Bothnian Bay#Climate
{{Short description|Bay in the northern Bothnian Sea}}
{{Use dmy dates|date=September 2023}}
{{Infobox body of water
| name = Bothnian Bay
| other_name = Bay of Bothnia
| image =Ohtakari.JPG
| alt = See caption
| caption = The rocky shoreline of Ohtakari, in the southeast of the bay
| image_bathymetry =
| caption_bathymetry =
| pushpin_map = Europe
| pushpin_map_caption = Location of the Bothnian Bay in Europe
| pushpin_map_alt = Map
| location = Fennoscandia
| coords = {{Coord|65|N|023|E|type:waterbody_scale:2000000|display=inline,title}}
| type = Sea
| inflow =
| outflow = Bothnian Sea
| catchment = {{convert|260675|km2|abbr=on}}
| basin_countries = Finland, Norway, and Sweden
| length =
| width =
| area = {{convert|36800|km2|abbr=on}}
| depth = {{convert|43|m|abbr=on}}
| max-depth = {{convert|147|m|abbr=on}}
| volume = {{convert|1490|km3|abbr=on}}
| residence_time =
| shore =
| elevation =
| frozen = 110–190 days annually
| islands =
| cities =
| reference =
}}
The Bothnian Bay or Bay of Bothnia ({{Langx|sv|Bottenviken}}; {{Langx|fi|Perämeri}}) is the northernmost part of the Gulf of Bothnia, which is in turn the northern part of the Baltic Sea. The land holding the bay is still rising after the weight of ice-age glaciers has been removed, and within 2,000 years the bay will be a large freshwater lake since its link to the south Kvarken is mostly less than {{convert|20|m|ft}} deep. The bay today is fed by several large rivers, and is relatively unaffected by tides, so has low salinity. It freezes over each year for up to six months. Compared to other parts of the Baltic, it has little plant or animal life.
Extent
The bay is divided from the Bothnian Sea, the southern part of the Gulf of Bothnia, by the Northern Quark (Kvarken) strait.
The Northern Quark has a greatest depth of {{convert|65|m}}, with two ridges that are just {{convert|25|m}} deep. It lies between a group of islands off Vaasa in Finland and another group at Holmöarna in Sweden.{{sfn|Leppäranta|Myrberg|2009|p=55}}
The bay is bounded by Finland to the east and Sweden to the west.
The bay is asymmetric, with a smoother and shallower bottom slope on the Finnish side, and a deeper bottom with a steeper and more rugged coast on the Swedish side.{{sfn|Leppäranta|Myrberg|2009|p=55}}
The Bothnian Bay has a catchment area of {{convert|260675|km2}}.
Of this, 56% lies in Finland, 44% in Sweden and less than 1% in Norway.{{sfn|Szefer|2002|p=11}}
The catchment contains about {{convert|11500000|ha}} of forest, split roughly equally between Sweden and Finland.{{sfn|Baltic Sea Joint Comprehensive Environmental Action|pp=2–3}}
The average depth is {{convert|41|m}}.
The Luleå Deep is the deepest part of the bay, at {{convert|146|m}}, southeast of the town of Luleå.{{sfn|Leppäranta|Myrberg|2009|p=56}}
On the Finnish side the average depth is {{convert|30|m}}. The deepest part is near the island of Lönkytin, with a depth of {{convert|50|m}}.{{sfn|Merikartta Perämeri osa 57}}
File:Bottenviken.png|Map of the Gulf of Bothnia showing location of Bothnian Bay (shaded and labelled Bottenviken)
File:Bothnian Bay map-fi.png|Finnish map of the bay – click to enlarge
File:Scandinavia M2002074 lrg.jpg|Satellite image of Fennoscandia with sea ice covering the Bothnian Bay (white region in center)
=Isostatic rebound=
The bay lies in the area in Northern Europe where the ice was at its thickest during the last ice age.{{sfn|Røed|2011}} The Bay of Bothnia was under ice until the "Ancylus Lake" period (7500–6000 BC), when the ice sheet withdrew to the mountains of Northern Scandinavia.{{sfn|Leppäranta|Myrberg|2009|p=11}}
The land is now rising by post-glacial rebound at the highest rate in the Baltic Sea, at an estimated rate of {{convert|9|mm}} a year.{{sfn|Nesje|2006}}
Today the Bothnian Bay lies around {{convert|300|m}} higher than it did at the end of the Last Ice Age.{{sfn|Røed|2011}}
The local population has seen the sea retreating during their lifetimes from piers and boathouses, leaving them stranded on land.
