{{short description|Group of islands in the Southern Ocean north-east of the Antarctic Peninsula}} {{about|islands in the Southern Ocean||Orkney (disambiguation)}} {{Infobox islands | name = South Orkney Islands | image_name = Signy Island Panorama.jpg | image_caption = Signy Island base and panorama | map_image = South Orkney Islands-en.svg | map_caption = Map of the South Orkney Islands | nickname = | archipelago = | total_islands = | major_islands = | coordinates = {{Coord|60|36|S|45|30|W|display=inline,title}} | area_km2 = 620 | length_mi = | width_mi = | highest_mount = | elevation_ft = 4153 | population = approx. 53-55 (summer) 14 (winter) | population_as_of = | density_km2 = | ethnic_groups = | country = Administered under the Antarctic Treaty System }}

The '''South Orkney Islands''' are a group of islands in the Southern Ocean, about {{cvt|604|km|mi}} north-east of the tip of the Antarctic Peninsula<ref name=McGonigal>[https://books.google.com/books?id=8bFcJgX0lIUC&pg=PA122 ''Antarctica: Secrets of the Southern Continent'' p. 122] {{webarchive |url=https://web.archive.org/web/20230325080030/https://books.google.com/books?id=8bFcJgX0lIUC&pg=PA122 |date=2023-03-25}}, David McGonigal, 2009</ref> and {{cvt|844|km|mi}} south-west of South Georgia Island. They have a total area of about {{cvt|620|km2|sqmi}}. The islands are claimed both by Britain (as part of the British Antarctic Territory since 1962, previously as a Falkland Islands Dependency) and by Argentina (as part of Argentine Antarctica). Under the 1959 Antarctic Treaty, sovereignty claims are held in abeyance. {{maplink |frame=yes |coord={{Coord|60|36|S|45|30|W}} |frame-width=360 |frame-height=360 |text=The South Orkney Islands are a group of islands in the Southern Ocean, about {{cvt|604|km|mi}} north-east of the tip of the Antarctic Peninsula.<ref name=McGonigal /> |zoom=2 |type=shape |stroke-colour=#C60C30 |stroke-width=3 |title=South Orkney Islands }}

Britain and Argentina both maintain bases on the islands. The Argentine base, Orcadas, established in 1904, is sited on Laurie Island. The 11 buildings of the Argentine station house up to 45 people during the summer, and an average of 14 during winter. The British Antarctic Survey base, Signy Research Station, is located on Signy Island and was established in 1947. Initially operated year-round, since 1995–1996 the Signy Research Station has been open only from November to April each year.

Apart from personnel at the bases, there are no permanent human inhabitants on the islands.

==History== [[File:Base Orcadas en 1929.png|thumb|left|250px|The Argentine Base Orcadas in 1929.]] [[File:Factory Cove - Signy Island.jpg|thumb|left|200px|The British Signy Research Station on Signy Island]] The South Orkney Islands were discovered in 1821 by two sealers, the American Nathaniel Brown Palmer and the Briton George Powell. The islands were originally named Powell's Group, with the main island named Coronation Island as it was the year of the coronation of King George IV. In 1823, James Weddell visited the islands, gave the archipelago its present name (after the Orkney Islands in the north of Scotland) and also renamed some of the islands. The South Orkney Islands are located at roughly the same latitude south as the Orkney Islands are north (60°S vs 59°N), although it is not known if this was a factor behind the naming of the islands. (Similarly, the South Shetland Islands, discovered in 1819 by William Smith, are roughly the same latitude south as the Shetland Islands are north: 62°S vs 60°N.)

