Editing English Channel (section)

== Nature ==
=== Geography ===
[[File:English Channel.jpg|thumb|right|Map of the English Channel]]
{{anchor|Bay of the Seine}} <!-- term redirect to section -->

The [[International Hydrographic Organization]] defines the limits of the English Channel as:<ref name="IHO">{{Cite web |year=1971 |title=Limits of Oceans and Seas, 3rd edition + corrections |url=https://epic.awi.de/29772/1/IHO1953a.pdf |url-status=live |archive-url=https://web.archive.org/web/20160304000019/http://epic.awi.de/29772/1/IHO1953a.pdf |archive-date=4 March 2016 |access-date=9 May 2016 |publisher=International Hydrographic Organization |pages=42 [corrections to page 13] and 6}}</ref>

{{blockquote|{{indented plainlist|
* ''On the West.'' From the coast of [[Brittany]] westward along the parallel (48°28' N) of the East extreme of [[Ushant]] (Lédénès), through this island to West extreme thereof (Pointe de Pern), thence to the [[Bishop Rock]], the Southwest extreme of the [[Scilly Isles]], and on a line passing to the Westward of these Isles as far as the North extreme (Lion Rock) and thence Eastward to the [[Longships, Cornwall|Longships]] (50°04' N) and on to [[Land's End|Lands End]].
* ''On the East.'' The Southwestern limit of the [[North Sea]].
}}
}}

[[File:FranceGrisNez2Dover.jpg|thumb|The Strait of Dover viewed from France, looking towards England. The [[white cliffs of Dover]] on the English coast are visible from France on a clear day.]]
The [[Strait of Dover]] ({{langx|fr|Pas de Calais|link=no}}), at the Channel's eastern end, is its narrowest point, while its widest point lies between [[Lyme Bay]] and the Gulf of [[Saint Malo]], near its midpoint.<ref name="Columbia" /> Well on the continental shelf, it has an average depth of about {{convert|120|m|ft|abbr=on}} at its widest; yet averages about {{convert|45|m|ft|abbr=on}} between [[Dover]] and [[Calais]], its notable sandbank hazard being [[Goodwin Sands]]. Eastwards from there the adjoining North Sea reduces to about {{convert|26|m|ft|abbr=on}} across the [[Broad Fourteens]] (14 fathoms) where it lies over the southern cusp of the former land bridge between [[East Anglia]] and the [[Low Countries]]. The North Sea reaches much greater depths east of northern Britain.  The Channel descends briefly to {{convert|180|m|ft|abbr=on}} in the submerged valley of [[Hurd's Deep]], {{convert|48|km|mi|abbr=on}} west-northwest of [[Guernsey]].<ref>"English Channel" ''The Hutchinson Unabridged Encyclopedia including Atlas.'' 2005.</ref>

{{anchor|Bay of the Seine2}}[[File:Three French river mouths.JPG|thumb|Three French river mouths. Top to bottom: the [[River Somme|Somme]], the [[Authie (river)|Authie]] and the [[Canche]]]]
There are several major islands in the Channel, the most notable being the [[Isle of Wight]] off the English coast, and the [[Channel Islands]], British [[Crown Dependencies]] off the coast of France. The coastline, particularly on the French shore, is deeply indented, with several small islands close to the coastline, including [[Chausey]] and [[Mont-Saint-Michel]]. The [[Cotentin Peninsula]] on the French coast juts out into the Channel, with the wide Bay of the Seine ({{langx|fr|link=no|Baie de Seine}}) to its east. On the English side there is a small parallel [[strait]], the [[Solent]], between the Isle of Wight and the mainland. The [[Celtic Sea]] is to the west of the Channel.

