View source for Øresund

{{Short description|Strait between Denmark and Sweden}}
{{Infobox body of water
| name                   = Øresund
| image                  = Map of Øresund new version.JPG
| caption                = Øresund, showing its northern and southern boundaries
| alt                    = Map of the Øresund region
| image_bathymetry       = 
| caption_bathymetry     = 
| depth                  = 
| max-depth              = {{convert|-40|m|abbr=on}}
| inflow                 =
| outflow                =
| catchment              =
| basin_countries        = [[Sweden]] and [[Denmark]]
| length                 = {{convert|118|km|abbr=on}}
| width                  = {{convert|28|km}}
| min_width              = {{convert|4|km|abbr=on}}
| islands                = 
| etymology              = 
| location               = 
| pushpin_map            = Denmark#Europe
| pushpin_label_position = 
| pushpin_map_alt        = Location of Øresund in Europe
| pushpin_map_caption    = 
| coordinates            = {{coord|55|45|N|12|45|E|type:waterbody|display=inline,title|format=dms}}
| coor_pinpoint          = 
| part_of                = 
| type                   = [[Strait]]
| cities                 = 
| area                   = 
| oceans                 = 
}}
[[File:Landskrona aerial.jpg|thumb|275px|Aerial view of Øresund and the municipality of [[Landskrona]] in Sweden]]
[[File:Øresund Bridge from the air in September 2015.jpg|thumb|275px|Øresund Bridge from the air in September 2015]]
'''Øresund''' or '''Öresund''' ({{IPAc-en|UK|ˌ|ɜːr|ə|ˈ|s|ʊ|n|d}}, {{IPAc-en|US|ˈ|ɜːr|ə|s|ʌ|n|,_|-|s|ʊ|n|d|,_|ˈ|ɔːr|ə|s|ʊ|n|d}};<ref>[https://en.oxforddictionaries.com/definition/us/øresund "Øresund"]{{dead link|date=September 2022|bot=medic}}{{cbignore|bot=medic}} (US) and {{Cite dictionary |url=http://www.lexico.com/definition/%C3%98resund |archive-url=https://web.archive.org/web/20210514164337/https://www.lexico.com/definition/%C3%98resund |url-status=dead |archive-date=2021-05-14 |title=Øresund |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]]}}</ref><ref>{{Cite Merriam-Webster|Øresund|accessdate= February 6, 2019}}</ref><ref>{{Cite American Heritage Dictionary|Øresund|accessdate= February 6, 2019}}</ref> {{langx|da|Øresund}} {{IPA|da|ˈøːɐˌsɔnˀ|}}; {{langx|sv|Öresund}} {{IPA|sv|œːrɛˈsɵnːd|}}),<ref>{{cite web|title= Bælthavet og Sundet|url= http://www.dmi.dk/dmi/baltsund|publisher= [[Danish Meteorological Institute]]|access-date= 30 March 2013|language= da|archive-date= 24 December 2018|archive-url= https://web.archive.org/web/20181224184009/http://www.dmi.dk/dmi/baltsund|url-status= dead}}</ref> commonly known in English as '''the Sound''',<ref>[https://www.britannica.com/place/The-Sound "The Sound."] ''Encyclopædia Britannica''. 12 March 2004. Retrieved 20 April 2017.</ref> is a [[strait]] which forms the [[Denmark–Sweden border|Danish–Swedish border]], separating [[Zealand]] ([[Denmark]]) from [[Scania]] ([[Sweden]]).  The strait has a length of {{convert|118|km}}; its width varies from {{convert|4|km}} to {{convert|28|km}}. The narrowest point is between [[Helsingør]] in Denmark and [[Helsingborg]] in Sweden.

Øresund, along with the [[Great Belt]], the [[Little Belt]] and the [[Kiel Canal]], is one of four waterways that connect the [[Baltic Sea]] to the [[Atlantic Ocean]] via [[Kattegat]], [[Skagerrak]], and the [[North Sea]]; this makes it one of the busiest waterways in the world.<ref>{{cite book|chapter-url= https://books.google.com/books?id=t3DXmc-mFhEC&q=%F6resund+ship+traffic&pg=PA28 |first= Henrik |last= Gluver |author2= Dan Olsen  |title= Ship Collision Analysis |chapter= 2.7 Øresund Bridge, Denmark-Sweden |year= 1998 |publisher= A. A. Balkema |location= [[Rotterdam]] |isbn= 90-5410-962-9 |quote= Øresund (the Strait) is, like the Great Belt, an important water way for the international ship traffic between the North Sea and the Baltic Sea.}}</ref>

