coast

File:Somalia 16.08.2009 08-30-13.jpg has the longest coastline in Africa.[https://www.researchgate.net/publication/222296321_The_Indian_Ocean_Coast_of_Somalia "The Indian Ocean Coast of Somalia"]. Marine Pollution Bulletin. 41 (1–6): 141–159. December 2000. doi: 10.1016/S0025-326X(00)00107-7]]

The Earth has approximately {{convert|620000|km|mi}} of coastline. Coastal habitats, which extend to the margins of the continental shelves, make up about 7 percent of the Earth's oceans,{{cite web |title=Ocean Habitats |url=https://www.nps.gov/subjects/oceans/ocean-habitats.htm |website=Oceans, Coasts & Seashores |publisher=National Park Service |access-date=25 September 2021 |date=1 December 2016}} but at least 85% of commercially harvested fish depend on coastal environments during at least part of their life cycle.{{cite journal |last1=Lellis-Dibble |first1=K.A. |last2=McGlynn |first2=K.E. |last3=Bigford |first3=T.E. |year=2008 |title=Estuarine fish and shellfish species in US commercial and recreational fisheries: economic value as an incentive to protect and restore estuarine habitat |journal=NOAA Technical Memo |volume=NMFS-F/SPO |url=https://repository.library.noaa.gov/view/noaa/3612 |access-date=24 September 2021}} {{asof|October 2010|post=,}} about 2.86% of exclusive economic zones were part of marine protected areas.{{cite web |url=http://www.iucn.org/knowledge/publications_doc/publications/?6500/Global-ocean-protection--present-status-and-future-possibilities/ |title=Global Ocean Protection: Present Status and Future Possibilities |publisher=Iucn.org |date=2010-11-23 |access-date=2012-06-07 |archive-date=2012-03-19 |archive-url=https://web.archive.org/web/20120319150750/http://www.iucn.org/knowledge/publications_doc/publications/?6500/Global-ocean-protection--present-status-and-future-possibilities/ }}

The definition of coasts varies. Marine scientists think of the "wet" (aquatic or intertidal) vegetated habitats as being coastal ecosystems (including seagrass, salt marsh etc.) whilst some terrestrial scientists might only think of coastal ecosystems as purely terrestrial plants that live close to the seashore (see also estuaries and coastal ecosystems).

While there is general agreement in the scientific community regarding the definition of coast, in the political sphere, the delineation of the extents of a coast differ according to jurisdiction.{{citation needed|date=August 2021}}{{Cite web |title="The Coast" is Complicated: A Model to Consistently Describe the Nation's Coastal Population |url=https://coast.noaa.gov/htdata/SocioEconomic/the_coast_is_complicated_april_2013.pdf |url-status=live |archive-url=https://web.archive.org/web/20230614012437/https://coast.noaa.gov/htdata/SocioEconomic/the_coast_is_complicated_april_2013.pdf |archive-date=June 14, 2023 |access-date=June 13, 2023 |website=NOAA}} Government authorities in various countries may define coast differently for economic and social policy reasons.

{{excerpt|Coastline paradox|paragraphs=1,2|files=0}}

File:Porto Covo pano April 2009-4.jpg, west coast of Portugal]]

File:Spiaggia rosa, isola di budelli, sardegna.jpg, Italy. Budelli beach is famous for the color of its sand, which is pink due to the presence of fragments of a microorganism called Miniacina miniacea.{{cite web|url=https://www.sardegnaturismo.it/it/esplora/spiaggia-rosa|title=Spiaggia Rosa|date=20 November 2015 |access-date=27 December 2024|language=it}}]]

Tides often determine the range over which sediment is deposited or eroded. Areas with high tidal ranges allow waves to reach farther up the shore, and areas with lower tidal ranges produce deposition at a smaller elevation interval. The tidal range is influenced by the size and shape of the coastline. Tides do not typically cause erosion by themselves; however, tidal bores can erode as the waves surge up the river estuaries from the ocean.{{Cite book|last=Davidson|first=Jon P.|title=Exploring earth: an introduction to physical geology|date=2002|publisher=Prentice Hall|others=Walter E. Reed, Paul M. Davis|isbn=0-13-018372-5|edition=2nd|location=Upper Saddle River, NJ|oclc=45917172}}{{rp|421}}

