a coast.

Coast is a specific term, and is applied to that part of an island or continent that borders an ocean or its saltwater tributaries. A pelagic coast refers to a coast which fronts the open ocean, as opposed to a more sheltered coast in a gulf or bay. A shore on the other hand, can refer to parts of the land which adjoin any large body of water, including oceans (sea shore) and lakes (lake shore). Similarly, the somewhat related term bank refers to the land alongside or sloping down to a river (river bank) or of a body of water smaller than a lake. Bank is also used in some parts of the world to refer to an artificial ridge of earth intended to retain the water of a river or pond. In other places this may be called a levee.

While many scientific experts might agree on a common definition of the term "coast", the delineation of the inland extents of a coast differ according to jurisdiction, with many scientific and government authorities in various countries differing for economic and social policy reasons. This is usually because defining lands as part of a coast may be seen to have environmental implications which would prevent development or attach regulations to their use.

Environmental importance

The coast and its adjacent areas on and off shore is an important part of a local ecosystem as the mixture of fresh water and salt water in estuaries provides many nutrients for marine life. Salt marshes and beaches also support a diversity of plants, animals, and insects crucial to the food chain.

Like the ocean which shapes them, coasts are a dynamic environment with constant change. The earth's natural processes, particularly sea level rise, waves and various weather phenomena, have resulted in the erosion, accretion and reshaping of coasts as well as flooding and creation of continental shelves and drowned river valleys (rias).

The high level of biodiversity creates a high level of biological activity, which has attracted human activity for thousands of years. Due to extraordinary population growth in the 20th century, tremendous pressures have been placed on the planet’s ecosystems. With a larger population we must provide more housing, energy, and food. The problem exists both in the concentration of people in coastal areas and their sheer numbers. In the Mancote Mangroves of St. Lucia, harvesting mangrove for timber and clearing for fishing drove the mangrove forests to dangerously low levels. This disruption resulted in a loss of habitat and spawning ground for marine life that was unique to the area. These mangrove forests also helped to stabilize the coastlines. St. Lucia was faced with a huge mess and fortunately have been able to make great conservation efforts since the 80’s that has partially restored the ecosystem functioning.

Human impacts

Coasts also face many environmental challenges relating to human-induced impacts. The human influence on climate change is thought to be a contributing factor of an accelerated trend in sea level rise which threatens coastal habitat as natural systems struggle to adapt faster. Human development of coastal land, particularly for recreational or industrial uses are similarly threatened by sea level rise, but also contribute to aesthetic problems of land use and reduced natural coastal habitat.

Pollution is an ongoing concern along coasts with garbage and industrial debris littering beaches and sometimes entire coasts, requiring government agencies to make frequent use of beach cleaners and other volunteer cleanup efforts. The transportation of petroleum in tankers is a major hazard both for the open ocean and along coasts, particularly when large oil spills occur. Another major hazard for coastal marine life is the large number of small oil spills created by large and small vessels powered by petroleum which flush bilge water directly into the ocean.

Both the terms coast and coastal are often used to describe a geographic location or region. For example, New Zealand's West Coast, or the East and West Coasts of the United States.

A large part of the global population inhabits areas near a coast, partly to take advantage of marine resources such as fish, but more importantly to participate in seaborne trade with other nations. Many of the world's major cities that have developed in recent centuries were built on or near good harbours and have large port facilities to take advantage of marine transportation. Jurisdictions which are landlocked and have no coast are often at an economic disadvantage with overseas trade being more difficult; sometimes being forced to go to extravagant measures such as building canals to permit ocean-going vessels to travel inland.

Coasts, especially those with beaches and warm water are also an important draw for tourists. In many island nations such as those of the Mediterranean, South Pacific and Caribbean, tourism by those who come to enjoy the coast is central to the economy. Coasts are popular destinations because of recreational activities such as swimming, fishing, surfing, boating, and sunbathing. Growth management can be a challenge for coastal local authorities who often struggle to provide the infrastructure required by new residents seeking seachange lifestyles.

Many tourists and residents also enjoy the salt air by the sea coast which some consider to have health benefits. Coastal weather is heavily influenced by the ocean and while this can sometimes result in dangerous storms such as Nor'easters and hurricanes, the coastal climate is often cooler and more temperate than corresponding inland areas. Consequently tourists from areas experiencing extremely warm and humid weather seek coastal areas for these reasons.

Fisheries have lost much of their capacity to produce fish due to habitat degradation, and over-fishing. Overharvesting, trawling, bycatch and climate change are among some of the major pressures on fisheries. Since the growth of the global fishing enterprise since the 1950’s, intensive fishing has gone from a few concentrated areas to encompass nearly all fisheries. Not only is over fishing a problem but the technology involved creates even greater destruction. Trawling, or bottom dragging, is used for catching shrimp and other bottom dwelling species. This scraping of the ocean floor is devastating to coral, sponges and other long-lived species that do not recover quickly. This destruction alters the functioning of the ecosystem and can permanently alter species composition and biodiversity. Bycatch is the result of capturing unintended species in the course of fishing. Of this unintended catch most is discarded back into the ocean and dies from injuries or exposure. Bycatch represents approximately ¼ of all marine catch. In the case of shrimp capture, the amount of bycatch is five times larger than the amount of shrimp caught.