Subsequently, the South Orkney Islands were frequently visited by sealers and whalers, but no thorough survey was done until the expedition of William Speirs Bruce on the ''Scotia'' in 1903, which overwintered at Laurie Island. Bruce surveyed the islands, reverted some of Weddell's name changes, and established a meteorological station, which was sold to the Argentine Government upon his departure in 1904. This base, renamed ''Orcadas'' in 1951, is still in operation {{As of|2007|alt=today}} and is thus the oldest research station continuously staffed in the Antarctic. [[File:1944 FID South Orkneys 6d stamp.jpg|right|thumb|A 1944 stamp of the Falkland Islands overprinted for use in the South Orkneys.]] In 1908, the United Kingdom declared sovereignty over various Antarctic and South American territories "to the south of the 50th parallel of south latitude, and lying between the 20th and the 80th degrees of west longitude", including the South Orkney Islands.<ref>[https://books.google.com/books?id=cIFAZPBKKuwC&pg=PA652 ''International law for Antarctica'' p. 652] {{Webarchive|url=https://web.archive.org/web/20230325080014/https://books.google.com/books?id=cIFAZPBKKuwC&pg=PA652 |date=2023-03-25 }}, Francesco Francioni and Tullio Scovazzi, 1996</ref> The Islands were subsequently administered as part of the Falkland Islands Dependencies. A biological research station on Signy Island was built in 1947 by the British Antarctic Survey, and was staffed year-round until 1996, when the Station staffing was reduced to 8–10 personnel who remained only during the southern hemisphere summer (November to April each year). In 1962, the islands became part of the newly established British Antarctic Territory.

The Argentine claim to the islands dates from 1925. It was originally justified by the Argentine occupation of the Laurie Island base and later subsumed into a wider territorial claim.<ref>[https://books.google.com/books?id=PYdBH4dOOM4C&pg=PA34 ''Exploring polar frontiers: a historical encyclopedia'', Volume 2, pp. 34–35] {{Webarchive|url=https://web.archive.org/web/20230325080106/https://books.google.com/books?id=PYdBH4dOOM4C&pg=PA34 |date=2023-03-25 }}, William James Mills, 2003</ref>

==Geography and climate== [[File:ORCADAS Tº 1901 2007.jpg|thumb|250px|left|Average air temperature readings of 1901 to 2007; NASA.]] The islands are situated at latitudes about 60°30' to 60°48'&nbsp;S and longitudes 44°25' to 46°43'&nbsp;W in the Southern Ocean. As a group of islands, the South Orkney Islands are at approximately {{Coord|60|36|S|45|30|W|scale:1000000}}.

The archipelago comprises four main islands. Coronation Island is the largest, measuring about {{cvt|30|mi|km}} long; its highest point is Mount Nivea which rises to {{cvt|4153|ft|m}} above sea level. Laurie Island is the easternmost of the islands. The other main islands are Powell and Signy. Smaller islands in the group include Robertson Islands, the Saddle Islands, and Acuña Island. The total area of the archipelago is about {{cvt|240|sqmi|km2}}, of which about 90 percent is glaciated.<ref name="McGonigal"/>

The Inaccessible Islands about {{cvt|15|nmi|mi km|lk=in}} to the west are considered part of the South Orkneys.

The climate of the South Orkneys is generally cold, wet, and windy. Summers are short and cold (December to March) when the average temperatures reach about {{cvt|3.5|°C|°F|lk=on}} and fall to about {{cvt|-12.8|°C|°F|0}} in July. The recorded temperature at Orcadas Base ranges between {{cvt|12|and|-44|°C|°F|1}}. The highest temperature recorded at Signy Research Station was {{convert|19.8|C}} on 30 January 1982, which is the highest temperature recorded anywhere south of 60°S.<ref>{{cite web |url=https://wmo.asu.edu/content/antarctica-highest-temperature |title=WMO Region VII (Antarctic: all land/ice south of 60°S): Highest Temperature |access-date=5 April 2022 }}</ref> The seas around the islands are ice-covered from late April to November.

South Orkney Trough ({{coord|60|0|S|45|0|W|}}) is an undersea trough named in association with the South Orkney Islands.

===Climate data=== Two stations are located on the islands. Data is sparse for Signy.