Some former islands such as Porsön and Hertsön near the city of Luleå are still called islands, but are now connected to the mainland.{{sfn|About the Bay ... Bottenvikens skärgård}}
The maximum depth at the Kvarken sound today is around {{convert|20|m}}. Within 2,000 years, the exit from the bay at Kvarken will be raised above sea level, which will result in it becoming Europe's largest lake.{{cite journal |last1=Tikkanen |first1=Matti |last2=Oksanen |first2=Juha |date=2002 |title=Late Weichselian and Holocene shore displacement history of the Baltic Sea in Finland |url=http://www.helsinki.fi/maantiede/geofi/fennia/demo/pages/oksanen.htm |journal=Fennia |volume=180 |issue=1–2 |access-date=December 22, 2017 }}
Hydrology
File:Vihreasaari Oulu 2006 11 04.JPG, Finland, while the Bay of Bothnia starts to freeze for the winter]]
File:Hailuoto Ice Road 20130113 05 (lightened and filtered).jpg island and the mainland]]
The Bothnian Bay has a harsher environment than other parts of the greater Baltic Sea.{{sfn|Eleftheriou|Smith|Ansell|1995|p=23}}
The bay is ice-covered for 110 to 190 days each year.{{sfn|Müller|1982|p=8}}
Tides have little effect, but high winds driving the water from the south or north may cause the water level to rise or fall by {{convert|1.5|m}}.{{sfn|About the Bay ... Bottenvikens skärgård}}
Major rivers that flow into the bay include:
| class="wikitable sortable" | ||
| River | Country | Discharge |
|---|---|---|
| Kemijoki | Finland | {{convert|556|m3/s|abbr=on}} |
| Lule River | Sweden | {{convert|506|m3/s|abbr=on}} |
| Torne River | Sweden and Finland | {{convert|388|m3/s|abbr=on}} |
| Kalix River | Sweden | {{convert|295|m3/s|abbr=on}} |
| Oulujoki | Finland | {{convert|250|m3/s|abbr=on}} |
| Pite River | Sweden | {{convert|167|m3/s|abbr=on}} |
| Skellefte River | Sweden | {{convert|162|m3/s|abbr=on}} |
| Iijoki | Finland | {{convert|164|m3/s|abbr=on}} |
The salinity is only about 0.2 psu in the northern part of the bay, dropping almost to zero in some of the archipelagos with large river inflows.{{sfn|Eleftheriou|Smith|Ansell|1995|p=24}} The low salinity and cold temperatures in winter results in ice that is considerably stronger than more saline or warmer ice.{{sfn|Mäkinen|1972|p=3}}
Islands
{{main|List of islands of Bothnian Bay}}
File:Hermanni Islands in Oulu 2006 11 04.JPG
The lighthouse on the island of [[Pite-Rönnskär in Bothnian Bay|thumb]]
If an island is defined as an area of land more than {{convert|20|m2}} that is surrounded by water, the Bay of Bothnia has 4,001 islands.{{sfn|About the Bay ... Bottenvikens skärgård}} The largest island is Hailuoto.{{sfn|Leppäranta|Myrberg|2009|p=55}} The north of the bay contains a large archipelago area.{{sfn|Leppäranta|Myrberg|2009|p=55}}
The Swedish portion of this area is the Norrbotten archipelago.{{sfn|Ankre|2005|p=8}} This is divided into the Piteå, Luleå, Kalix and Haparanda archipelagos.{{sfn|Index: bottenviken.se}} Many of the islands are uninhabited and in a natural state.{{sfn|Sweden: Rough Guides 2003|p=403}} In the winter the larger islands may be accessed via ice roads. Some of them are inhabited or have seasonal fishing villages used by people from the mainland.{{sfn|About the Bay ... Bottenvikens skärgård}}
The Swedish Haparanda Archipelago National Park ({{langx|sv|Haparanda skärgårds nationalpark}}) occupies the Haparanda group of islands, bordering the Finnish Bothnian Bay National Park. It includes the larger islands of Sandskär and Seskar Furö, and some smaller islands and skerries. All of these islands have emerged in the last 1,500 years as the bed of the bay has risen.{{sfn|Haparanda Skärgård National Park}} The Bay of Bothnia National Park in the Finnish section ({{langx|fi|Perämeren kansallispuisto}}, {{langx|sv|Bottenvikens nationalpark}}), established in 1991, is located in the archipelago offshore from Tornio and Kemi. It covers {{convert|157|km2}} of which about {{convert|2.5|km2}} is land.{{sfn|Bay of Bothnia National Park}}
Climate
The immediate coastal areas of the Bothnian Bay tend to be bordering between humid continental and subarctic climates. The summers on the coastlines are the northernmost coastlines to average above {{convert|20|C|F}} in summer. In winter the sea freezes over, many times completely. This means that there is vast seasonal lag offshore such as on the island of Rödkallen on the Swedish side. Due to the mild nature of summers and the low diurnals, offshore islands tend to be humid continental since September usually stays above {{convert|10|C|F}} means.
{{Weather box
|location = Luleå Airport, 2002–2020 averages; extremes since 1944
|collapsed =
