Fjord



In, a or   is a long, narrow  with steep sides or cliffs, created by a. There are many fjords on the coasts of and. is estimated to be 29000 km long with its nearly 1,200 fjords, but only 2500 km long.

Formation
A true fjord is formed when a cuts a  by  and  of the surrounding bedrock. According to the standard model, glaciers formed in pre-glacial valleys with a gently sloping valley floor. The work of the glacier then left an  that ends abruptly at a valley or trough end. Such valleys are fjords when flooded by the ocean. Thresholds above sea level create freshwater lakes. Glacial melting is accompanied by the rebounding of Earth’s crust as the ice load and eroded sediment is removed (also called or glacial rebound). In some cases this rebound is faster than. Most fjords are. Fjords generally have a sill or shoal (bedrock) at their mouth caused by the previous glacier’s reduced erosion rate and. In many cases this sill causes extreme currents and large saltwater rapids (see ). in Norway is often described as the world’s strongest. These characteristics distinguish fjords from (e.g. the ), which are drowned valleys flooded by the rising sea. is cut almost in two by the “ridge”, a sandy moraine that during the ice cover was under sea level but after the post-glacial rebound reaches 60 m above the fjord.

Thresholds at the mouths and overdeepening of fjords compared to the ocean are the strongest evidence of glacial origin, and these thresholds are mostly rocky. Thresholds are related to sounds and low land where the ice could spread out and therefore have less erosive force. In the case of Hardangerfjord the fractures of the has guided the erosion by glaciers, while there is no clear relation between the direction of Sognefjord and the fold pattern. This relationship between fractures and direction of fjords is also observed in. Preglacial, rivers presumably eroded the surface and created valleys that later guided the glacial flow and erosion of the bedrock. This may in particular have been the case in Western Norway where the tertiary uplift of the landmass amplified eroding forces of rivers.

Confluence of tributary fjords led to excavation of the deepest fjord basins. Near the very coast the typical West Norwegian glacier spread out (presumably through sounds and low valleys) and lost their concentration and reduced the glaciers' power to erode leaving bedrock thresholds. is 160 m deep with a threshold of only 1.5 m, while the 1300 m deep Sognefjorden has a threshold around 100 to 200 m deep. is made up of several basins separated by thresholds: The deepest basin Samlafjorden between Jonaneset and  with a distinct threshold at Vikingneset in.

are common along glaciated fjords and. A hanging valley is a valley that is higher than the main valley and was created by tributary  flows into a glacier of larger volume. The shallower valley appears to be ‘hanging’ above the main valley or a fjord. Often, form at or near the outlet of the upper valley. Small waterfalls within these fjords are also used as freshwater resources. Hanging valleys also occur under water in fjord systems. The branches of are for instance much shallower than the main fjord. The mouth of is about 400 m deep while the main fjord is 1200 m nearby. The mouth of Ikjefjord is only 50 meters deep while the main fjord is around 1300 m at the same point.

Hydrology
During the winter season there is usually little inflow of freshwater. Surface water and deeper water (down to 100 m or more) are mixed during winter because of the steady cooling of the surface and wind. In the deep fjords there is still fresh water from the summer with less density than the saltier water along the coast. Offshore wind, common in the fjord areas during winter, sets up a current on the surface from the inner to the outer parts. This current on the surface in turn pulls dense salt water from the coast across the fjord threshold and into the deepest parts of the fjord. Bolstadfjorden has a threshold of only 1.5 m and strong inflow of freshwater from river creates a brackish surface that blocks circulation of the deep fjord. The deeper, salt layers of Bolstadfjorden are deprived of oxygen and the seabed is covered with organic material. The shallow threshold also creates a strong tidal current.

During the summer season there is usually a large inflow of river water in the inner areas. This freshwater gets mixed with saltwater creating a layer of brackish water with a slightly higher surface than the ocean which in turn sets up a current from the river mouths towards the ocean. This current is gradually more salty towards the coast and right under the surface current there is a reverse current of saltier water from the coast. In the deeper parts of the fjord the cold water remaining from winter is still and separated from the atmosphere by the brackish top layer. This deep water is ventilated by mixing with the upper layer causing it to warm and freshen over the summer. In fjords with a shallow threshold or low levels of mixing this deep water is not replaced every year and low oxygen concentration makes the deep water unsuitable for fish and animals. In the most extreme cases there is a constant barrier of freshwater on the surface and the fjord freezes over such that there is no oxygen below the surface. is one example. The mixing in fjords predominantly results from the propagation of an from the entrance sill or internal seiching.

The Gaupnefjorden branch of is strongly affected by freshwater as a glacial river flows in. has little inflow of freshwater.

