| 词条 | Ablation Valley |
| 释义 |
ClimateThe climate of the area is affected by easterly-moving cyclonic depressions of the Southern Ocean. These depressions make the weather relatively mild; bring strong northerly winds and a heavy cloud cover to the region. The climate is also characterized by continental north to northwesterly flow of cold anticyclone air from the West Antarctic Ice Sheet. This flow brings clear, cold and stable conditions, relatively light winds from the south, and negative temperatures. The mean summer temperature recorded in the early 1970s was estimated as just below 0{{nbsp}}°C (32{{nbsp}}°F). The mean annual temperature was estimated at around -9{{nbsp}}°C (16{{nbsp}}°F) in the same time period. There is also a little snow falling in summer. The area is mostly free of snow by the end of summer. Ecology of fresh waterThere are lots of lakes, ponds and streams that are rich in benthic flora. The period from late December until February is the season when running water appears from three main sources. Those are: downfalls, melting of glaciers and from melting of the George VI Ice Shelf. Streams are usually several kilometers in length, and they run through glaciers and snowfields. The main streams flow down into Ablation Lake and Moutonnee Lake. In summer period there are surface melt water pools formed in hollows between lake ridges. Many elongated pools and ponds vary in length from 10 to 1500 m and up to 200 m in width, and have depths ranging from 1 to 6 m. The level of these pools and ponds rise in the melt period. However, water may drain through sub-ice fissures that open in the ice shelf. Turbidity of pools/ponds depends on the presence of glacial sediments. In summer large ponds are usually covered with ice in some parts, whereas pools are usually free of ice in this period. On the territory of the valley there are numerous ponds that have depth of 1 to 15 m. Lots of these ponds are covered with moss, sometimes down to 9 m in depth. Campylium polygamum and Dicranella mostly dominate and have a length of 30 cm. There are also such species as Bryum pseudotriquetrum, Distichium capillaceum that grow at or below 1 m in depth. In the 0.5-5.0 m depth zone moss cover can reach 40-80%, and dense cyanobacterial felts that are up to 10 cm thick often cover most of the left area. The main representatives of these cyanobacterial felts are Calothrix, Nostoc and Phormidium. Birds in the areaExplorers have seen south polar skuas (Catharacta maccormicki). The birds nest close to moist and vegetated areas. Also, snow petrels (Pagodroma nivea) have been found breeding close to the Ablation Point. Scientific activities
See also
References1. ^{{cite web |url= http://www.ats.aq/documents/recatt/Att188_e.pdf|title= Ablation Valley and Ganymede Heights, Alexander Island |accessdate=2013-09-11 |work=Management Plan for Antarctic Specially Protected Area No. 147: Measure 1 |first= |last= |publisher=Antarctic Treaty Secretariat |year=2002}} {{usgs-gazetteer|id=25}}{{Antarctic Specially Protected Areas}}{{Coord|70|48|S|68|30|W||display=title}}{{AlexanderIsland-geo-stub}}2. ^{{cite web|title=Ablation Valley and Ganymede Heights, Alexander Island|url=http://www.ats.aq/documents/recatt/Att523_e.pdf|work=Management Plan for Antarctic Specially Protected Area No. 147|accessdate=2 April 2014}} 3 : Valleys of Antarctica|Landforms of Alexander Island|Antarctic Specially Protected Areas |
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