|metric first = Yes
|single line = Yes
|Jan record high C = 10.3
|Feb record high C = 9.8
|Mar record high C = 13.4
|Apr record high C = 18.1
|May record high C = 28.4
|Jun record high C = 32.2
|Jul record high C = 32.1
|Aug record high C = 29.2
|Sep record high C = 22.5
|Oct record high C = 16.9
|Nov record high C = 13.0
|Dec record high C = 8.5
|year record high C = 32.2
|Jan avg record high C = 4.0
|Feb avg record high C = 5.3
|Mar avg record high C = 8.7
|Apr avg record high C = 13.3
|May avg record high C = 21.4
|Jun avg record high C = 24.3
|Jul avg record high C = 26.7
|Aug avg record high C = 24.1
|Sep avg record high C = 18.8
|Oct avg record high C = 12.5
|Nov avg record high C = 7.2
|Dec avg record high C = 5.3
|year avg record high C = 27.8
|Jan high C = -5.2
|Feb high C = -4.5
|Mar high C = 0.2
|Apr high C = 5.6
|May high C = 12.3
|Jun high C = 17.4
|Jul high C = 20.5
|Aug high C = 18.7
|Sep high C = 13.4
|Oct high C = 5.9
|Nov high C = 0.6
|Dec high C = -2.0
|year high C =
|Jan mean C = -9.1
|Feb mean C = -8.7
|Mar mean C = -4.2
|Apr mean C = 1.5
|May mean C = 7.7
|Jun mean C = 13.3
|Jul mean C = 16.6
|Aug mean C = 15.0
|Sep mean C = 9.9
|Oct mean C = 2.9
|Nov mean C = -2.4
|Dec mean C = -5.6
|year mean C =
|Jan low C = -13.0
|Feb low C = -12.9
|Mar low C = -8.5
|Apr low C = -2.6
|May low C = 3.1
|Jun low C = 9.1
|Jul low C = 12.6
|Aug low C = 11.2
|Sep low C = 6.3
|Oct low C = -0.2
|Nov low C = -5.4
|Dec low C = -9.1
|year low C =
|Jan avg record low C = -26.6
|Feb avg record low C = -25.7
|Mar avg record low C = -20.1
|Apr avg record low C = -10.2
|May avg record low C = -3.1
|Jun avg record low C = 3.5
|Jul avg record low C = 7.3
|Aug avg record low C = 4.3
|Sep avg record low C = -0.9
|Oct avg record low C = -9.7
|Nov avg record low C = -15.8
|Dec avg record low C = -21.2
|year avg record low C = -29.2
|Jan record low C = -42.3
|Feb record low C = -38.2
|Mar record low C = -32.3
|Apr record low C = -20.4
|May record low C = -8.8
|Jun record low C = -1.2
|Jul record low C = 3.2
|Aug record low C = -0.2
|Sep record low C = -8.4
|Oct record low C = -20.7
|Nov record low C = -30.3
|Dec record low C = -33.7
|year record low C = -42.3
|precipitation colour = green
|Jan precipitation mm = 57.9
|Feb precipitation mm = 36.8
|Mar precipitation mm = 30.2
|Apr precipitation mm = 31.3
|May precipitation mm = 45.1
|Jun precipitation mm = 65.8
|Jul precipitation mm = 67.6
|Aug precipitation mm = 69.5
|Sep precipitation mm = 66.0
|Oct precipitation mm = 52.9
|Nov precipitation mm = 52.6
|Dec precipitation mm = 56.3
|year precipitation mm =
|snow colour = green
|Jan snow depth cm = 55
|Feb snow depth cm = 72
|Mar snow depth cm = 75
|Apr snow depth cm = 64
|May snow depth cm = -
|Jun snow depth cm = 0
|Jul snow depth cm = 0
|Aug snow depth cm = 0
|Sep snow depth cm = 0
|Oct snow depth cm = 5
|Nov snow depth cm = 16
|Dec snow depth cm = 30
|year snow depth cm = 79
|Jan sun = 21
|Feb sun = 78
|Mar sun = 172
|Apr sun = 225
|May sun = 289
|Jun sun = 305
|Jul sun = 310
|Aug sun = 245
|Sep sun = 154
|Oct sun = 92
|Nov sun = 38
|Dec sun = 3
|year sun =
|source 1 = SMHI{{cite web
|url = http://www.smhi.se/klimatdata/meteorologi/temperatur/2.1240
|title = Statistik från väder och vatten – Månads och årsstatistik
|language = sv
|access-date = 31 May 2021
|publisher = Swedish Meteorological and Hydrological Institute
|archive-date = 2 May 2019
|archive-url = https://web.archive.org/web/20190502092934/http://www.smhi.se/klimatdata/meteorologi/temperatur/2.1240
|url-status = dead
}}
|source 2 = SMHI{{cite web
|url = https://www.smhi.se/klimatdata/meteorologi/ladda-ner-meteorologiska-observationer/#param=precipitationMonthlySum,stations=all,stationid=162860
|title = SMHI Open Data for Luleå
|language = sv
|access-date = 31 May 2021
|publisher = Swedish Meteorological and Hydrological Institute
|archive-date = 11 April 2019
|archive-url = https://web.archive.org/web/20190411092753/https://www.smhi.se/klimatdata/meteorologi/ladda-ner-meteorologiska-observationer#param=precipitationMonthlySum,stations=all,stationid=162860
|url-status = dead
}}
}}
{{Weather box
|location = Rödkallen, (2002–2020 averages; extremes from available data since 1961; sunshine from Luleå 2002–2020)
|collapsed =
|metric first = Yes
|single line = Yes
|Jan record high C = 7.1
|Feb record high C = 7.0
|Mar record high C = 6.9
|Apr record high C = 10.2
|May record high C = 21.9
|Jun record high C = 26.2
|Jul record high C = 28.9
|Aug record high C = 25.0
|Sep record high C = 19.2
|Oct record high C = 13.3
|Nov record high C = 10.0
|Dec record high C = 5.6
|year record high C =
|Jan avg record high C = 2.5
|Feb avg record high C = 2.6