Coral reefs
In 2000, some were discovered along the bottoms of the Norwegian fjords. These reefs were found in fjords from the north of Norway to the south. The marine life on the reefs is believed to be one of the most important reasons why the Norwegian coastline is such a generous fishing ground. Since this discovery is fairly new, little research has been done. The reefs are host to thousands of lifeforms such as, , , fish, several species of shark, and many more. Most are specially adapted to life under the greater pressure of the above it, and the total darkness of the deep sea.

New Zealand’s fjords are also host to, but a surface layer of dark fresh water allows these corals to grow in much shallower water than usual. An underwater observatory in allows tourists to view them without diving.

Skerries
In some places near the seaward margins of areas with fjords, the ice-scoured channels are so numerous and varied in direction that the rocky coast is divided into thousands of island blocks, some large and mountainous while others are merely rocky points or rock s, menacing navigation. These are called. The term skerry is derived from the sker, which means a rock in the sea.

Skerries most commonly formed at the outlet of fjords where submerged glacially formed valleys perpendicular to the coast join with other cross valleys in a complex array. The island fringe of Norway is such a group of skerries (called a skjærgård); many of the cross fjords are so arranged that they parallel the coast and provide a protected channel behind an almost unbroken succession of mountainous islands and skerries. By this channel one can travel through a protected passage almost the entire 1601 km route from to, Norway. The is a skerry-protected waterway that starts near  in southern Norway, and continues past. The coast along  is likewise skerry guarded. The provides a similar route from, , and , , to ,. Yet another such skerry protected passage extends from the north for 800 km.

Phytoplankton
Fjords provide unique environmental conditions for communities. In polar fjords, glacier and ice sheet outflow add cold, fresh meltwater along with transported sediment into the body of water. Nutrients provided by this outflow can significantly enhance phytoplankton growth. For example, in some fjords of the West Antarctic Peninsula (WAP), nutrient enrichment from meltwater drives blooms, a highly productive group of phytoplankton that enable such fjords to be valuable feeding grounds for other species. It is possible that as reduces long-term meltwater output, nutrient dynamics within such fjords will shift to favor less productive species, destabilizing the food web ecology of fjord systems.

In addition to nutrient flux, sediment carried by flowing glaciers can become suspended in the water column, increasing and reducing light penetration into greater depths of the fjord. This effect can limit the available light for in deeper areas of the water mass, reducing phytoplankton abundance beneath the surface.

Overall, phytoplankton abundance and species composition within fjords is highly seasonal, varying as a result of seasonal light availability and water properties that depend on glacial melt and the formation of sea ice. The study of phytoplankton communities within fjords is an active area of research, supported by groups such as FjordPhyto, a citizen science initiative to study phytoplankton samples collected by local residents, tourists, and boaters of all backgrounds.

Epishelf lakes
An epishelf lake forms when meltwater is trapped behind a floating ice shelf and the freshwater floats on the denser saltwater below. Its surface may freeze forming an isolated ecosystem.

Etymology


The word fjord is borrowed from, where it is pronounced , , or  in various  and has a more general meaning, referring in many cases to any long, narrow body of water,  or  (for example, see ).

The Norwegian word is inherited from fjǫrðr, a noun which refers to a ‘lake-like’ body of water used for passage and ferrying and is closely related to the noun ferð “travelling, ferrying, journey”. Both words go back to  “crossing”, from the root  "cross". The words fare and ferry are of the same origin.

The Scandinavian fjord, *ferþuz, is the origin for similar  words:  fjörður,  fjørður,  fjärd (for Baltic waterbodies),  . The Norse noun fjǫrðr was adopted in German as Förde, used for the narrow long bays of, and in English as firth “fjord, river mouth”. The English word ' (compare Furt,  Ford or Vörde, in  names voorde such as Vilvoorde,  πόρος, poros, and  portus) is assumed to originate from Germanic ferþu- and Indo-European root *' meaning "crossing point". Fjord/firth/Förde as well as ford/Furt/Vörde/voorde refer to a Germanic noun for a travel: ferd or färd and of the verb to travel, Dutch varen, German fahren; English to fare.

As a from Norwegian, it is one of the few words in the English language to start with the sequence fj. The word was for a long time normally spelled fiord, a spelling preserved in place names such as. The fiord spelling mostly remains only in, as in the place name.

Scandinavian usage


The use of the word fjord in Norwegian, Danish and Swedish is more general than in English and in international scientific terminology. In Scandinavia, fjord is used for a narrow inlet of the sea in Norway, Denmark and western Sweden, but this is not its only application. In Norway and Iceland, the usage is closest to the Old Norse, with fjord used for both a firth and for a long, narrow inlet. In eastern Norway, the term is also applied to long narrow freshwater lakes ( and ) and sometimes even to rivers (for instance in in, the  is referred to as fjorden). In southeast Sweden, the name fjärd is a subdivision of the term ‘fjord’ used for bays,  and narrow inlets on the Swedish  coast, and in most Swedish lakes. This latter term is also used for bodies of water off the coast of Finland where is spoken. In Danish, the word may even apply to shallow. In modern Icelandic, fjörður is still used with the broader meaning of firth or inlet. In fjørður is used both about inlets and about broader sounds, whereas a narrower sound is called sund. In the, a word vuono is used although there is only one fjord in Finland.