Geologists classify coasts on the basis of tidal range into macrotidal coasts with a tidal range greater than {{Convert|4|m|ft|abbr=on}}; mesotidal coasts with a tidal range of {{Convert|2 to 4|m|ft|abbr=on|sigfig=2}}; and microtidal coasts with a tidal range of less than {{Convert|2|m|ft|abbr=on|sigfig=1}}. The distinction between macrotidal and mesotidal coasts is more important. Macrotidal coasts lack barrier islands and lagoons, and are characterized by funnel-shaped estuaries containing sand ridges aligned with tidal currents. Wave action is much more important for determining bedforms of sediments deposited along mesotidal and microtidal coasts than in macrotidal coasts.{{cite book |last1=Blatt |first1=Harvey |last2=Middleton |first2=Gerard |last3=Murray |first3=Raymond |title=Origin of sedimentary rocks |date=1980 |publisher=Prentice-Hall |location=Englewood Cliffs, N.J. |isbn=0-13-642710-3 |edition=2d |pages=656–659}}

Waves erode coastline as they break on shore releasing their energy; the larger the wave the more energy it releases and the more sediment it moves. Coastlines with longer shores have more room for the waves to disperse their energy, while coasts with cliffs and short shore faces give little room for the wave energy to be dispersed. In these areas, the wave energy breaking against the cliffs is higher, and air and water are compressed into cracks in the rock, forcing the rock apart, breaking it down. Sediment deposited by waves comes from eroded cliff faces and is moved along the coastline by the waves. This forms an abrasion or cliffed coast.

Sediment deposited by rivers is the dominant influence on the amount of sediment located in the case of coastlines that have estuaries.{{Cite book|last=Easterbrook|first=Don J.|title=Surface processes and landforms|date=1999|publisher=Prentice Hall|isbn=0-13-860958-6|edition=2nd|location=Upper Saddle River, N.J.|oclc=39890526}} Today, riverine deposition at the coast is often blocked by dams and other human regulatory devices, which remove the sediment from the stream by causing it to be deposited inland. Coral reefs are a provider of sediment for coastlines of tropical islands.{{Cite web|title=How is beach sand created? - Woods Hole Oceanographic Institution|url=https://www.whoi.edu/how-is-beach-sand-created/|url-status=live|access-date=2021-08-10|website=Woods Hole Oceanographic Institution|language=|archive-url=https://web.archive.org/web/20210628213754/https://www.whoi.edu/how-is-beach-sand-created/ |archive-date=2021-06-28 }}

Like the ocean which shapes them, coasts are a dynamic environment with constant change. The Earth's natural processes, particularly sea level rises, 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).

{{Further|Port|island nation|Coastal management|Coastal development hazards}}

File:The CHW system.png

More and more of the world's people live in coastal regions.{{Cite journal |last=Goudarzi |first=Sara |date=July 18, 2006 |title=Flocking to the Coast: World's Population Migrating into Danger |url=http://www.livescience.com/environment/060718_map_settle.html |journal=Live Science |access-date=2008-12-14}} According to a United Nations atlas, 44% of all people live within 150 km (93 mi) of the sea. Many major cities are on or near good harbors and have port facilities. Some landlocked places have achieved port status by building canals.

Nations defend their coasts against military invaders, smugglers and illegal migrants. Fixed coastal defenses have long been erected in many nations, and coastal countries typically have a navy and some form of coast guard.

File:花蓮新社梯田.jpg|Paddy fields by the coast of Fengbin, Hualien

File:170209 219 R.jpg|Coastline of Barcelona as viewed from Port Fòrum, with Montjuïc and Port Vell can also be seen.

Coasts, especially those with beaches and warm water, attract tourists often leading to the development of seaside resort communities. In many island nations such as those of the Mediterranean, South Pacific Ocean and Caribbean, tourism is central to the economy. Coasts offer recreational activities such as swimming, fishing, surfing, boating, and sunbathing.

Growth management and coastal management can be a challenge for coastal local authorities who often struggle to provide the infrastructure required by new residents, and poor management practices of construction often leave these communities and infrastructure vulnerable to processes like coastal erosion and sea level rise. In many of these communities, management practices such as beach nourishment or when the coastal infrastructure is no longer financially sustainable, managed retreat to remove communities from the coast.