|Mar avg record high C = 4.2
|Apr avg record high C = 7.3
|May avg record high C = 15.7
|Jun avg record high C = 20.1
|Jul avg record high C = 22.4
|Aug avg record high C = 21.1
|Sep avg record high C = 16.5
|Oct avg record high C = 11.1
|Nov avg record high C = 6.4
|Dec avg record high C = 3.8
|year avg record high C = 23.4
|Jan high C = -3.4
|Feb high C = -4.1
|Mar high C = -1.4
|Apr high C = 2.6
|May high C = 8.3
|Jun high C = 14.2
|Jul high C = 18.1
|Aug high C = 17.2
|Sep high C = 12.8
|Oct high C = 6.7
|Nov high C = 2.5
|Dec high C = -0.6
|year high C =
|Jan mean C = -6.1
|Feb mean C = -7.4
|Mar mean C = -4.7
|Apr mean C = 0.2
|May mean C = 5.9
|Jun mean C = 12.0
|Jul mean C = 16.2
|Aug mean C = 15.5
|Sep mean C = 11.1
|Oct mean C = 5.1
|Nov mean C = 0.8
|Dec mean C = -2.7
|year mean C =
|Jan low C = -8.7
|Feb low C = -10.6
|Mar low C = -8.0
|Apr low C = -2.3
|May low C = 3.4
|Jun low C = 9.8
|Jul low C = 14.2
|Aug low C = 13.7
|Sep low C = 9.4
|Oct low C = 3.5
|Nov low C = -1.0
|Dec low C = -4.8
|year low C =
|Jan avg record low C = -20.9
|Feb avg record low C = -22.3
|Mar avg record low C = -17.7
|Apr avg record low C = -8.6
|May avg record low C = -1.3
|Jun avg record low C = 5.6
|Jul avg record low C = 10.4
|Aug avg record low C = 9.2
|Sep avg record low C = 4.1
|Oct avg record low C = -2.6
|Nov avg record low C = -7.4
|Dec avg record low C = -13.8
|year avg record low C = -25.3
|Jan record low C = -38.0
|Feb record low C = -33.1
|Mar record low C = -27.0
|Apr record low C = -19.7
|May record low C = -9.0
|Jun record low C = 1.7
|Jul record low C = 6.5
|Aug record low C = 5.6
|Sep record low C = -0.4
|Oct record low C = -10.3
|Nov record low C = -20.5
|Dec record low C = -27.7
|year record low C =
|precipitation colour = green
|Jan precipitation mm = 25.5
|Feb precipitation mm = 19.3
|Mar precipitation mm = 18.6
|Apr precipitation mm = 21.7
|May precipitation mm = 32.8
|Jun precipitation mm = 47.0
|Jul precipitation mm = 49.2
|Aug precipitation mm = 46.8
|Sep precipitation mm = 47.6
|Oct precipitation mm = 50.0
|Nov precipitation mm = 44.8
|Dec precipitation mm = 40.0
|year precipitation mm =
|Jan sun = 21
|Feb sun = 78
|Mar sun = 172
|Apr sun = 225
|May sun = 289
|Jun sun = 305
|Jul sun = 310
|Aug sun = 245
|Sep sun = 154
|Oct sun = 92
|Nov sun = 38
|Dec sun = 3
|year sun =
|source 1 = SMHI Open Data{{cite web
| url = https://www.smhi.se/data/meteorologi/ladda-ner-meteorologiska-observationer#param=airTemperatureMinAndMaxOnceEveryDay,stations=all,stationid=162790
|title= SMHI Open Data
| publisher = Swedish Meteorological and Hydrological Institute | language = sv}}
|source 2 = SMHI Open Data{{cite web
| url = https://www.smhi.se/data/meteorologi/ladda-ner-meteorologiska-observationer#param=precipitationMonthlySum,stations=all,stationid=162790
|title = SMHI Open Data
| publisher = SMHI| language=sv |date = 17 April 2021}}
|date=April 2021}}
{{Weather box
|collapsed = yes
|metric first = yes
|single line = yes
|location = Haparanda (2002–2020; extremes since 1901)
|Jan record high C = 8.4
|Feb record high C = 7.8
|Mar record high C = 10.3
|Apr record high C = 18.5
|May record high C = 28.8
|Jun record high C = 31.4
|Jul record high C = 33.6
|Aug record high C = 29.7
|Sep record high C = 24.0
|Oct record high C = 17.0
|Nov record high C = 11.5
|Dec record high C = 7.0
|year record high C =
|Jan avg record high C = 2.5
|Feb avg record high C = 3.4
|Mar avg record high C = 7.5
|Apr avg record high C = 12.7
|May avg record high C = 22.3
|Jun avg record high C = 25.2
|Jul avg record high C = 27.1
|Aug avg record high C = 24.6
|Sep avg record high C = 18.7
|Oct avg record high C = 11.8
|Nov avg record high C = 6.4
|Dec avg record high C = 3.7
|year avg record high C = 28.1
|Jan high C = -5.9
|Feb high C = -5.1
|Mar high C = -0.3
|Apr high C = 5.4
|May high C = 12.3
|Jun high C = 17.8
|Jul high C = 21.1
|Aug high C = 18.7
|Sep high C = 13.3
|Oct high C = 5.6
|Nov high C = 0.4
|Dec high C = -2.4
|year high C =
|Jan mean C = -9.8
|Feb mean C = -9.1
|Mar mean C = -4.9
|Apr mean C = 1.1
|May mean C = 7.4
|Jun mean C = 12.9
|Jul mean C = 16.5
|Aug mean C = 14.4
|Sep mean C = 9.4
|Oct mean C = 2.4
|Nov mean C = -2.4
|Dec mean C = -5.8
|year mean C =
|Jan low C = -13.6
|Feb low C = -13.1
|Mar low C = -9.5
|Apr low C = -3.3
|May low C = 2.5
|Jun low C = 8.0
|Jul low C = 11.8
|Aug low C = 10.1
|Sep low C = 5.5
|Oct low C = -0.8
|Nov low C = -5.1
|Dec low C = -9.1
|year low C =
|Jan avg record low C = -27.6
|Feb avg record low C = -27.3
|Mar avg record low C = -22.3
|Apr avg record low C = -12.1
|May avg record low C = -4.3
|Jun avg record low C = 1.8
|Jul avg record low C = 5.3