The [[Øresund Bridge]], between the Danish capital [[Copenhagen]] and the Swedish city of [[Malmö]], inaugurated on 1 July 2000, connects a bi-national [[Øresund Region|metropolitan area]] with close to 4 million inhabitants.<ref>The region had a population of 3,894,365 {{as of | 2015 | lc = on}} and a population density of 187/km<sup>2</sup>. {{cite web|title= Geography|url= http://www.tendensoresund.org/en/geography|publisher= Tendens Øresund|access-date= 29 October 2010|archive-date= 11 February 2010|archive-url= https://web.archive.org/web/20100211095153/http://www.tendensoresund.org/en/geography|url-status= dead}}. On 1 January 2016 the Øresund Committee changed the name of the region to "Greater Copenhagen and Skåne".</ref> The [[HH Ferry route]], between [[Helsingør]], Denmark and [[Helsingborg]], Sweden, in the northern part of Øresund, is one of the world's busiest international [[ferry]] routes, with more than 70 departures from each harbour per day.<ref>{{cite web|title= At Scandlines|url= http://www.scandlines.se/tider-och-priser/tidtabell.aspx|access-date= 2015-01-09|archive-date= 2016-12-24|archive-url= https://web.archive.org/web/20161224165755/http://www.scandlines.se/tider-och-priser/tidtabell.aspx|url-status= dead}} press "Tidtabell 2 jan-31 maj 2015", PDF file.</ref>

Øresund is a [[deep time|geologically young]] strait that formed 8,500–8,000 years ago as a result of [[sea-level rise|rising sea level]]s. Previously, the [[Ancylus Lake]], a fresh-water body occupying the [[geology of the Baltic Sea|Baltic basin]], had been connected to the sea solely via the [[Great Belt]]. The incursion of salt water via Øresund marked the beginning of the modern Baltic Sea as a salt-water body.<ref name=Bjorcketal2008>{{cite book |last1= Björck |first1= Svante |last2= Andrén |first2= Thomas |last3= Jensen |first3= Jørn Bo |author-link1= Svante Björck |date= 2008 |chapter= An attempt to resolve the partly conflicting data and ideas on the ancylus-Littorina transition |chapter-url= https://www.pgi.gov.pl/en/docman-tree/publikacje-2/special-papers/23/1551-sp23-bjorck/file.html |title= Proceedings of the Workshop "Relative sea level changes" |series= Polish Geological Institute Special Papers |volume= 23 |pages= 21–26 |access-date= 2018-01-14 |archive-date= 2018-01-15 |archive-url= https://web.archive.org/web/20180115001442/https://www.pgi.gov.pl/en/docman-tree/publikacje-2/special-papers/23/1551-sp23-bjorck/file.html |url-status= dead }}</ref>

==Name==
The strait is called ''Øresund'' in [[Danish language|Danish]] (and [[Norwegian language|Norwegian]]), and ''Öresund'' in [[Swedish language|Swedish]], informally ''Sundet''<ref name=runeberg>{{Cite encyclopedia|entry-url=https://runeberg.org/nfcn/0093.html|entry=Öresund|date=1922|title=Nordisk familjebok|trans-title=Nordic Family Book|edition=Owl|volume=34|language=sv}}</ref> ({{lit|the Strait}}) in all three languages.
The first part of the name is ''[[:wikt:eyra#Old Norse|øre]]'' "gravel/sand beach", and the second part is ''[[:wikt:Appendix:Proto-Germanic/sundą|sund]]'', i.e. "sound, strait".