{{Weather box |location= Orcadas Base (Köppen ET) (1991−2020 normals, extremes 1903−present) |metric first= Yes |single line= Yes |collapsed = Yes | Jan record high C = 12.0 | Feb record high C = 12.3 | Mar record high C = 10.9 | Apr record high C = 12.6 | May record high C = 8.8 | Jun record high C = 9.8 | Jul record high C = 10.0 | Aug record high C = 9.0 | Sep record high C = 10.5 | Oct record high C = 9.6 | Nov record high C = 12.6 | Dec record high C = 11.6 |year record high C = 12.6 |Jan high C = 3.6 |Feb high C = 3.4 |Mar high C = 2.4 |Apr high C = 0.4 |May high C = -2.0 |Jun high C = -3.9 |Jul high C = -5.3 |Aug high C = -4.1 |Sep high C = -2.0 |Oct high C = 0.6 |Nov high C = 2.5 |Dec high C = 3.0 |year high C = -0.1 |Jan mean C = 1.3 |Feb mean C = 1.4 |Mar mean C = 0.3 |Apr mean C = -1.8 |May mean C = -5.0 |Jun mean C = -7.5 |Jul mean C = -9.4 |Aug mean C = -8.1 |Sep mean C = -5.6 |Oct mean C = -2.7 |Nov mean C = -0.6 |Dec mean C = 0.5 |year mean C = -3.1 |Jan low C = -0.7 |Feb low C = -0.4 |Mar low C = -1.6 |Apr low C = -4.1 |May low C = -8.1 |Jun low C = -11.3 |Jul low C = -14.1 |Aug low C = -12.4 |Sep low C = -9.8 |Oct low C = -6.0 |Nov low C = -3.2 |Dec low C = -1.7 |year low C = -6.1 | Jan record low C = -7.7 | Feb record low C = -7.9 | Mar record low C = -14.4 | Apr record low C = -24.0 | May record low C = -30.2 | Jun record low C = -39.8 | Jul record low C = -36.0 | Aug record low C = -44.0 | Sep record low C = -30.8 | Oct record low C = -27.6 | Nov record low C = -16.7 | Dec record low C = -8.7 |year record low C = -44.0 |precipitation colour = green | Jan precipitation mm = 43.9 | Feb precipitation mm = 73.5 | Mar precipitation mm = 73.0 | Apr precipitation mm = 73.4 | May precipitation mm = 62.6 | Jun precipitation mm = 52.1 | Jul precipitation mm = 44.8 | Aug precipitation mm = 51.6 | Sep precipitation mm = 48.0 | Oct precipitation mm = 48.2 | Nov precipitation mm = 44.7 | Dec precipitation mm = 46.4 |year precipitation mm = 662.2 |unit precipitation days = 0.1 mm |Jan precipitation days = 18 |Feb precipitation days = 20 |Mar precipitation days = 21 |Apr precipitation days = 20 |May precipitation days = 20 |Jun precipitation days = 18 |Jul precipitation days = 17 |Aug precipitation days = 18 |Sep precipitation days = 19 |Oct precipitation days = 20 |Nov precipitation days = 19 |Dec precipitation days = 18 |year precipitation days = 228 |Jan snow days = 15.6 |Feb snow days = 12.9 |Mar snow days = 16.8 |Apr snow days = 18.6 |May snow days = 19.2 |Jun snow days = 20.5 |Jul snow days = 18.9 |Aug snow days = 19.8 |Sep snow days = 19.5 |Oct snow days = 21.5 |Nov snow days = 19.0 |Dec snow days = 19.8 |year snow days = 221.9 |Jan humidity = 85 |Feb humidity = 86 |Mar humidity = 86 |Apr humidity = 86 |May humidity = 85 |Jun humidity = 85 |Jul humidity = 83 |Aug humidity = 84 |Sep humidity = 84 |Oct humidity = 86 |Nov humidity = 86 |Dec humidity = 86 |year humidity = 86 |Jan sun = 49.6 |Feb sun = 36.8 |Mar sun = 34.1 |Apr sun = 24.0 |May sun = 12.4 |Jun sun = 3.0 |Jul sun = 6.2 |Aug sun = 31.0 |Sep sun = 45.0 |Oct sun = 52.7 |Nov sun = 60.0 |Dec sun = 58.9 |year sun = |Jand sun = 1.6 |Febd sun = 1.3 |Mard sun = 1.1 |Aprd sun = 0.8 |Mayd sun = 0.4 |Jund sun = 0.1 |Juld sun = 0.2 |Augd sun = 1.0 |Sepd sun = 1.5 |Octd sun = 1.7 |Novd sun = 2.0 |Decd sun = 1.9 |yeard sun = 1.1 |Jan percentsun = 9.3 |Feb percentsun = 9.8 |Mar percentsun = 9.9 |Apr percentsun = 10.1 |May percentsun = 10.8 |Jun percentsun = 15.2 |Jul percentsun = 13.2 |Aug percentsun = 22.5 |Sep percentsun = 21.8 |Oct percentsun = 17.6 |Nov percentsun = 11.2 |Dec percentsun = 12.0 |year percentsun = 13.5 |source 1 = Servicio Meteorológico Nacional (temperature/snowy days/sun 1991–2020, precipitation days 1961–1990, humidity/percent sunshine 1903–1950)<ref name = SMNclimatenormals> {{cite web | url = https://ssl.smn.gob.ar/dpd/observaciones/estadisticas_normales_9120.zip | title = Estadísticas Climatológicas Normales - período 1991-2020 | publisher = Servicio Meteorológico Nacional | language = es | access-date = 16 May 2023}}</ref><ref name=SMNestadisticas>{{cite web | archive-url = https://web.archive.org/web/20230708235600/http://repositorio.smn.gob.ar/bitstream/handle/20.500.12160/2506/estad%C3%ADsticas_climatol%C3%B3gicas_normales_1991-2020.pdf?sequence=4&isAllowed=y | archive-date = 8 July 2023 | url = http://repositorio.smn.gob.ar/handle/20.500.12160/2506 | title = Estadísticas Climatológicas Normales – período 1991–2020 | publisher = Servicio Meteorológico Nacional | language = es | access-date = 8 July 2023 | year = 2023 | last1 = Nacional | first1 = Servicio Meteorológico }}</ref><ref name = SMN> {{cite web | url = http://www3.smn.gob.ar/serviciosclimaticos/?mod=elclima&id=5&var=antartida | title = Valores Medios de Temperatura y Precipitación-Antártida: Base Orcadas | publisher = Servicio Meteorológico Nacional | language = es | access-date = March 7, 2017}}</ref><ref name= NOAAsun>{{cite web | url = ftp://ftp.ngdc.noaa.gov/wdc/geomagnetism/docs/publications/1951/NationalMeteorologicalServiceofArgentina_1951_470.pdf | title = Datos climatológicos y geomagnéticos Islas Orcadas del Sur | publisher = Servicio Meteorológico Nacional | archive-url = https://web.archive.org/web/20210712181111/ftp://ftp.ngdc.noaa.gov/wdc/geomagnetism/docs/publications/1951/NationalMeteorologicalServiceofArgentina_1951_470.pdf | archive-date = 2021-07-12 | url-status = dead | access-date = March 21, 2015 }}</ref> |source 2 = NOAA (precipitation 1961–1990),<ref name= NOAA>{{Cite FTP | url = ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/ANTARCTICA/AA/88968.TXT | server = National Oceanic and Atmospheric Administration | title = BASE ORCADAS Climate Normals 1961-1990 | access-date = March 21, 2015}}</ref> Meteo Climat (record highs and lows)<ref name = meteoclimat> {{cite web | url = http://meteo-climat-bzh.dyndns.org/index.php?page=stati&id=37 | title = Station Iles Orcades du Sud | publisher = Météo Climat | language = fr | access-date = October 5, 2017}}</ref> |date= August 2010 }}