|Aug avg record low C = 2.0
|Sep avg record low C = -2.5
|Oct avg record low C = -10.1
|Nov avg record low C = -16.0
|Dec avg record low C = -21.5
|year avg record low C = -29.7
|Jan record low C = -40.8
|Feb record low C = -41.7
|Mar record low C = -37.5
|Apr record low C = -26.0
|May record low C = -10.5
|Jun record low C = -1.5
|Jul record low C = 2.2
|Aug record low C = -1.8
|Sep record low C = -8.1
|Oct record low C = -23.0
|Nov record low C = -32.3
|Dec record low C = -37.3
|year record low C =
|precipitation colour = green
|Jan precipitation mm = 56.5
|Feb precipitation mm = 44.9
|Mar precipitation mm = 35.8
|Apr precipitation mm = 32.4
|May precipitation mm = 45.5
|Jun precipitation mm = 52.8
|Jul precipitation mm = 60.7
|Aug precipitation mm = 57.2
|Sep precipitation mm = 64.8
|Oct precipitation mm = 59.2
|Nov precipitation mm = 68.9
|Dec precipitation mm = 63.6
|year precipitation mm =
|Jan snow depth cm = 47
|Feb snow depth cm = 67
|Mar snow depth cm = 76
|Apr snow depth cm = 62
|May snow depth cm = 7
|Jun snow depth cm = 0
|Jul snow depth cm = 0
|Aug snow depth cm = 0
|Sep snow depth cm = 0
|Oct snow depth cm = 4
|Nov snow depth cm = 13
|Dec snow depth cm = 26
|year snow depth cm = 77
|source 1 = SMHI Open Data {{cite web|url=https://www.smhi.se/klimatdata/meteorologi/ladda-ner-meteorologiska-observationer/#param=precipitationMonthlySum,stations=all,stationid=163960|title=SMHI Open Data|publisher=Swedish Meteorological and Hydrological Institute|language=sv|access-date=10 March 2021|archive-date=11 April 2019|archive-url=https://web.archive.org/web/20190411092753/https://www.smhi.se/klimatdata/meteorologi/ladda-ner-meteorologiska-observationer#param=precipitationMonthlySum,stations=all,stationid=163960|url-status=dead}}
|source 2 = SMHI Monthly Data {{cite web|url=http://www.smhi.se/klimatdata/meteorologi/temperatur/2.1240|title=SMHI Average Monthly Data 2002–2018|publisher=Swedish Meteorological and Hydrological Institute|language=sv|access-date=10 March 2021|archive-date=2 May 2019|archive-url=https://web.archive.org/web/20190502092934/http://www.smhi.se/klimatdata/meteorologi/temperatur/2.1240|url-status=dead}}
}}
{{Weather box
|location = Oulu, 1981-2010 normals, records 1921 - present
|collapsed = yes
|metric first = yes
|single line = yes
|Jan record high C = 9.3
|Feb record high C = 7.8
|Mar record high C = 11.5
|Apr record high C = 23.9
|May record high C = 29.9
|Jun record high C = 32.3
|Jul record high C = 33.3
|Aug record high C = 30.5
|Sep record high C = 25.4
|Oct record high C = 20.5
|Nov record high C = 11.2
|Dec record high C = 8.2
|Jan high C = −6
|Feb high C = −5.7
|Mar high C = −0.9
|Apr high C = 5.6
|May high C = 12.5
|Jun high C = 17.9
|Jul high C = 20.9
|Aug high C = 18.3
|Sep high C = 12.5
|Oct high C = 5.8
|Nov high C = −0.4
|Dec high C = −4.0
|Jan mean C = −9.6
|Feb mean C = −9.3
|Mar mean C = −4.8
|Apr mean C = 1.4
|May mean C = 7.8
|Jun mean C = 13.5
|Jul mean C = 16.5
|Aug mean C = 14.1
|Sep mean C = 8.9
|Oct mean C = 3.3
|Nov mean C = −2.8
|Dec mean C = −7.1
|Jan low C = −13.6
|Feb low C = −13.3
|Mar low C = −8.8
|Apr low C = −2.6
|May low C = 3.3
|Jun low C = 9.0
|Jul low C = 12.2
|Aug low C = 10.1
|Sep low C = 5.4
|Oct low C = 0.8
|Nov low C = −5.5
|Dec low C = −10.8
|Jan record low C = -37.5
|Feb record low C = -41.5
|Mar record low C = -32
|Apr record low C = -21.4
|May record low C = -9.1
|Jun record low C = -6.1
|Jul record low C = 3.6
|Aug record low C = -1.5
|Sep record low C = -8
|Oct record low C = -20.6
|Nov record low C = -33
|Dec record low C = -37.2
|precipitation colour = green
|Jan precipitation mm = 31
|Feb precipitation mm = 26
|Mar precipitation mm = 26
|Apr precipitation mm = 20
|May precipitation mm = 37
|Jun precipitation mm = 46
|Jul precipitation mm = 71
|Aug precipitation mm = 65
|Sep precipitation mm = 44
|Oct precipitation mm = 45
|Nov precipitation mm = 36
|Dec precipitation mm = 30
|Jan precipitation days = 10
|Feb precipitation days = 8
|Mar precipitation days = 8
|Apr precipitation days = 6
|May precipitation days = 7
|Jun precipitation days = 7
|Jul precipitation days = 9
|Aug precipitation days = 10
|Sep precipitation days = 9
|Oct precipitation days = 10
|Nov precipitation days = 11
|Dec precipitation days = 10
|daily = Y
|Jan humidity = 87
|Feb humidity = 86
|Mar humidity = 82
|Apr humidity = 73
|May humidity = 67
|Jun humidity = 66
|Jul humidity = 71
|Aug humidity = 76
|Sep humidity = 82
|Oct humidity = 86
|Nov humidity = 90
|Dec humidity = 89
|year humidity = 80
|Jan sun = 24
|Feb sun = 69
|Mar sun = 137
|Apr sun = 208
|May sun = 273
|Jun sun = 296
|Jul sun = 283
|Aug sun = 212