The name is first attested on a [[Mejlbystenen|runestone]] dated to ca. AD 1000, where it is written as ''ura suti'', read as [[Old East Norse]] {{IPA|/øːrasundi/}} (the dative case).<ref>[[Mejlbystenen]], [[Rundata|DR]] 117. {{lang|non|᛬ᛁ᛬ᚢᚱᛅ᛬ᛋᚢᛏᛁ᛬}} "in the ear-sound".</ref> 
The [[Old West Norse]] (and [[Icelandic language|modern Icelandic]]) form of the name is ''Eyrarsund''. 
''Ør'' is the modern form of the old Norse word (aur) meaning a gravel beach or shoal (see also [[Ayre (landform)|ayre]]), often forming a [[Spit (landform)|spit]]. Such landforms are common in the area and "ör" is found in the names of many places along the strait, e.g. [[Helsingør]], [[Skanör]], [[Dragør]] and [[Halör]], an important center of trade during the [[Viking Age]].<ref name=runeberg/>
<ref>''[https://ordnet.dk/ods/ordbog?query=%C3%B8re Øre]'' ''[[Ordbog over det danske Sprog]]'' "et smalt stykke land imellem to store vande, fra et land til andet. [...] Øresund kaldes saaledes fordi det begynder ved Siellands Øre og ved Øster-Søen ved et Øre, som er Skan-Øre. [...] sandet ell. gruset strand(bred), ofte spec.: dannende en odde, en halvø ell. en smal landtange."
{{cite book|first=Jan |last=Katlev |title=Politikens Etymologisk Ordbog |page=694 |year=2000 |publisher=Politikens Forlag |location=[[Copenhagen]] |isbn=87-567-6200-3 |quote=af ''ør'', ''øre'' 'gruset strandbred' + sund.}}
[https://ordnet.dk/ods/ordbog?query=%C3%B8r Ør], ''[[Ordbog over det danske Sprog]]''. Cf. also Ole Lauridsen in the Danish radio program ''Sproghjørnet'' [http://www.dr.dk/p4/sproghjoernet/sprog-uge-1509-nr-1 (audio clip in Danish)].</ref>
<ref>[https://svenska.se/so/?id=62498&pz=7 ''Svensk Ordbok''] published by the [[Swedish Academy]] "Ör: (bank av) grus eller sand [...] sedan 1000-talet [[:sv:Upplands runinskrifter 996|runsten, Funbo, Uppland (Sveriges runinskrifter)]] runform aur, fornsv. ör, sv. dial. ör ’grus, sten’"</ref>

== Boundaries ==
The northern boundary between Øresund and [[Kattegat]] is a line which goes from [[Gilleleje]] at Zealand's northern peak to the westernmost point of [[Kullaberg]] (Kullen's Lighthouse) at the smaller peninsula north of [[Helsingborg]], known as [[Kullaberg|Kullahalvön]]. In the south, the boundary towards the [[Baltic Sea]] starts at [[Stevns Klint]], at the westernmost peak of the peninsula just south of [[Køge Bay]], [[Stevns Peninsula]] to [[Falsterbo]] at the Falsterbo peninsula. 
Its eastern boundary is the Swedish coastline; to the west [[Amager]] may be considered part of Øresund (in which case it is the largest island) or a part of Zealand. Amager has eight connections with Zealand (two street bridges, a road bridge, a motorway bridge, a dual-track railway tunnel, an underground metro and a bicycle bridge) as well as a combined motorway and dual track railway to Scania and Sweden.

==Streams, animals and salinity==
Øresund, like other Danish and Danish-German straits, is at the border between oceanic salt water (which has a salinity of more than 30 [[Salinity#Seawater|PSU]] or [[per mille]] by weight) and the far less salty [[Baltic Sea]].

As the [[Kattegat]] in the north has almost oceanic conditions and the Baltic Sea (around 7 PSU, in its main basin) has [[brackish]] water, Øresund's water conditions are rather unusual and shifting. The streams are very complex, but the surface stream is often northbound (from the Baltic Sea) which gives a lower surface salinity, though streams can change from one day to another. The average surface salinity is about 10–12 PSU in the southern part, but above 20 PSU north of Helsingør.

Near the seafloor (where the sea is deep enough), conditions are more stable and salinity is always oceanic (above 30 PSU) below a certain depth that varies between 10 and 15 metres. In the southern part, however, the depth is 5–6 metres (outside the rather narrow waterways [[Drogden]] and [[Flintrännan]]), and this is the definite border of oceanic salt water, therefore also a border for many maritime species of animals. Only 52 known salt-water species reside in the central Baltic Sea, compared to around 1500 in the [[North Sea]]. Close to 600 species are known to exist in at least some part of Øresund. Well-known examples, for which the bottom salinity makes a distinct breeding border, include lobster, small crabs (''[[Carcinus maenas]]''), several species of [[flatfish]] and the [[lion's mane jellyfish]]; the latter can sometimes drift into the southwest Baltic Sea, but it cannot reproduce there.

There are daily tides, but the lunar attraction cannot force much water to move from west to east, or vice versa, in narrow waters where the current is either northbound or southbound. So, not much of the difference in water levels in Øresund is due to daily tides, and other circumstances "hide" the little tide that still remains. The current has a much stronger effect than the tide on the water level, but strong winds may also affect the water level. During exceptional conditions, such as storms and hurricanes, oceanic water may suddenly flow into the Baltic Sea at all depths. Such events give deep waters in the southern Baltic Sea higher salinity, which makes it possible for [[Atlantic cod|cod]] to breed there. If no such inflow of oceanic water to the Baltic Sea occurs for around a decade, the breeding of cod becomes endangered.