The coast is often a crucial defensive frontier, both for warding off military invaders but also smugglers and illegal migrants. Coastal defenses have thus long been erected in many nations. Most coastal countries also have a navy and some form of coast guard.

Types of coast

An emergent coastline is a coastline which has experienced a fall in sea level, because of either a global sea level change, or local uplift. Emergent coastlines are identifiable by the coastal landforms, which are above the high tide mark, such as raised beaches. Alternatively, a submergent coastline is a coastline which has experienced a rise in sea level, due to a global sea level change, local subsidence, or isostatic rebound. Submergent coastlines are identifiable by their submerged, or "drowned" landforms, such as rias (drowned valleys) and fjords.

A concordant coastline is a coastline where bands of different rock types run parallel to the shore. These rock types are usually of alternating resistance, so the coastline forms distinctive landforms, such as coves. A discordant coastline is a type of coastline formed when rock types of alternating resistance run perpendicular to the shore. Discordant coastlines feature distinctive landforms because the rocks are eroded by ocean waves. The less resistant rocks erode faster, creating inlets or bays; the more resistant rocks erode more slowly, remaining as headlands or outcroppings.

Coastal landforms and features

• Bay
• Cape
• Cove
• Gulf
• Headland
• Peninsula

Cliff erosion

• Cave
• Cliff
• Natural arch
• Stack
• Stump
• Wave cut cliff
• Wave cut notch
• Wave cut platform

Rivers on the coastline

• Delta
• Estuary

Coastal features formed by sediment

• Beach
• Beach cusps
• Boondock
• Dune system
• Mud flat
• Raised beach
• Ria
• Shoal
• spit
• Surge channel
• Tombolo

Coastal features formed by another feature

• Lagoon
• Salt marsh

Other features on the coast

• Concordant coastline
• Discordant coastline
• Fjord
• Island
• Island arc
• Machair

Coastal processes

• Attrition
• Currents
• Denudation
• Deposition
• Erosion
• Flooding
• Longshore drift
• Saltation
• Sea level change

*eustatic

*isostatic

• Sedimentation

*sediment transportation

*solution

*sub-aerial processes

*suspension

• Tides
• Water waves

*diffraction

*refraction

*wave breaking

*wave shoaling

• Weathering

Wildlife

Animals

Animals living along the coast vary enormously, some live along coasts to nest like puffins, sea turtles and rockhopper penguins. Sea snails and various kinds of barnacles live on the coast and scavenge on food deposited by the sea. Most coastal animals are used to humans in developed areas, such as dolphins and seagulls who eat food thrown for them by tourists. Since the coastal areas are all part of the littoral zone, there is a profusion of marine life found just off-coast.

There are many kinds of seabirds on the coast. Pelicans and cormorants join up with terns and oystercatchers to forage for fish and shellfish on the coast.

Plants

Coastal areas are famous for their kelp beds. Kelp is a fast growing seaweed that grows up to a metre a day. Corals and anemones are true animals, but live a similar lifestyle as plants do.

See also

• Coastal and Estuarine Research Federation
• Coastal erosion
• Coastal management
• Coral reefs
• Earth science
• Engineering geology
• Geography
• Geology
• Geomorphology
• How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension
• Lake
• Land reclamation
• List of countries by length of coastline
• List of places on land with elevations below sea level
• List of U.S. states by coastline
• Marine biology
• Marine debris
• Marine life
• Nautical chart
• NOAA
• Ocean
• Pole of inaccessibility: the locations farthest from any coastline.

References

• Burke, Lauretta A., Yumiko Kura, Ken Kassem, Carmen Revenga, Mark Spalding, and Don McAllister. "Coastal Ecosystems." Pilot Analysis of Global Ecosystems. 2001. World Resources Institute. 15 May 2007 .
• Tundi Agardy and Jacqueline Alder. “Coastal Systems.” Ecosystems and Current Well-being: Current State and Trends. 2005. Millennium Ecosystem Assessment. 11 May 2007
• United Nations Development Programme, United Nations Environment Programme, World Bank, World Resources Institute. “Taking Stock of Ecosystems.” World Resources 2000-2001. Pg 69-86. World Resources Institute Washington D.C.
• United Nations Development Programme, United Environment Programme, World Bank, World Resources Institute. “Village By Village.” World Resources 2005. Pg 144-151. World Resources Institute Washington D.C.
• United Nations Development Programme, United Environment Programme, World Bank, World Resources Institute. “Threats to Coastal Ecosystems. World Resources 1996-97. World Resources Institute. 22 May 2007

External links

• UK Coast Guide
• Preserving the coasts
• NOS Data Explorer - A portal to obtain NOAA National Ocean Service data