|Sep sun = 133
|Oct sun = 69
|Nov sun = 28
|Dec sun = 8
|source 1 = FMI{{cite web|url=https://helda.helsinki.fi/bitstream/handle/10138/35880/Tilastoja_Suomen_ilmastosta_1981_2010.pdf |title=FMI normals 1981-2010|publisher=FMI |access-date=26 April 2016}}
|source 2 = FMI (record highs and lows 1961–present){{cite web
| url = http://suja.kapsi.fi/fmi-tilastot.php?taulukkomoodi=true
| title = FMI open data
| publisher = FMI
| access-date = 7 September 2019}}
FMI(record highs and lows 1921–1961){{Cite web
|url=https://helda.helsinki.fi/bitstream/handle/10138/15734/2009nro8.pdf?sequence=1&isAllowed=y|title=Suomen maakuntien ilmasto
|website=helda.helsinki.fi|access-date=4 September 2023|language=fi}}
|date=April 2016}}
Ecology
File:Maakalla ansio.jpg of the Kallankari Islands, part of Kalajoki]]
The Quark ridge at the south of the bay defines the dividing line beyond which many salt water species are unable to survive.{{sfn|Bottniska viken: Stockholms universitets}}
Instead of the red and brown algae found further south, the bay has predominantly green algae and phanerogams.{{sfn|Eleftheriou|Smith|Ansell|1995|p=23}}
Annual plant species are almost completely dominant. The only perennials are a few specimens of the freshwater cryptogam Isoetes echinospora and the moss Fontinalis dalecarlica.{{sfn|Eleftheriou|Smith|Ansell|1995|p=25}}
Often the green algae have a dense covering of epiphytic diatoms.{{sfn|Eleftheriou|Smith|Ansell|1995|p=26}}
The shores, beaches and shallows include a variety of northern plant species including the endemic yellow hair grass (Deschampsia bottnica).{{sfn|About the Bay ... Bottenvikens skärgård}}
The only filter feeders are Ephydatia and, at the river mouths, small numbers of freshwater mussels.{{sfn|Eleftheriou|Smith|Ansell|1995|p=26}}
Bivalves make up 9% of animal biomass. Crustaceans, mostly Saduria entomon make up 45% and gastropoda 30%.{{sfn|Eleftheriou|Smith|Ansell|1995|p=33}}
The gastropoda are grazing snails related to freshwater species.{{sfn|Eleftheriou|Smith|Ansell|1995|p=29}}
Fish species found in the area's lakes and rivers also live in the bay, including roach, perch, pike and grayling.{{sfn|Bottniska viken: Stockholms universitets}}
Ringed seal, grey seal, cod, herring and salmon may also be found in the bay.{{sfn|About the Bay ... Bottenvikens skärgård}}
In the 16th century seals were hunted in the Bay of Bothnia. Ringed seals were captured using nets in the inshore open water, and were stalked and captured in their dens or at breathing holes. Both grey and ringed seals were hunted along the edge of the ice.{{sfn|Kvist|1991|p=339}}
Wild vendace roe harvested from the Kalix River, known as Kalix Löjrom or as sea gold,
is a delicacy with a European protected designation of origin.{{sfn|Swedish Lapland: The destination}}
Birdlife includes the black guillemot, velvet scoter, oystercatcher, lesser black-backed gull, western capercaillie and willow ptarmigan.
Moose and hare are found on the islands, as on the mainland.{{sfn|About the Bay ... Bottenvikens skärgård}}
Occasionally, whales have been observed in the Bothnian SeaYle Uutiset. 2006. [https://yle.fi/uutiset/osasto/news/humpback_whale_spotted_in_gulf_of_bothnia/5226915 Humpback Whale Spotted in Gulf of Bothnia]. Retrieved on September 05, 2017 and remains of extinct Atlantic gray whale was found from GräsöJones L.M..Swartz L.S.. Leatherwood S.. [https://books.google.com/books?id=GfGITi5NmJoC&dq=bothnia+whale&pg=PA41 The Gray Whale: Eschrichtius Robustus]. "Eastern Atlantic Specimens". pp 41-44. Academic Press. Retrieved on September 05, 2017 while it is not clear whether or not whales might once have reached Bothnian Bay historically.
Population
File:Raahe Old Town 2008 07 10.JPG
Ports on the Finnish side include Haukipudas, Jakobstad, Kemi, Kokkola, Oulu, Raahe and Tornio.{{sfn|Bothnian Bay: Port Map}}
The largest towns by population on the Finnish side as of 2013 were Oulu (192,680), Tornio (22,374), Kemi (22,157), Kempele (16,549), Raahe (25,641), Kalajoki (12,637), Kokkola (46,697) and Jakobstad (19,636).{{sfn|Väestötietojärjestelmä Rekisteritilanne}} In Finland the catchment area included about {{convert|544000|ha}} of arable land as of 1993. There were four Finnish pulp and paper mills, of which two (Veitsiluoto Oy and Metsä Botnia Oy) were producing bleached kraft paper.{{sfn|Baltic Sea Joint Comprehensive Environmental Action|pp=2-3}}
On the Swedish side ports include Haparanda, Karlsborg, Kalix, Luleå, Piteå and Skellefteå.{{sfn|Bothnian Bay: Port Map}}
The largest towns on the Swedish side as of 2013 were Luleå (74,000), Skellefteå (71,641), Piteå (40,860) and Kalix (16,926).