[[File:KronborgCastleDenmarkOct152022 07.jpg|thumb|right|275px|Kronborg castle is situated on the extreme northeastern tip of the island of Zealand at the narrowest point of the Øresund]]
[[File:oresund from helsingborg.jpg|thumb|275px|Northern Øresund]]

==History==
{{Main|Sound Dues}}

Political control of Øresund has been an important issue in Danish and [[Sweden|Swedish]] history. Denmark maintained [[military]] control with the [[coast]]al [[fortress]] of [[Kronborg]] at [[Elsinore]] on the west side and [[Kärnan]] at [[Helsingborg]] on the east, until the eastern shore was ceded to Sweden in 1658, based on the [[Treaty of Roskilde]]. Both fortresses are located where the strait is 4 kilometres wide.

In 1429, King [[Eric of Pomerania]] introduced the [[Sound Dues]] which remained in effect for more than four centuries, until 1857. Transitory dues on the use of waterways, roads, bridges and crossings were then an accepted way of taxing which could constitute a great part of a state's income. 
The Sound Dues remained the most important source of income for the Danish Crown for several centuries, thus making Danish kings relatively independent of Denmark's [[Privy Council of Denmark|privy council]] and [[aristocracy]].

To be independent of the Øresund tolls, Sweden carried out two great projects: the foundation of [[Gothenburg]] in 1621 and the construction of the [[Göta Canal]] from 1810 to 1832.

The [[Copenhagen Convention of 1857]] abolished the Dues and made the Danish straits an [[international waterway]].

A fixed connection was opened across the strait in 2000, the [[Øresund Bridge]].

==Notable islands==

===Denmark===
* [[Amager]] (western part is artificial enlargement from Øresund, or from Kalvebodene more precisely) 
* [[Saltholm]]
* [[Peberholm]] – an [[artificial island]]
* [[Middelgrundsfortet]] – an [[artificial island]]
* [[Flakfortet]] – an [[artificial island]]
* [[Amager Strandpark]] - an artificial beach area for Copenhagen
* [[Brøndby Strandpark]] - an artificial beach area for Copenhagen in [[Køge Bugt]]
* [[Vallensbæk-Ishøj Strandpark]] - an artificial beach area for Copenhagen in [[Køge Bugt]]

===Sweden===
* [[Ven, Sweden|Ven]] (Hven in older Swedish and Danish)
* [[Gråen]] – an artificial island outside port of Landskrona (enlargements from Øresund in the 17th and 20th centuries)

[[File:Øresund Panorama.jpg|thumb|450px|Øresund Strait from [[Malmö]]]]

==Notable sights==

===Denmark===
* [[Køge Bugt]] (Køge Bay)
* Nivå Bugt (Nivå Bay)
* Kalveboderne

===Sweden===
* [[Lundåkrabukten]] (Lundåkra Bay)
* [[Lommabukten]] (Lomma Bay)
* [[Höllviken (bight)|Höllviken]]
[[File:ORESUNDBRIDGE_WIDE.jpg|thumb|center|800px|Øresund Bridge, Øresund]]

==See also==

{{div col|colwidth=35em}}
* [[Great Belt]]
* [[Little Belt]]
* [[Kiel Canal]]
* [[Øresund Region]]
* [[Øresund Bridge]]
* [[Øresund Station|Øresund station]] on the [[Copenhagen Metro]]
* [[Øresundsmetro]] - a proposed bi-national metro system serving Copenhagen and Malmö
{{div col end}}

==References==
===Notes===
{{Reflist}}

===Bibliography===
* Menefee, Samuel Pyeatt, "The Strait Dues and Access to the Baltic Sea" in Renate Platzoder and Philomene Verlaan (eds.), ''The Baltic Sea: New Developments in National Policies and International Co-Operation '' (1996), pp.&nbsp;101–32.

==External links==
{{Commons category|Oresund}}
* [https://www.oresunddirekt.com/ Øresunddirekt] – Official public information site for the inhabitants of the Øresund region
* [http://www.tendensoresund.org/en Øresund Trends] {{Webarchive|url=https://web.archive.org/web/20120325233059/http://www.tendensoresund.org/en |date=2012-03-25 }} – An official public information site with up-to-date information on the region, available in English
* [http://www.oresundstid.dk/kap/start.aspx Øresundstid] – The History of the Øresund Region {{in lang|en|sv|da}}

{{Countries bordering the Baltic Sea}}
{{Borders of Denmark}}
{{Borders of Sweden}}
{{List of seas}}
{{Authority control}}

{{DEFAULTSORT:Oresund}}
[[Category:Straits of the Baltic Sea]]
[[Category:Straits of Denmark]]
[[Category:Straits of Sweden]]
[[Category:Geography of Copenhagen]]
[[Category:Landforms of Skåne County]]
[[Category:International straits]]
[[Category:Seas of Denmark]]
[[Category:Kronborg]]
[[Category:Øresund| ]]