File:Maarianhamina SNV10312 -2B.jpg| A passenger car ferry arrives at the coast of Mariehamn, Åland.

File:Amalfi Coast (Italy, October 2020) - 75 (50558355441).jpg|Amalfi Coast, Italy, attracts international tourists of all classes annually{{cite web |title = Bay of Naples & Amalfi Coast History |url = http://www.uniquecostiera.com/naplesAmalfiCoastHistory.html |work = Unique Costiera |access-date = 28 June 2011 |url-status = dead |archive-url = https://web.archive.org/web/20111031120459/http://www.uniquecostiera.com/naplesAmalfiCoastHistory.html |archive-date = 31 October 2011 }} and is listed as a UNESCO World Heritage Site.{{cite web |title = Costiera Amalfitana |url = https://whc.unesco.org/en/list/830 |publisher = UNESCO World Heritage Centre |access-date = 14 September 2015}}

{{see also|Marine coastal ecosystem}}

{{Excerpt|Ecosystem service#Estuarine and coastal ecosystem services|paragraphs=1,2}}

{{further information|Emergent coastline|Submergent coastline}}

According to one principle of classification, an emergent coastline is a coastline that 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. In contrast, a submergent coastline is one where the sea level has risen, 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

{{further information|Concordant coastline|Discordant coastline}}

According to the second principle of classification, a concordant coastline is a coastline where bands of different rock types run parallel to the shore. These rock types are usually of varying resistance, so the coastline forms distinctive landforms, such as coves. Discordant coastlines feature distinctive landforms because the rocks are eroded by the ocean waves. The less resistant rocks erode faster, creating inlets or bay; the more resistant rocks erode more slowly, remaining as headlands or outcroppings.

Parts of a coastline can be categorised as high energy coast or low energy coast. The distinguishing characteristics of a high energy coast are that the average wave energy is relatively high so that erosion of small grained material tends to exceed deposition, and consequently landforms like cliffs, headlands and wave-cut terraces develop. Low energy coasts are generally sheltered from waves, or in regions where the average wind wave and swell conditions are relatively mild. Low energy coasts typically change slowly, and tend to be depositional environments.

High energy coasts are exposed to the direct impact of waves and storms, and are generally erosional environments. High energy storm events can make large changes to a coastline, and can move significant amounts of sediment over a short period, sometimes changing a shoreline configuration.

Swash is the shoreward flow after the break, backwash is the water flow back down the beach. The relative strength of flow in the swash and backwash determines what size grains are deposited or eroded. This is dependent on how the wave breaks and the slope of the shore.

Depending on the form of the breaking wave, its energy can carry granular material up the beach and deposit it, or erode it by carrying more material down the slope than up it. Steep waves that are close together and break with the surf plunging down onto the shore slope expend much of their energy lifting the sediment. The weak swash does not carry it far up the slope, and the strong backwash carries it further down the slope, where it either settles in deeper water or is carried along the shore by a longshore current induced by an angled approach of the wave-front to the shore. These waves which erode the beach are called destructive waves.

Low waves that are further apart and break by spilling, expend more of their energy in the swash which carries particles up the beach, leaving less energy for the backwash to transport them downslope, with a net constrictive influence on the beach.

File:Cinque Terre (Italy, October 2020) - 11 (50543748322).jpg, along the Italian Riviera]]