Luleå is the largest city in Norrbotten, with the largest airport. The 1,312 islands of the Luleå archipelago are an important tourist attraction, as is the Gammelstad church village, listed as a Unesco World Heritage site.{{sfn|Swedish Lapland: The destination}} As of 1993 there were about {{convert|113000|ha}} of arable land in the Swedish part of the catchment basin, mostly used for small-scale low-intensity farming. There were five pulp and paper mills, of which one produced bleached kraft paper.{{sfn|Baltic Sea Joint Comprehensive Environmental Action|pp=2-3}}
In the late 1960s the bay was being used to transport fuel oil to the Finnish settlements around the bay. In 1968 about 950,000 tons of cellulose and 230,600 tons of paper and cardboard were exported, a figure that was rising.{{sfn|Mäkinen|1972|p=4}} In 1968 ships calling at the Finnish ports carried about 388,872 tons of iron bars and 64,326 tons of steel sheets. Mining and mineral products such as coal and ore were carried to and from the ports, and steel products were exported.{{sfn|Mäkinen|1972|p=5}}
Sea transport continued throughout the winter.{{sfn|Mäkinen|1972|p=4}} In 1993 there were two non-ferrous heavy metal smelters, in Rönnskär and Kokkola, emitting significant quantities of heavy metals. Efforts were being made to reduce emissions. The drainage basin also held three iron and steel plants and a number of mines.{{sfn|Baltic Sea Joint Comprehensive Environmental Action|pp=2-3}}
Human activities have affected the fragile sub-arctic environment. Dredging and other activities related to sea transport affect marine life.
Agriculture, forestry and peat mining in the catchment basin add nutrients to the bay, affecting the ecological balance, while pollutants are delivered from steel mills and from pulp and paper mills around the bay, as well as from sewage treatment plants.{{sfn|Laine|2013|p=1}} Steel mills and stainless steel plants may have released nickel and chromium.{{sfn|Szefer|2002|p=11}} Efforts have been made to reduce pollution through improved technology, but some areas along the Finnish coastline show evidence of eutrophication.{{sfn|Laine|2013|p=1}} Compared to other parts of the Baltic, higher levels of nitrate have been found in the Bothnian Bay and lower levels of phosphate and silicates.{{sfn|Szefer|2002|p=134}}
Gallery
File:Seskaro bridge.jpg|The bridge to Seskarö, Sweden
File:Icebreaker Fennica.jpg|Finnish icebreaker MSV Fennica in the Bay
File:SampoIceTrac.JPG|Looking back from the Icebreaker Sampo near Kemi, Finland
File:Outokumpu mill in Tornio 20121015.jpg|Outokumpu mill in Tornio
File:Oulu Toppila.jpg|Old mill buildings and harbour in Toppila, Oulu, Finland
File:20080227 Varessäikkä Siikajoki.jpg|Buildings and the birdwatching tower at Varessäikkä harbour, Siikajoki, Finland
File:Mökki Pallosessa.jpg|Old fisherman's cottage
File:Lönkytin.jpg|Lönkytin island
File:Kahvankari Oulu.jpg|The island of Kahvankari in Oulu, Finland
File:Kraaseli in Kello.JPG|The eastern shore of the Kellon Kraaseli island, Haukipudas, Finland
File:Bothnian Bay Kemi.jpg|Bothnian Bay in Kemi, Finland
File:Auringonlasku.jpg|Sunset at Hiekkasärkät, Kalajoki, Finland
References
Citations
{{reflist|colwidth=30em}}
{{commons category|Bothnian Bay}}
Sources
{{refbegin}}
- {{cite web|ref={{harvid|About the Bay ... Bottenvikens skärgård}}|url=http://www.swedishlapland.com/en/Bottenvikens-skargard/info/Information/|title=About the Bay of Bothnia|work=Bottenvikens skärgård|access-date=2013-09-30|url-status=dead|archive-url=https://web.archive.org/web/20131005023046/http://www.swedishlapland.com/en/Bottenvikens-skargard/info/Information/|archive-date=2013-10-05}}
- {{cite web|url=http://www.diva-portal.org/smash/get/diva2:1378/FULLTEXT01.pdf|publisher=Mid-Sweden University|last=Ankre|first=Rosemarie|access-date=2013-10-04|title=A Case Study of the Luleå archipelago, Sweden|year=2005}}
- {{cite web |ref={{harvid|Baltic Sea Joint Comprehensive Environmental Action}} |url=http://www.baltic.vtt.fi/demo/bot_bay/ |title=Baltic Sea Joint Comprehensive Environmental Action Programme |location=Helsinki |year=1993 |publisher=Balt. Sea Environ. Proc. No. 48 |access-date=2013-10-02 |archive-url=https://web.archive.org/web/20160303205051/http://www.baltic.vtt.fi/demo/bot_bay/ |archive-date=2016-03-03 |url-status=dead }}
- {{cite web|ref={{harvid|Bay of Bothnia National Park}}|url=http://www.lapland-travel-info.com/Bay-of-Bothnia-national-park.html|title=Bay of Bothnia National Park|work=Lapland Travel Info|access-date=2013-09-30|archive-url=https://web.archive.org/web/20140904011040/http://www.lapland-travel-info.com/Bay-of-Bothnia-national-park.html|archive-date=2014-09-04|url-status=dead}}