{{Weather box |location= Signy Research Station (Köppen ET) (1971–2000 normals) |metric first= yes |single line= yes |collapsed = yes |Jan record high C= 19.8 |Feb record high C= 16.2 |Mar record high C= 13.3 |Apr record high C= 4.6 |May record high C= 4.9 |Jun record high C= 3.9 |Jul record high C= 7.4 |Aug record high C= 3.3 |Sep record high C= 4.7 |Oct record high C= 6.6 |Nov record high C= 6.6 |Dec record high C= 3.6 |year record high C= |Jan high C= 6.1 |Feb high C= 6.4 |Mar high C= 6.3 |Apr high C= 0.7 |May high C= 0.2 |Jun high C= -2.0 |Jul high C= -4.6 |Aug high C= -5.0 |Sep high C= 0.9 |Oct high C= 1.1 |Nov high C= 2.0 |Dec high C= 1.6 |year high C= |Jan mean C= 1.2 |Feb mean C= 3.9 |Mar mean C= 3.1 |Apr mean C= -1.8 |May mean C= -2.1 |Jun mean C= -6.9 |Jul mean C= -7.4 |Aug mean C= -10.3 |Sep mean C= -2.9 |Oct mean C= -1.6 |Nov mean C= -0.8 |Dec mean C= -0.1 |year mean C= |Jan low C= -0.7 |Feb low C= 1.4 |Mar low C= -0.2 |Apr low C= -4.3 |May low C= -4.4 |Jun low C= -11.7 |Jul low C= -10.1 |Aug low C= -15.6 |Sep low C= -6.6 |Oct low C= -4.2 |Nov low C= -3.5 |Dec low C= -1.9 |year low C= |Jan record low C= -1.5 |Feb record low C= 1.0 |Mar record low C= -4.4 |Apr record low C= -8.8 |May record low C= -11.8 |Jun record low C= -27.8 |Jul record low C= -27.7 |Aug record low C= -25.4 |Sep record low C= -13.9 |Oct record low C= -8.7 |Nov record low C= -9.0 |Dec record low C= -3.8 |year record low C= |precipitation colour = |Jan precipitation mm= 33.7 |Feb precipitation mm= |Mar precipitation mm= 72.6 |Apr precipitation mm= 6.6 |May precipitation mm= 10.3 |Jun precipitation mm= 2.6 |Jul precipitation mm= 5.7 |Aug precipitation mm= 4.7 |Sep precipitation mm= 140.0 |Oct precipitation mm= |Nov precipitation mm= |Dec precipitation mm= 14.1 |year precipitation mm= |unit precipitation days= 1&nbsp;mm |Jan precipitation days= 11.63 |Feb precipitation days= |Mar precipitation days= 26.57 |Apr precipitation days= |May precipitation days= 5.17 |Jun precipitation days= |Jul precipitation days= |Aug precipitation days= 1.82 |Sep precipitation days= 10.00 |Oct precipitation days= |Nov precipitation days= |Dec precipitation days= 5.64 |year precipitation days= |source 1= Météo climat stats<ref>{{cite web |url=http://meteo-climat-bzh.dyndns.org/listenormale-1981-2010-1-p9.php|title=Moyennes 1981-2010 Antarctique|language=fr|access-date=11 November 2019}}</ref> |source 2= Météo Climat<ref>{{cite web|url=http://meteo-climat-bzh.dyndns.org/index.php?page=stati&id=2155|title=Météo Climat stats for Ile Signy |publisher=Météo Climat|access-date=11 November 2019}}</ref> }}