Riviera is an Italian word for "shoreline",{{Cite encyclopedia|title=riviera |encyclopedia=Chambers Concise Dictionary |year=2004 |publisher=Allied Chambers |location=New Delhi |page=[https://books.google.com/books?id=iwWuY9tAVq8C&pg=PA1045 1045] |isbn = 978-81-86062-36-4}}{{Cite book|first=Martina |last=Kolb |year=2013 |title=Nietzsche, Freud, Benn, and the Azure Spell of Liguria |location=Toronto, Ontario |publisher=University of Toronto Press |page=[https://books.google.com/books?id=I03va9L2GuoC&pg=PA30 30] |isbn=978-1-4426-4329-1 }}The more common ones are puntellare and litorale. ultimately derived from Latin {{Lang|la|ripa}} ("riverbank"). It came to be applied as a proper name to the coast of the Ligurian Sea, in the form riviera ligure, then shortened to riviera. Historically, the Ligurian Riviera extended from Capo Corvo (Punta Bianca) south of Genoa, north and west into what is now French territory past Monaco and sometimes as far as Marseille.{{Cite book |first=Rosa |last=Baughan |year=1880 |title=Winter havens in the sunny South, a complete handbook to the Riviera |location=London |publisher=The Bazaar |url=https://books.google.com/books?id=zg8IAAAAQAAJ |url-status=live |archive-url=https://web.archive.org/web/20170202104650/https://books.google.com/books?id=zg8IAAAAQAAJ |archive-date=2017-02-02 }}{{Cite book |first=Charles B. |last=Black |year=1887 |title=The Riviera, Or The Coast from Marseilles to Leghorn, Including Carrara, Lucca, Pisa, Pistoja and Florence |edition=Third |location=Edinburgh |publisher=Adam and Charles Black |url=https://books.google.com/books?id=KKsaAAAAYAAJ |url-status=live |archive-url=https://web.archive.org/web/20170202213756/https://books.google.com/books?id=KKsaAAAAYAAJ |archive-date=2017-02-02 }} Today, this coast is divided into the Italian Riviera and the French Riviera, although the French use the term "Riviera" to refer to the Italian Riviera and call the French portion the "Côte d'Azur".

As a result of the fame of the Ligurian rivieras, the term came into English to refer to any shoreline, especially one that is sunny, topographically diverse and popular with tourists. Such places using the term include the Australian Riviera in Queensland and the Turkish Riviera along the Aegean Sea.

• A cliffed coast or abrasion coast is one where marine action has produced steep declivities known as cliffs.
• A flat coast is one where the land gradually descends into the sea.
• A graded shoreline is one where wind and water action has produced a flat and straight coastline.
• A primary coast isone which is mainly undergoing early stage development by major long-term processes such as tectonism and climate change A secondary coast is one where the primary processes have mostly stabilised, and more localised processes have become prominent.
• An erosional coast is on average undergoing erosion, while a depositional coast is accumulating material.
• An active coast is on the edge of a tectonic plate, while a passive coast is usually on a substantial continental shelf or away from a plate edge.

The following articles describe some coastal landforms:

File:Accreting coast Image6.svg would, in certain (mainly southern) parts of Britain, be called a cove. That between the cuspate foreland and the tombolo is a British bay.]]

{{div col|colwidth=24em}}

• Barrier island
• Bay
• Cove
• Headland
• Peninsula

{{div col end}}

• Much of the sediment deposited along a coast is the result of erosion of a surrounding cliff, or bluff. Sea cliffs retreat landward because of the constant undercutting of slopes by waves. If the slope/cliff being undercut is made of unconsolidated sediment it will erode at a much faster rate than a cliff made of bedrock.
• A natural arch is formed when a headland is eroded through by waves.
• Sea caves are made when certain rock beds are more susceptible to erosion than the surrounding rock beds because of different areas of weakness. These areas are eroded at a faster pace creating a hole or crevice that, through time, by means of wave action and erosion, becomes a cave.
• A stack is formed when a headland is eroded away by wave and wind action or an arch collapses leaving an offshore remnant.
• A stump is a shortened sea stack that has been eroded away or fallen because of instability.
• Wave-cut notches are caused by the undercutting of overhanging slopes which leads to increased stress on cliff material and a greater probability that the slope material will fall. The fallen debris accumulates at the bottom of the cliff and is eventually removed by waves.
• A wave-cut platform forms after erosion and retreat of a sea cliff has been occurring for a long time. Gently sloping wave-cut platforms develop early on in the first stages of cliff retreat. Later, the length of the platform decreases because the waves lose their energy as they break further offshore.{{clarify|what makes the platform get shorter?|date=April 2024}}

{{Div col|colwidth=24em}}

• Beach
• Beach cusps
• Cuspate foreland
• Dune system
• Mudflat
• Raised beach
• Ria
• Shoal
• Spit
• Strand plain
• Surge channel
• Tombolo

{{div col end}}

• Estuary
• Lagoon
• Salt marsh
• Mangrove forests
• Kelp forests
• Coral reefs
• Oyster reefs

{{Div col|colwidth=24em}}

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

{{div col end}}

{{See also|Eutrophication#Coastal waters}}

File:Transport of carbon across territorial boundaries in territorial sea, Exclusive Economic Zone, continental shelf, high seas, and deep seabed.webp, Exclusive Economic Zone (EEZ), continental shelf, high seas (international waters), and deep seabed.]]