The Channel acts as a funnel that amplifies the tidal range from less than a metre at sea in eastern places to more than 6 metres in the [[Channel Islands]], the west coast of the [[Cotentin Peninsula]] and the north coast of [[Brittany]] in monthly [[spring tide]]s. The time difference of about six hours between high water at the eastern and western limits of the Channel is indicative of the [[tidal range]] being amplified further by [[resonance]].<ref>{{Cite web |last=Thompson |first=LuAnne |author-link=LuAnne Thompson |title=Tide Dynamics – Dynamic Theory of Tides. |url=http://faculty.washington.edu/luanne/pages/ocean420/notes/tidedynamics.pdf |url-status=live |archive-url=https://web.archive.org/web/20160303221701/http://faculty.washington.edu/luanne/pages/ocean420/notes/tidedynamics.pdf |archive-date=3 March 2016 |access-date=14 April 2013 |publisher=University of Washington}}</ref>  Amphidromic points are the [[Bay of Biscay]] and varying more in precise location in the far south of the North Sea, meaning both those associated eastern coasts repel the tides effectively, leaving the Strait of Dover as every six hours the natural bottleneck short of its consequent gravity-induced repulsion of the southward tide (surge) of the North Sea (equally from the Atlantic).  The Channel does not experience, but its existence is necessary to explain the extent of [[North Sea storm surges]], such as necessitate the [[Thames Barrier]], [[Delta Works]], [[Zuiderzee works]] ([[Afsluitdijk]] and other dams).

In the UK [[Shipping Forecast]] the Channel is divided into the following areas, from the east:
* [[Dover]]
* [[Isle of Wight|Wight]]
* [[Isle of Portland|Portland]]
* [[Plymouth]]

=== Geological origins ===
[[File:Weichsel-Würm-Glaciation.png|thumb|Europe during the [[Last Glacial Maximum]] ca. 20,000 years ago]]
The full English Channel connecting the [[North Sea]] to the [[Western Atlantic]] via the [[Strait of Dover]] is of geologically recent origin, having formed late in the [[Pleistocene]] period.<ref>{{Cite encyclopedia |title=English Channel {{!}} channel, Europe |encyclopedia=Encyclopædia Britannica |url=https://www.britannica.com/place/English-Channel |access-date=16 May 2017 |language=en |archive-url=https://web.archive.org/web/20170403222035/https://www.britannica.com/place/English-Channel |archive-date=3 April 2017 |url-status=live}}</ref> The English Channel first developed as an arm of the Atlantic Ocean during the [[Pliocene]] period (5.3-2.6 million years ago) as a result of differential [[tectonic uplift]] along pre-existing tectonic weaknesses during the [[Oligocene]] and [[Miocene]] periods. During this early period, the Channel did not connect to the North Sea,<ref>{{Cite journal |last1=Lagarde |first1=J. L. |last2=Amorese |first2=D. |last3=Font |first3=M. |last4=Laville |first4=E. |last5=Dugué |first5=O. |date=March 2003 |title=The structural evolution of the English Channel area |url=https://onlinelibrary.wiley.com/doi/10.1002/jqs.744 |journal=Journal of Quaternary Science |language=en |volume=18 |issue=3–4 |pages=201–213 |doi=10.1002/jqs.744 |bibcode=2003JQS....18..201L |issn=0267-8179|url-access=subscription }}</ref> with [[Great Britain|Britain]] and [[Ireland]] remaining part of [[continental Europe]], linked by an unbroken [[Weald-Artois Anticline|Weald–Artois anticline]], a ridge running between the Dover and Calais regions. During Pleistocene glacial periods this ridge acted as a natural dam holding back a large freshwater [[pro-glacial lake]] in the [[Doggerland]] region, now submerged under the [[North Sea]]. During this period, the North Sea and almost all of the British Isles were covered by ice. The lake was fed by meltwater from the Baltic and from the Caledonian and Scandinavian [[ice sheet]]s that joined to the north, blocking its exit. The sea level was about {{convert|120|m|ft|abbr=on}} lower than it is today. Then, between 450,000 and 180,000&nbsp;years ago, at least two catastrophic [[glacial lake outburst flood]]s breached the Weald–Artois anticline. These contributed to creating some of the deepest parts of the channel such as [[Hurd's Deep]].

