Lake Abashiri (網走湖, Abashiri-ko) is a meromictic lake[1] in Abashiri, Hokkaidō, Japan.[2] It is located in Abashiri Quasi-National Park. The Abashiri and Memanbetsu Rivers flow into the lake. Water exits the lake through the Abashiri River again and flows 7 kilometres (4.3 mi) to the Sea of Okhotsk.[3]
| Lake Abashiri 網走湖 | |
|---|---|
 A view from Mount Tento (July 2013) | |
  Lake Abashiri 網走湖 | |
| Location | Abashiri, Hokkaidō, Japan |
| Coordinates | 43°58′N 144°10′E / 43.967°N 144.167°E |
| Lake type | Dimictic |
| Primary inflows | Abashiri River and Memanbetsu River |
| Primary outflows | Abashiri River |
| Catchment area | 1,380 km2 (530 sq mi) |
| Basin countries | Japan |
| Surface area | 33 km2 (8,200 acres) |
| Average depth | 7.2 m (24 ft) |
| Max. depth | 16.1 m (53 ft) |
| Water volume | 0.2327 km3 (0.0558 cu mi) |
| Residence time | 0.43 years |
| Shore length1 | 44 km (27 mi) |
| Surface elevation | 0.4 m (1.3 ft) |
| Frozen | December to April |
| Islands | none |
| Settlements | Abashiri |
| 1 Shore length is not a well-defined measure. | |
History and formation
editFrom core samples taken from the lake bed, the lake basin appears to have first formed some 20,000 years ago during the last period of glaciation. During the last 6000 years, the Abashiri River carved out the lake bed. Artifacts from the Jōmon period have been found in the area around the Memanbetsu River. In modern times, the course of the Abashiri River has been straightened to provide for irrigation resulting in a serious siltation problem for the lake.[3]
Freezing and salinity
edit
The lake freezes over from December to April with ice up to a meter thick. The reduced inflow of water during the winter season causes saltwater to flow upstream from the Sea of Okhotsk and into the lake. This influx of saltwater has created a layer of saline water with 10,000 ppm of chlorine, 10 metres (33 ft) below the surface of the lake[3] with a freshwater upper layer that makes up 46% of the volume of the lake.[1]
Fauna
editThe wakasagi (Hypomesus nipponensis)[4] and corbicula (Corbicula japonica)[1] are common in the lake.
References
edit- ^ a b c Kuwabara, Ren (June 2001). "Long-term changes in the aquatic biota of Lake Abashiri, a meromictic lake in northeastern Hokkaido, Japan". Lakes and Reservoirs: Research and Management. 6 (2): 175–181. doi:10.1046/j.1440-1770.2001.00141.x.
- ^ "Data Summary: Abashiri-ko (Lake Abashiri)". World Lakes Database. International Lake Environment Committee. Archived from the original on 2008-05-26. Retrieved 2009-05-07.
- ^ a b c "ABASHIRI-KO (LAKE ABASHIRI)". World Lake Database. International Lake Environment Committee. Archived from the original on 2010-07-02. Retrieved 2009-05-07.
- ^ Masaru, T. (1999). Life history polymorphism and the population dynamics of wakasagi (Hypomesus nipponensis) in Lake Abashiri, Hokkaido, Japan. Scientific Reports of Hokkaido Fisheries Experimental Station 56 1-117.