"Coastal waters" (or "coastal seas") is a term that carries different meanings depending upon the context, ranging from a geographic reference to the waters within a few kilometers of the coast, to describing the entire continental shelf that may stretch for more than a hundred kilometers from land.{{Cite book |title=Ocean margin processes in global change: report of the Dahlem Workshop on Ocean Margin Processes in Global Change, Berlin, 1990, March 18-23 |date=1991 |publisher=Wiley |isbn=978-0-471-92673-3 |editor-last=Mantoura |editor-first=R. F. C |location=Chichester, New York |language=en |oclc=22765791 |editor-last2=Martin |editor-first2=Jean-Marie |editor-last3=Wollast |editor-first3=R }} The term is used in a different manner when describing legal and economic boundaries, such as territorial waters{{cite book |last1=Black |first1=Henry Campbell |last2=Garner |first2=Bryan Andrew |title=Black's law dictionary |date=2009 |publisher=West |location=St. Paul, Minn |isbn=978-0314199492 |page=729 |edition=9th}} and international waters,{{cite book |last1=Black |first1=Henry Campbell |last2=Garner |first2=Bryan Andrew |title=Black's law dictionary |date=2009 |publisher=West |location=St. Paul, Minn |isbn=978-0314199492 |page=1128 |edition=9th}} (defining "navigable sea") or when describing the geography of coastal landforms or the ecological systems operating through the continental shelf (marine coastal ecosystems).

The dynamic fluid nature of the ocean means that all components of the whole ocean system are ultimately connected, although certain regional classifications are useful and relevant. The waters of the continental shelves represent such a region.{{Cite book |last1=Simpson |first1=John H. |url=https://www.cambridge.org/core/books/introduction-to-the-physical-and-biological-oceanography-of-shelf-seas/D28A42640D9F3D5BADB6D9533D663ECD |title=Introduction to the Physical and Biological Oceanography of Shelf Seas |last2=Sharples |first2=Jonathan |publisher=Cambridge University Press |year=2012 |doi=10.1017/CBO9781139034098 |isbn=978-0-521-87762-6 |edition=1}} The term "coastal waters" has been used in a wide variety of different ways in different contexts. In European Union environmental management it extends from the coast to just a few nautical miles{{Cite web |title=coastal waters — European Environment Agency |url=https://www.eea.europa.eu/help/glossary/eea-glossary/coastal-waters |access-date=2022-06-29 |website=www.eea.europa.eu |language=en}} while in the United States the US EPA considers this region to extend much further offshore.{{Cite web |last=US EPA |first=ORD |date=2017-11-02 |title=Coastal Waters |url=https://www.epa.gov/report-environment/coastal-waters |access-date=2022-06-29 |website=www.epa.gov |language=en}}USEPA (2001) [https://www.epa.gov/sites/default/files/2018-10/documents/nutrient-criteria-manual-estuarine-coastal.pdf Nutrient Criteria Technical Guidance Manual, Estuarine and Coastal Marine Waters], U.S. Environmental Protection Agency

"Coastal waters" has specific meanings in the context of commercial coastal shipping, and somewhat different meanings in the context of naval littoral warfare.{{citation needed|date=June 2022}} Oceanographers and marine biologists have yet other takes. Coastal waters have a wide range of marine habitats from enclosed estuaries to the open waters of the continental shelf.

Similarly, the term littoral zone has no single definition. It is the part of a sea, lake, or river that is close to the shore.{{Cite journal |last1=Seekell |first1=D. |last2=Cael |first2=B. |last3=Norman |first3=S. |last4=Byström |first4=P. |year=2021 |title=Patterns and variation of littoral habitat size among lakes |journal=Geophysical Research Letters |language=en |volume=48 |issue=20 |pages=e2021GL095046 |bibcode=2021GeoRL..4895046S |doi=10.1029/2021GL095046 |issn=1944-8007 |s2cid=244253181|doi-access=free }} In coastal environments, the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged.