The first flood of 450,000 years ago  would have lasted for several months, releasing as much as one million cubic metres of water per second.<ref name="Gupta Nature">{{Cite journal |last1=Gupta |first1=Sanjeev |last2=Jenny S. Collier, Andy Palmer-Felgate & Graeme Potter |last3=Palmer-Felgate |first3=Andy |last4=Potter |first4=Graeme |year=2007 |title=Catastrophic flooding origin of shelf valley systems in the English Channel |journal=[[Nature (journal)|Nature]] |volume=448 |issue=7151 |pages=342–345 |bibcode=2007Natur.448..342G |doi=10.1038/nature06018 |pmid=17637667 |s2cid=4408290}}
*{{cite news |author=Dave Mosher |date=18 July 2007 |title=Why the rift between Britain and France? |work=[[NBC News]] |url=https://www.nbcnews.com/id/wbna19833064}}</ref><ref name="PhysToday">{{Cite journal |last=Schwarzschild |first=Bertram |date=September 2007 |title=Sonar mapping suggests that the English Channel was created by two megafloods |url=http://www.qpg.geog.cam.ac.uk/research/projects/englishchannelfloods/physicstoday.pdf |url-status=live |journal=Physics Today |volume=60 |issue=9 |pages=24–27 |bibcode=2007PhT....60i..24S |doi=10.1063/1.2784673 |archive-url=https://web.archive.org/web/20111002162907/http://www.qpg.geog.cam.ac.uk/research/projects/englishchannelfloods/physicstoday.pdf |archive-date=2 October 2011 |access-date=27 April 2010}}</ref> The flood started with large but localised waterfalls over the ridge, which excavated depressions now known as the ''Fosses [[Louis Dangeard|Dangeard]]''. The flow eroded the retaining ridge, causing the rock dam to fail and releasing lake water into the Atlantic. After multiple episodes of changing sea level, during which the ''Fosses Dangeard'' were largely infilled by various layers of sediment, another catastrophic flood some 180,000 years ago carved a large bedrock-floored valley, the [[Lobourg Channel]], some 500 m wide and 25 m deep, from the southern North Sea basin through the centre of the [[Straits of Dover]] and into the English Channel.<ref name="PhysToday" /> It left streamlined islands, longitudinal erosional grooves, and other features characteristic of catastrophic [[megaflood]] events, still present on the sea floor and now revealed by high-resolution sonar.<ref>{{Cite journal |last1=Gupta |first1=Sanjeev |last2=Collier |first2=Jenny S. |last3=Garcia-Moreno |first3=David |last4=Oggioni |first4=Francesca |last5=Trentesaux |first5=Alain |last6=Vanneste |first6=Kris |last7=De Batist |first7=Marc |last8=Camelbeeck |first8=Thierry |last9=Potter |first9=Graeme |last10=Van Vliet-Lanoë |first10=Brigitte |last11=Arthur |first11=John C. R. |year=2017 |title=Two-stage opening of the Dover Strait and the origin of island Britain |journal=Nature Communications |volume=8 |pages=15101 |bibcode=2017NatCo...815101G |doi=10.1038/ncomms15101 |pmc=5382280 |pmid=28375202}}</ref><ref>{{Cite journal |last1=Gupta |first1=Sanjeev |last2=Collier |first2=Jenny S. |last3=Palmer-Felgate |first3=Andy |last4=Potter |first4=Graeme |year=2007 |title=Catastrophic flooding origin of shelf valley systems in the English Channel |journal=Nature |volume=448 |issue=7151 |pages=342–345 |bibcode=2007Natur.448..342G |doi=10.1038/nature06018 |pmid=17637667 |s2cid=4408290}}</ref><ref>{{Cite web |date=19 July 2007 |title=Catastrophic Flooding Changed the Course of British History |url=https://www.sciencedaily.com/releases/2007/07/070718140833.htm |url-status=live |archive-url=https://web.archive.org/web/20170703151736/https://www.sciencedaily.com/releases/2007/07/070718140833.htm |archive-date=3 July 2017 |access-date=28 February 2018 |website=Science Daily}}</ref> Through the scoured channel passed a river, the [[Channel River]], which drained the combined [[Rhine]] and [[Thames]] westwards to the Atlantic.

The flooding destroyed the ridge that connected Britain to [[continental Europe]], although a land connection across the southern [[North Sea]] would have existed intermittently at later times when periods of [[glaciation]] resulted in lowering of sea levels.<ref>{{Cite web |last=Bryony Coles |title=The Doggerland project |url=http://humanities.exeter.ac.uk/archaeology/research/projects/title,89282,en.html |url-status=dead |archive-url=https://web.archive.org/web/20200606132746/http://humanities.exeter.ac.uk/archaeology/research/projects/title_89282_en.html |archive-date=6 June 2020 |access-date=3 January 2011 |publisher=University of Exeter}}</ref>