- {{cite web|ref={{harvid|Bothnian Bay: Port Map}}|url=http://www.worldportsource.com/waterways/Bothnian_Bay_290.php|title=Bothnian Bay: Port Map|work=World Port Source|access-date=2013-10-01|archive-date=5 October 2013|archive-url=https://web.archive.org/web/20131005013621/http://www.worldportsource.com/waterways/Bothnian_Bay_290.php|url-status=dead}}
- {{cite web|ref={{harvid|Bottniska viken: Stockholms universitets}}|url=http://www.havet.nu/?d=42|work=Havet.nu|title=Bottniska viken|access-date=2013-09-30|publisher=Stockholms universitets Östersjöcentrum and Umeå marina forskningscentrum}}
- {{cite book|last1=Eleftheriou|first1=Anastasios|last2=Smith|first2=Christopher|last3=Ansell|first3=Alan D.|title=Biology and Ecology of Shallow Coastal Waters: Proceedings of the 28th European Marine Biology Symposium, Institute of Marine Biology of Crete, Iraklio, Crete, 1993|url=https://books.google.com/books?id=ZSKgLpt3GcEC&pg=PA23|access-date=2013-09-30|year=1995|publisher=Olsen & Olsen|isbn=978-87-85215-28-4}}
- {{cite web|ref={{harvid|Haparanda Skärgård National Park}}|url=http://www.swedishepa.se/Enjoying-nature/Protected-areas/National-Parks/Haparanda-Skargard/|title=Haparanda Skärgård National Park|publisher=Swedish Environmental Protection Agency|access-date=2013-10-02}}
- {{cite web|ref={{harvid|Index: bottenviken.se}}|url=http://www.bottenviken.se/index.html|title=Index|work=bottenviken.se|access-date=2013-10-02}}
- {{cite journal|last=Kvist |first=Roger |title =Sealing and sealing methods in the Bay of Bothnia, 1551–70 |journal =Polar Record
|volume =27 |issue =163 |pages=339–344
|date=October 1991 |issn =1475-3057 |doi =10.1017/s0032247400013097|bibcode=1991PoRec..27..339K |s2cid=129763552 }}
- {{cite web|url=http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search.dspPage&n_proj_id=1846&docType=pdf|last=Laine|first=Anne|year=2013|title=Bothnian Bay Life – Integrated Management System for the Bothnian Bay|access-date=2013-10-02}}
- {{cite book|last1=Leppäranta|first1=Matti|last2=Myrberg|first2=Kai|title=Physical Oceanography of the Baltic Sea|url=https://books.google.com/books?id=csLKtvZNV98C&pg=PA55|access-date=2013-10-01|date=2009-03-20|publisher=Springer|isbn=978-3-540-79703-6|page=55}}
- {{cite web |url=http://deepblue.lib.umich.edu/bitstream/handle/2027.42/91740/Publication_No_132.pdf?sequence=1 |last=Mäkinen |first=Pentti |date=September 1972 |title=Winter Navigation in the Bothnian Bay and the Iceworthiness of Merchant Vessels |publisher=U.S. Department of Commerce |access-date=2013-10-02 }}
- {{citation |ref={{harvid|Merikartta Perämeri osa 57}}
|title=Merikartta Perämeri osa 57 (Nautical chart of the Bay of Bothnia 57)}}
- {{cite book|last=Müller|first=K.|title=Coastal Research in the Gulf of Bothnia|url=https://books.google.com/books?id=fc4EJ9O8NtUC&pg=PA2|access-date=2013-09-30|date=1982-04-30|publisher=Springer|isbn=978-90-6193-098-3}}
- {{cite web |last=Nesje |first=Atle |url=http://www.cicero.uio.no/fulltext/index_e.aspx?id=4182 |title=Isbreene smelter – havnivået stiger |publisher=CICERO |date=2006-05-30 |access-date=2012-08-18 |archive-url=https://web.archive.org/web/20130620075926/http://www.cicero.uio.no/fulltext/index_e.aspx?id=4182 |archive-date=2013-06-20 |url-status=dead }}
- {{cite web|url=http://wwwp.ymparisto.fi/perameri/html/fin/pmfakta.htm|publisher=Bothnian Bay Life project|last=Nordström|first=Marie|access-date=2013-09-30|title=Perämeri|date=4 December 2009|url-status=dead|archive-url=https://web.archive.org/web/20050928075742/http://wwwp.ymparisto.fi/perameri/html/fin/pmfakta.htm|archive-date=28 September 2005}}
- {{citation
|last=Røed|first=Lars-Ludvig |title=Norge blir stadig høyere |work=Aftenposten |date=4 November 2011}}
- {{cite book|ref={{harvid|Sweden: Rough Guides 2003}}|title=Sweden|url=https://books.google.com/books?id=PgxgwGSwFrEC&pg=PA403|access-date=2013-10-02|year=2003|publisher=Rough Guides|isbn=978-1-84353-066-4}}
- {{cite web |ref={{harvid|Swedish Lapland: The destination}} |url=http://www.sldmc.com/destination/ |title=Swedish Lapland: The destination |publisher=Swedish Lapland DMC |access-date=2013-10-02 |archive-url=https://web.archive.org/web/20160329204436/http://www.sldmc.com/destination/ |archive-date=2016-03-29 |url-status=dead }}
- {{cite book|last=Szefer|first=P.|title=Metals, Metalloids and Radionuclides in the Baltic Sea Ecosystem|url=https://books.google.com/books?id=SJZ-UtLXjb0C&pg=PA134|access-date=2013-09-30|date=2002-01-30|publisher=Elsevier|isbn=978-0-08-053633-0}}
- {{cite web
|ref={{harvid|Väestötietojärjestelmä Rekisteritilanne}}
|url=http://vrk.fi/default.aspx?docid=7675&site=3&id=0
|title=Väestötietojärjestelmä Rekisteritilanne
|date=31 August 2013
|language=fi, sv
|publisher=Population Register Center of Finland
|access-date=2013-10-02
|url-status=dead
|archive-url=https://web.archive.org/web/20130928214308/http://www.vrk.fi/default.aspx?docid=7675&site=3&id=0
|archive-date=2013-09-28
}}
{{refend}}
{{List of seas}}