Coastal waters can be threatened by coastal eutrophication and harmful algal blooms.{{Cite journal |last1=Maúre |first1=Elígio de Raús |last2=Terauchi |first2=Genki |last3=Ishizaka |first3=Joji |last4=Clinton |first4=Nicholas |last5=DeWitt |first5=Michael |date=2021 |title=Globally consistent assessment of coastal eutrophication |journal=Nature Communications |language=en |volume=12 |issue=1 |page=6142 |doi=10.1038/s41467-021-26391-9 |issn=2041-1723 |pmc=8536747 |pmid=34686688}}{{Cite journal |last=Jickells |first=T. D. |date=1998 |title=Nutrient Biogeochemistry of the Coastal Zone |url=https://www.science.org/doi/10.1126/science.281.5374.217 |journal=Science |language=en |volume=281 |issue=5374 |pages=217–222 |doi=10.1126/science.281.5374.217 |issn=0036-8075 |pmid=9660744}}{{Cite journal |last1=Glibert |first1=Patricia |last2=Burford |first2=Michele |date=2017 |title=Globally Changing Nutrient Loads and Harmful Algal Blooms: Recent Advances, New Paradigms, and Continuing Challenges |url=https://tos.org/oceanography/article/globally-changing-nutrient-loads-and-harmful-algal-blooms-recent-advances-n |journal=Oceanography |volume=30 |issue=1 |pages=58–69 |doi=10.5670/oceanog.2017.110|doi-access=free |bibcode=2017Ocgpy..30a..58G |hdl=10072/377577 |hdl-access=free }}

The identification of bodies of rock formed from sediments deposited in shoreline and nearshore environments (shoreline and nearshore facies) is extremely important to geologists. These provide vital clues for reconstructing the geography of ancient continents (paleogeography). The locations of these beds show the extent of ancient seas at particular points in geological time, and provide clues to the magnitudes of tides in the distant past.{{cite book |last1=Leeder |first1=M. R. |title=Sedimentology and sedimentary basins: from turbulence to tectonics |date=2011 |publisher=Wiley-Blackwell |location=Chichester, West Sussex, UK |isbn=978-1-4051-7783-2 |edition=2nd |pages=436–437}}

Sediments deposited in the shoreface are preserved as lenses of sandstone in which the upper part of the sandstone is coarser than the lower part (a coarsening upwards sequence). Geologists refer to these are parasequences. Each records an episode of retreat of the ocean from the shoreline over a period of 10,000 to 1,000,000 years. These often show laminations reflecting various kinds of tidal cycles.

Some of the best-studied shoreline deposits in the world are found along the former western shore of the Western Interior Seaway, a shallow sea that flooded central North America during the late Cretaceous Period (about 100 to 66 million years ago). These are beautifully exposed along the Book Cliffs of Utah and Colorado.{{sfn|Blatt|Middleton|Murray|1980|pp=673-674}}

The following articles describe the various geologic processes that affect a coastal zone:

{{Div col|colwidth=24em}}

• Attrition
• Currents
• Denudation
• Deposition
• Erosion
• Flooding
• Longshore drift
• Marine sediments
• Saltation
• Sea level change
• eustatic
• isostatic
• Sedimentation
• Coastal sediment supply
• sediment transport
• solution
• subaerial processes
• suspension
• Tides
• Water waves
• diffraction
• refraction
• wave breaking
• wave shoaling
• Weathering

{{div col end}}

{{see also|Coastal ecology|Marine coastal ecosystem}}

{{See also|Seashore wildlife}}

{{Unsourced section|date=April 2018}}

Larger animals that live in coastal areas include puffins, sea turtles and rockhopper penguins, among many others. Sea snails and various kinds of barnacles live on rocky coasts and scavenge on food deposited by the sea. Some 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, including sessile animals such as corals, sponges, starfish, mussels, seaweeds, fishes, and sea anemones.

There are many kinds of seabirds on various coasts. These include pelicans and cormorants, who join up with terns and oystercatchers to forage for fish and shellfish. There are sea lions on the coast of Wales and other countries.

{{excerpt|Coastal fish}}

Many coastal areas are famous for their kelp beds. Kelp is a fast-growing seaweed that can grow up to half a meter a day in ideal conditions. Mangroves, seagrasses, macroalgal beds, and salt marsh are important coastal vegetation types in tropical and temperate environments respectively. Restinga is another type of coastal vegetation.