In old Norse was fjarðar whereas  was firði. The dative form has become common place names like Førde (for instance ), Fyrde or Førre (for instance ).

The German use of the word Föhrde for long narrow bays on their Baltic Sea coastline, indicates a common origin of the word. The landscape consists mainly of moraine heaps. The Föhrden and some “fjords” on the east side of Jutland, Denmark are also of glacial origin. But while the glaciers digging “real” fjords moved from the mountains to the sea, in Denmark and Germany they were tongues of a huge glacier covering the basin of which is now the Baltic Sea. See.

Whereas fjord names mostly describe bays (though not always geological fjords), in the same regions typically are named Sund, in Scandinavian languages as well as in German. The word is related to “to sunder” in the meaning of “to separate”. So the use of  to name fjords in North America and New Zealand differs from the European meaning of that word.

The name of in  is originally derived from Veisafjǫrðr (“inlet of the mud flats”) in Old Norse, as used by the  settlers—though the inlet at that place in modern terms is an, not a fjord.

Before or in the early phase of angr was another  for fjords and other inlets of the ocean. This word has survived only as a suffix in names of some Scandinavian fjords and has in same cases also been transferred to adjacent settlements or surrounding areas for instance, and.

Differences in definitions


The differences in usage between the and the  have contributed to confusion in the use of the term fjord. Bodies of water that are clearly fjords in Scandinavian languages are not considered fjords in English; similarly bodies of water that would clearly not be fjords in the Scandinavian sense have been named or suggested to be fjords. Examples of this confused usage follow.

In the some inlets are called a fjord, but are technically not a fjord. For example, Roskilde Fjord. in English terminology is a, since it separates the (Vendsyssel-Thy) from the rest of. However, the Limfjord once was a fjord until the sea broke through from the west. on the western coast of is a. The long narrow fjords of Denmark’s coast like the German  were dug by ice moving from the sea upon land, while fjords in the geological sense were dug by ice moving from the mountains down to the sea. However, some definitions of a fjord is: “A long narrow inlet consisting of only one inlet created by glacial activity”. Examples of Danish fjords are:, and.

The fjords in (Norway), which are fjords in the  sense of the term, are not universally considered to be  fjords by the scientific community. Although glacially formed, most Finnmark fjords lack the steep-sided valleys of the more southerly Norwegian fjords since the glacial pack was deep enough to cover even the high grounds when they were formed. The on the other hand is a, and not glacially formed.

“Fjords” not created by glaciers
The term fjord is sometimes applied to steep-sided inlets which were not created by glaciers. Most such inlets are drowned river canyons or. Examples are
 * in {{w|Montenegro{{w|
 * the {{w|Lim (Croatia)|Lim}} bay in {{w|Istria}}, {{w|Croatia}}, is sometimes called “Lim fjord” although it is a ria dug by the river Pazinčica. The {{w|Croats}} call it {{lang|hr|Limski kanal}}, which does not translate precisely to the English equivalent either.
 * In {{w|Acapulco}}, {{w|Mexico}}, the {{w|calanque|calanques]]—narrow, rocky inlets—on the western side of the city, where the famous cliff-divers perform daily, are described in the city’s tourist literature as being fjords.
 * The {{w|Fiordo di Furore}} in Italy is a ria
 * The {{w|Khor ash Sham}} in the {{w|Musandam Peninsula}} in {{w|Oman}}, and other “khors” or inlets in the deeply indented coast of Musandam, are often described as “fjords”. They were formed by the {{w|subduction}} of the {{w|Arabian Plate|Arabian tectonic plate}} beneath the {{w|Eurasian Plate|Eurasian plate}}.

Freshwater fjords
Some Norwegian freshwater lakes that have formed in long glacially carved valleys with sill thresholds, ice front deltas or terminal blocking the outlet follow the Norwegian naming convention; they are frequently named fjords. Ice front deltas developed when the ice front was relatively stable for long time during the melting of the ice shield. The resulting landform is an between the lake and the saltwater fjord, in Norwegian called "eid" as in placename  or. The post-glacial rebound changed these deltas into terraces up to the level of the original sea level. In Eidfjord, has dug through the original delta and left a 110 m terrace while lake is only 19 m above sea level. Such deposits are valuable sources of high quality building materials (sand and gravel) for houses and infrastructure. Eidfjord village sits on the eid or isthmus between lake and Eidfjorden branch of Hardangerfjord. Nordfjordeid is the isthmus with a village between Hornindalsvatnet lake and. Such lakes are also denoted fjord valley lakes by geologists.