During [[interglacial]] periods (when sea levels were high) between the initial flooding 450,000 years ago until around 180,000 years ago, the Channel would still have been separated from the North Sea by a land bridge to the north of the Strait of Dover (the Strait of Dover at this time formed part of a [[estuary]] fed by the Thames and [[Scheldt]]), restricting interchange of marine fauna between the Channel and the North Sea (except perhaps by occasional overtopping). During the [[Last Interglacial|Last Interglacial/Eemian]] (115–130,000 years ago) the connection between the North Sea and the English Channel was fully open as it is today, resulting in Britain being an island during this interval, before lowered sea levels reconnected it to the continent during the [[Last Glacial Period]].<ref>{{Cite journal |last1=Hijma |first1=Marc P. |last2=Cohen |first2=Kim M. |last3=Roebroeks |first3=Wil |last4=Westerhoff |first4=Wim E. |last5=Busschers |first5=Freek S. |date=January 2012 |title=Pleistocene Rhine–Thames landscapes: geological background for hominin occupation of the southern North Sea region |url=https://onlinelibrary.wiley.com/doi/10.1002/jqs.1549 |journal=Journal of Quaternary Science |language=en |volume=27 |issue=1 |pages=17–39 |doi=10.1002/jqs.1549 |bibcode=2012JQS....27...17H |issn=0267-8179|url-access=subscription }}</ref> From the end of the Last Glacial Period, to the beginning of the Holocene rising sea levels again resulted in the unimpeded connection between the North Sea and the English Channel resuming due to the sinking of [[Doggerland]], with Britain again becoming an island.<ref>{{Cite journal |last1=Bicket |first1=Andrew |last2=Tizzard |first2=Louise |date=December 2015 |title=A review of the submerged prehistory and palaeolandscapes of the British Isles |url=https://linkinghub.elsevier.com/retrieve/pii/S0016787815000978 |journal=Proceedings of the Geologists' Association |language=en |volume=126 |issue=6 |pages=643–663 |doi=10.1016/j.pgeola.2015.08.009|bibcode=2015PrGA..126..643B |url-access=subscription }}</ref>

=== Ecology ===
As a busy shipping lane, the Channel experiences environmental problems following accidents involving ships with toxic cargo and oil spills.<ref>{{Cite news |date=1 February 2006 |title=Tanker wreck starts leaking oil |publisher=BBC |location=London |url=http://news.bbc.co.uk/1/hi/world/europe/guernsey/4668664.stm |url-status=live |access-date=1 November 2008 |archive-url=https://web.archive.org/web/20070103192242/http://news.bbc.co.uk/1/hi/world/europe/guernsey/4668664.stm |archive-date=3 January 2007}}</ref> Indeed, over 40% of the UK incidents threatening pollution occur in or very near the Channel.<ref>{{Cite web |year=2006 |title=Annual Survey of Reported Discharges |url=http://www.mcga.gov.uk/c4mca/pacops_final_report_2006.pdf |url-status=live |archive-url=https://web.archive.org/web/20091112181910/http://www.mcga.gov.uk/c4mca/pacops_final_report_2006.pdf |archive-date=12 November 2009 |access-date=1 November 2008 |publisher=[[Maritime and Coastguard Agency]]}}</ref> One occurrence was the [[MSC Napoli|MSC ''Napoli'']], which on 18 January 2007 was beached with nearly 1700&nbsp;tonnes of dangerous cargo in Lyme Bay, a protected World Heritage Site coastline.<ref>{{Cite web |title=MSC Napoli {{!}} Ship Disasters |url=http://www.ship-disasters.com/commercial-ship-disasters/container-ship-disasters/msc-napoli/ |url-status=dead |archive-url=https://web.archive.org/web/20190312233239/http://www.ship-disasters.com/commercial-ship-disasters/container-ship-disasters/msc-napoli/ |archive-date=12 March 2019 |access-date=3 February 2017 |website=www.ship-disasters.com |language=en-US}}</ref> The ship had been damaged and was en route to [[Portland Harbour]].

The English Channel, despite being a busy shipping lane, remains in part a haven for wildlife. Atlantic oceanic species are more common in the westernmost parts of the channel, particularly to the west of [[Start Point, Devon]], but can sometimes be found further east towards Dorset and the Isle of Wight. Seal sightings are becoming more common along the English Channel, with both [[grey seal]] and [[harbour seal]] recorded frequently.