==Flora and fauna== Despite the harsh conditions, the islands do support vegetation and constitute the South Orkney Islands tundra ecoregion. All islands lie in the cold seas below the Antarctic Convergence. These areas support tundra vegetation consisting of mosses, lichens and algae, while seabirds, penguins and seals feed in the surrounding waters.

The littoral zone of the South Orkneys is either lifeless or very biologically poor. Amphipods and planarians exist under rocks, along with various algae, chitons, and some gastropods. With increasing water depth, life becomes more varied: starfish appear beyond 2–3 metres, along with sponges, urchins, and ascidians. At 8–10 metres, the variety of starfish increases along with the general biomass, and below 30 metres there are vast colonies of these creatures. Two penguin species, chinstrap (''Pygoscelis antarctica'') and Adélie (''Pygoscelis adeliae''), are present on land.<ref name="Schwartz2006">{{cite book|author=Maurice Schwartz|title=Encyclopedia of Coastal Science|url=https://books.google.com/books?id=VWnxpAxp6TMC&pg=PA87|year=2006|publisher=Springer Science & Business Media|isbn=978-1-4020-3880-8|page=87|access-date=2018-05-08|archive-date=2023-03-25|archive-url=https://web.archive.org/web/20230325080014/https://books.google.com/books?id=VWnxpAxp6TMC&pg=PA87|url-status=live}}</ref>

On Signy Island a parthenogenetic flightless midge originally from South Georgia, ''Eretmoptera murphyi'', was accidentally introduced during a botany experiment in the 1960s. It has since colonized much of the island and is altering the soil ecosystem. Some places can reach 20,000 individuals per m<sup>2</sup>. Because it can survive in water, there are concerns that it could reach other islands.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/pii/S0038071723000275 | doi=10.1016/j.soilbio.2023.108965 | title=Ecological consequences of a single introduced species to the Antarctic: Terrestrial impacts of the invasive midge Eretmoptera murphyi on Signy Island | journal=Soil Biology and Biochemistry | date=May 2023 | volume=180 | last1=Bartlett | first1=Jesamine C. | last2=Convey | first2=P. | last3=Newsham | first3=K. K. | last4=Hayward | first4=S. A. L. | bibcode=2023SBiBi.18008965B | hdl=11250/3092419 | hdl-access=free }}</ref><ref>[https://www.birmingham.ac.uk/news/2023/invading-insect-could-transform-antarctic-soils Invading insect could transform Antarctic soils]</ref>

==Research stations== thumb|right|Orcadas Base The two claimant nations maintain research stations on the islands. *{{ARG}} Orcadas Base, Laurie Island (since 1904 – bought as a meteorological station from British scientist William Speirs Bruce in 1904) *{{GBR}} Signy Research Station, Signy Island (since 1947)

==See also== {{cmn| *{{annotated link|Brisbane Heights}} *{{annotated link|Composite Gazetteer of Antarctica}} *Falkland Harbour *{{annotated link|Iceberg Bay}} *List of Antarctic and subantarctic islands *{{annotated link|Lynch Island}} *{{annotated link|Marshall Bay}} *{{annotated link|Moe Island}} *Monk Islands *{{annotated link|Norway Bight}} *{{annotated link|Orwell Bight}} *{{annotated link|Scientific Committee on Antarctic Research|abbreviation=SCAR}} *{{annotated link|Scotia Arc}} *{{annotated link|Scotia Sea}} *{{annotated link|Shagnasty Island}} *{{annotated link|Wave Peak}} *{{annotated link|Signy Island}} *{{annotated link|Spindrift Col}} }}

==References== {{reflist}}

==External links== {{Commons category|South Orkney Islands}} {{Wikivoyage}} *[http://gdl.cdlr.strath.ac.uk/scotia/vserm/vserm0503.htm Description of Bruce's expedition] *[http://www.galenfrysinger.com/south_orkney_islands.htm Images] *[https://web.archive.org/web/20051017074145/http://www.info.gov.ar/images/mapas/tierra.jpg Argentine Government Website with a map of the South Orkney Islands]

{{Geographic location | Centre = South Orkney Islands | N = ''Atlantic Ocean'' | NE = {{flagcountry|SGS}} <br /> ''Atlantic Ocean'' | E = ''Atlantic Ocean'' | SE = ''Southern Ocean'' | S = ''Southern Ocean'' <br /> Antarctica | SW = Antarctic Peninsula | W = ''Drake Passage'' <br /> South Shetland Islands | NW = {{flagcountry|FLK}} <br /> ''Drake Passage'' }} {{Portal bar|Geography|Islands}} {{Authority control}} Category:South Orkney Islands Category:Islands of Antarctica Category:Archipelagoes of the Southern Ocean Category:British Antarctic Territory Category:Argentine Antarctica Category:Disputed islands Category:Archipelagoes of Argentina Category:Seal hunting