{{see also|Coastal development hazards|marine coastal ecosystem}}

Coasts also face many human-induced environmental impacts and coastal development hazards. The most important ones are:

• Pollution which can be in the form of water pollution, nutrient pollution (leading to coastal eutrophication and harmful algal blooms), oil spills or marine debris that is contaminating coasts with plastic and other trash.
• Sea level rise, and associated issues like coastal erosion and saltwater intrusion.

{{See also|Human impact on marine life}}

File:Marbleheadcoastline.jpg. Once a fishing port, the harbor is now dedicated to tourism and pleasure boating. Observe that the sand and rocks have been darkened by oil slick up to the high-water line.]]

File:Beach at Msasani Bay, Dar es Salaam, Tanzania.JPG

File:Aquatic Dead Zones.jpg occur when phosphorus and nitrogen from fertilizers cause excessive growth of microorganisms, which depletes oxygen and kills fauna.]]

The pollution of coastlines is connected to marine pollution which can occur from a number of sources: Marine debris (garbage and industrial debris); the transportation of petroleum in tankers, increasing the probability of large oil spills; small oil spills created by large and small vessels, which flush bilge water into the ocean.

{{excerpt|Marine pollution|paragraphs=1-2|file=no}}

{{excerpt|Marine debris|paragraphs=1-2|file=no}}

{{excerpt|Plastic soup#Microplastics|paragraphs=1-2|file=no}}

{{Excerpt|Sea level rise|paragraphs=1-2|file=no}}

International attention to address the threats of coasts has been captured in Sustainable Development Goal 14 "Life Below Water" which sets goals for international policy focused on preserving marine coastal ecosystems and supporting more sustainable economic practices for coastal communities. Likewise, the United Nations has declared 2021–2030 the UN Decade on Ecosystem Restoration, but restoration of coastal ecosystems has received insufficient attention.

{{portal|Geography|Oceans}}

• Bank (geography)
• Beach cleaning
• Coastal and Estuarine Research Federation
• European Atlas of the Seas
• Intertidal zone
• Land reclamation
• List of countries by length of coastline
• List of U.S. states by coastline
• Offshore or Intertidal zone
• Ballantine Scale
• Coastal path
• Shorezone

{{reflist|refs=

{{cite web |url=https://www.bbc.co.uk/bitesize/guides/zt6r82p/revision/1 |title=Coastal processes - AQA, Wave types - constructive and destructive |website=www.bbc.co.uk |access-date=13 April 2024 }}

{{cite web |url=https://www.field-studies-council.org/resources/16-18-geography/coasts/high-energy-coasts/ |title=High energy coasts |website=www.field-studies-council.org |access-date=13 April 2024 }}

{{cite web |url=https://www.field-studies-council.org/resources/16-18-geography/coasts/high-energy-coasts/method/ |title=Method for high energy coasts |website=www.field-studies-council.org |access-date=13 April 2024 }}

{{cite journal|last1=Guisado-Pintado |first1=E |last2=Jackson |first2=D.W.T. |date=2019|title=Coastal Impact From High-Energy Events and the Importance of Concurrent Forcing Parameters: The Cases of Storm Ophelia (2017) and Storm Hector (2018) in NW Ireland. |journal=Front. Earth Sci. |volume=7 |issue=190 |doi=10.3389/feart.2019.00190 |doi-access=free |bibcode=2019FrEaS...7..190G }}

{{cite web |url=https://www.vaia.com/en-us/explanations/geography/coasts-geography/classification-of-coasts/ |title=Classification of Coasts |website=www.vaia.com |accessdate=13 April 2024 }}

}}

• {{cite book

|last1=Scheffers|first1=Anja M.

|last2=Scheffers|first2=Sander R.

|last3=Kelletat|first3=Dieter H.

|title=The Coastlines of the World with Google Earth: Understanding our Environment

|date=2012

|publisher=Springer

|location=New York

|isbn=978-94-007-0737-5}}

• [https://www.whoi.edu/ Woods Hole Oceanographic Institution] - organization dedicated to ocean research, exploration, and education

{{Commons category|Coasts}}

{{Wikiquote}}

{{Wiktionary|coast}}

{{Wikiversity}}

{{Coastal geography}}{{Vegetation}}{{Authority control}}

Category:Coastal and oceanic landforms

Category:Coastal geography

Category:Oceanographical terminology

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