One of Norway's largest is at 63 m above sea level and an average depth at 97 m most of the lake is under sea level. Norway's largest lake,, is also referred to as “the fjord” by locals. Another example is the freshwater fjord (Mo lake) that until 1743 was separated from  by an isthmus and connected by a short river. During a flood in November 1743 the river bed eroded and sea water could flow into the lake at high tide. Eventually Movatnet became a saltwater fjord and renamed Mofjorden (Mofjorden). Like fjords, freshwater lakes are often deep. For instance is at least 500 m deep and water takes an average of 16 years to flow through the lake. Such lakes created by glacial action are also called fjord lakes or.

Some of these lakes were salt after the ice age but later cut off from the ocean during the. At the end of the Eastern Norway was about 200 m lower (the marine limit). When the ice cap receded and allowed the ocean to fill valleys and lowlands, and lakes like Mjøsa and Tyrifjorden were part of the ocean while Drammen valley was a narrow fjord. At the time of the  was still 4 or higher than today and reached the town of, while parts of what is now the city of  was under water. After the ice age the ocean was about 150 m at. The ocean stretched like a fjord through all the way to. eventually separated Heddalsvatnet from the ocean and turned it into a freshwater lake. In times Heddalsvatnet was still a saltwater fjord connected to the ocean, and was cut off from the ocean around 1500 BC.

Some salt water fish got trapped in lakes that originally were part of the salt fjord and gradually became freshwater fish such as the. Some freshwater fjords such as are above the marine limit.

Like freshwater fjords, the continuation of fjords on land are in the same way denoted as fjord-valleys. For instance ( valley) and. Outside of Norway, the three western arms of ’s are named North Fiord, Middle Fiord and South Fiord. Another freshwater “fjord” in a larger lake is, in ; it is also often described as a fjord, but is actually a freshwater lake cut off from the sea, so is not a fjord in the English sense of the term. Locally they refer to it as a “landlocked fjord”. Such lakes are sometimes called “fjord lakes”. was the first North American lake to be so described, in 1962. The bedrock there has been eroded up to 650 m below sea level, which is 2000 m below the surrounding regional topography. Fjord lakes are common on the inland lea of the and ; notable ones include, , , and. , and others in the basin of the  are also fjord-like in nature, and created by glaciation in the same way. Along the, a notable fjord-lake is , which is a freshwater extension of. , located in central British Columbia, is claimed to be the deepest fjord formed lake on Earth.

Great Lakes
A family of freshwater fjords are the embayments of the North American Great Lakes. Baie Fine is located on the northwestern coast of of  in, and  is located on the southern shore of  in.

Locations
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The principal mountainous regions where fjords have formed are in the higher {{w|middle latitudes}} and the high latitudes reaching to 80°N (Svalbard, Greenland), where, during the glacial period, many valley glaciers descended to the then-lower sea level. The fjords develop best in mountain ranges against which the prevailing {{w|westerlies|westerly}} marine winds are {{w|Orographic lift|orographically lifted}} over the mountainous regions, resulting in abundant snowfall to feed the glaciers. Hence coasts having the most pronounced fjords include the west coast of Norway, the west coast of North America from {{w|Puget Sound}} to Alaska, the southwest coast of New Zealand, and the west and to south-western coasts of {{w|South America}}, chiefly in {{w|Chile}}.

{{footer start}} = {{footer resources}} = {{footer |       navboxes = {{glaciers navbox}} {{coastal geography}} |       see also = {{Portal bar|Water|Environment|Geology}} |        sources = | further reading = |          notes = |     references = {{reflist|33em}} | external links = {{wiktionary}} {{commons|Fjord|Fjord}} {{Wikivoyage|Fjord}} }}
 * Firth
 * Förden and East Jutland Fjorde
 * Fjard
 * Ria
 * {{harndex-1st|page=21}}
 * {{harndex-3rd|page=49}}
 * {{harnplayer|page=89}}
 * {{cite book|last1=Moore|first1=Arthur William|title=The Surnames & Place-Names of the Isle of Man|publisher=E. Stock|isbn=978-1110309573|url=https://archive.org/details/surnamesplacena00moorgoog|page=2|quote=surnames and place-names of isle of man.|date=1890|access-date=April 24, 2015}}
 * Use of whales to probe Arctic fjord's secrets
 * Fiordland's Marine Reserves Department of Conservation
 * Nextstopnorway – Listing of Norwegian fjords{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }}
 * Saguenay River – The Canadian Atlas Online
 * {{wikipedia}}

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