Wikipedia
Lake Akan
Lake Akan (阿寒湖, Akan-ko) is a lake in Kushiro, Hokkaidō, Japan. It is located in Akan National Park and is a Ramsar Site.[2][3]
| Lake Akan | |
|---|---|
The view from Mount Oakan (July 2008) | |
Lake Akan | |
| Location | Kushiro, Hokkaidō, Japan |
| Coordinates | 43°27′6″N 144°5′55″E / 43.45167°N 144.09861°ECoordinates: 43°27′6″N 144°5′55″E / 43.45167°N 144.09861°E |
| Lake type | Dimictic |
| Native name | 阿寒湖 (Japanese) |
| Primary outflows | Akan River |
| Catchment area | 148 km2 (57 sq mi) |
| Basin countries | Japan |
| Surface area | 13 km2 (3,200 acres) |
| Average depth | 17.8 m (58 ft) |
| Max. depth | 44.8 m (147 ft) |
| Water volume | 0.23 km3 (0.055 cu mi) |
| Shore length1 | 25.9 km (16.1 mi) |
| Surface elevation | 420 m (1,380 ft) |
| Frozen | December to April |
| Islands | 4: Ōjima, Kojima, Yaitai Island, Chūrui Island |
| Settlements | Kushiro |
| Official name | Akan-ko |
| Designated | 8 November 2005 |
| Reference no. | 1540[1] |
| 1 Shore length is not a well-defined measure. | |
Two scenes of the lake in December, 2021
Lake Akan and Mount Oakan
History
Volcanic activity formed the lake some 6,000 years ago, when a lava dam was formed. The lake used to have a clarity of 8–9 meters in the 1930s. Pollution from local hotspring resorts has decreased the transparency to 3–4 meters.[4]
Flora and fauna
The lake is famous for the marimo (Aegagropila linnaei), aggregations of algae that form into spherical shapes 2–30 cm in diameter. Other flora of the lake include the following:[4]
- Phragmites communis
- Nuphar sp.
- Potamogeton crispus
- Hydrilla verticillata
- Myriophyllum verticillatum
- Vallisneria gigantea
- Melosira italica
- Asterionella formosa
- Synedra
Kokanee salmon (Oncorhynchus nerka) are native to Lake Akan. Other fauna of the lake include the following:[4]
- Zooplankton:
- Daphnia longiremis
- Bosmina coregoni
- Eurytemora affinis
- Bottom:
- Fish:
- Cyprinus carpio
- Carassius
- Hypomesus olidus
- Leuciscus hakonensis
Climate
| Climate data for Lake Akan (1991−2020 normals, extremes 1977−present) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 6.1 (43.0) | 10.8 (51.4) | 16.5 (61.7) | 28.3 (82.9) | 35.5 (95.9) | 34.5 (94.1) | 34.9 (94.8) | 33.9 (93.0) | 31.4 (88.5) | 24.5 (76.1) | 19.0 (66.2) | 11.8 (53.2) | 35.5 (95.9) |
| Average high °C (°F) | −4.2 (24.4) | −3.1 (26.4) | 1.4 (34.5) | 8.1 (46.6) | 15.1 (59.2) | 18.9 (66.0) | 22.3 (72.1) | 22.8 (73.0) | 19.0 (66.2) | 13.2 (55.8) | 5.8 (42.4) | −1.4 (29.5) | 9.8 (49.7) |
| Daily mean °C (°F) | −10.0 (14.0) | −9.4 (15.1) | −4.2 (24.4) | 2.3 (36.1) | 8.5 (47.3) | 13.1 (55.6) | 17.1 (62.8) | 18.0 (64.4) | 14.0 (57.2) | 7.5 (45.5) | 0.7 (33.3) | −6.5 (20.3) | 4.3 (39.7) |
| Average low °C (°F) | −16.7 (1.9) | −16.8 (1.8) | −10.8 (12.6) | −3.3 (26.1) | 2.3 (36.1) | 8.0 (46.4) | 12.9 (55.2) | 13.9 (57.0) | 9.3 (48.7) | 2.1 (35.8) | −4.3 (24.3) | −12.1 (10.2) | −1.3 (29.7) |
| Record low °C (°F) | −30.2 (−22.4) | −30.7 (−23.3) | −26.6 (−15.9) | −20.9 (−5.6) | −7.5 (18.5) | −3.3 (26.1) | 1.8 (35.2) | 3.2 (37.8) | −1.2 (29.8) | −7.6 (18.3) | −17.3 (0.9) | −26.9 (−16.4) | −30.7 (−23.3) |
| Average precipitation mm (inches) | 63.2 (2.49) | 44.5 (1.75) | 70.2 (2.76) | 90.8 (3.57) | 105.7 (4.16) | 84.4 (3.32) | 103.2 (4.06) | 160.0 (6.30) | 165.7 (6.52) | 137.8 (5.43) | 85.2 (3.35) | 87.4 (3.44) | 1,197.9 (47.16) |
| Average snowfall cm (inches) | 132 (52) | 96 (38) | 105 (41) | 54 (21) | 3 (1.2) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (0.4) | 31 (12) | 123 (48) | 548 (216) |
| Average precipitation days (≥ 1.0 mm) | 10.2 | 8.9 | 11.5 | 11.3 | 11.0 | 10.1 | 10.4 | 11.4 | 12.0 | 10.5 | 9.8 | 9.8 | 126.9 |
| Average snowy days (≥ 3 cm) | 12.3 | 10.4 | 12.1 | 7.0 | 0.4 | 0 | 0 | 0 | 0 | 0.1 | 3.9 | 13.0 | 59.2 |
| Mean monthly sunshine hours | 97.5 | 111.9 | 137.1 | 154.0 | 169.4 | 146.3 | 132.2 | 115.7 | 110.1 | 123.3 | 110.6 | 107.3 | 1,546 |
| Source: Japan Meteorological Agency[5][6] | |||||||||||||
See also
References
- ^ "Akan-ko". Ramsar Sites Information Service. Retrieved 25 April 2018.
- ^ . World Lakes Database. International Lake Environment Committee. Archived from the original on 2012-04-20. Retrieved 2009-05-18.
- ^ "Ramsar Sites in Japan - Akan-ko" (PDF). Ministry of the Environment. Retrieved 24 March 2011.
- ^ a b c . World Lakes Database. International Lake Environment Committee. Archived from the original on 2012-03-05. Retrieved 2009-05-18.
- ^ 観測史上1～10位の値（年間を通じての値）. JMA. Retrieved March 3, 2022.
- ^ 気象庁 / 平年値（年・月ごとの値）. JMA. Retrieved March 3, 2022.
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