East Antarctic Tundra Ecoregion
The Budd, Knox, and Sabrina Coasts of East Antarctica were first reported by the U.S. Exploring Expedition in 1840. They are all part of Wilkes Land, named for the officer in charge of the expedition. From west to east, the Knox Coast extends from Cape Hordern (S66o15’ E100o31’), to the Hatch Islands (S66o32’ E109o16’), the Budd Coast extends from the Hatch Islands to Cape Waldron (S66o34’ E115o33’), and the Sabrina Coast extends from Cape Waldron to Cape Southard (S66o E122o3’). Cape Poinsett (S65o46’ E113o13’), Cape Folger (S66o8’ E110o44’), and Cape Nutt (S66o38’ E108o12’) were first observed by the US Exploring Expedition. With the exception of the Antarctic Peninsula in West Antarctica, Cape Poinsett is the furthest north point of continental Antarctica. Inland of these points, the East Antarctic Ice Sheet in Wilkes Land reaches elevations of 6,000 to 9,500 feet above sea level.
Up until recently, the East Antarctic Ice Sheet at Wilkes Land has been assumed to be the most stable part of Antarctica and the least likely to melt with global warming. The glaciers discharging in Wilkes Land were thought to be grounded at bedrock and isolated from warm ocean water currents. Recent research suggests this assumption is wrong.
In this map area, the majority of glaciers with ocean termini retreated between 2000 and 2012. Wilkes Land overlies a large subglacial basin which is connected to the sea. Miles, Stokes, and Jamieson (2016) suggest that the glacial retreat is related to a reduction in sea ice, which increases the incursion of warm deep water toward the glacier terminus. If this is the cause of the retreat, it is likely that ice loss from Wilkes Land would be a major contribution to sea level rise.
Greene et al. (2017) and Rintoul et al. (2016) studied the Totten Glacier (S67o0’ E116o20’) on the Sabrina Coast and found that glacial retreat is due to incursion of warm water to the grounding line of the glacier. This is the point where the glacier transitions to an ice shelf. Rintoul et al. (2016) found that a deep trough is allowing the warm water to reach the glacier under the sea ice. Greene et al. (2017) found another mechanism, increased wind, could also allow warm water to reach the grounding line. Atmospheric carbon dioxide increases will cause surface winds to intensify around Antarctica. Increased wind on the ocean surface would cause warm deep water to upwell, surmount the continental shelf, and melt the ice from below. This appears to be happening to the Totten Glacier and is a cause for concern because the glacier drains a vast basin, most of which is below sea level. Thus, Totten Glacier is believed subject to rapid collapse, potentially causing a sea level rise worldwide of 3.5 m.
The ice cap at Law Dome (S66o44’ E112o50’) on the Budd Coast rises to 1,395 m in elevation and has been the subject of climate research for several decades. Recently, it was determined that when Western Australia suffers a drought, Law Dome experiences heavy snowfall. The pattern is so intense that it is outside the range of natural variation observed for the area in the last 750 years (van Ommen and Morgan, 2010; Berardelli, 2010). Cores from the ice cap have been useful in studying atmospheric carbon dioxide levels because the heavy snowfall allows delineation of individual yearly layers. Data from the ice cores indicates that preindustrial carbon dioxide levels going back to 1006 ACE ranged from 275 to 284 ppm, with lower levels between 1550 and 1800 A.D. (Etheridge et al., 1998). Studies of methanesulfonic acid as a proxy for biological activity indicate that there has been a 20% decline in sea ice extent in East Antarctica since 1950; before 1950, sea ice was routinely 1 degree of latitude further north in extent (Curran et al., 2003; Wolff, 2003).
Australia’s Casey Station (S66o17’ E110o32’) is located in the Windmill Island area and used for scientific research on bedrock geology and structure of the East Antarctic ice sheet, ocean acidification, Adelie penguins, and moss beds (http://www.antarctica.gov.au/living-and-working/stations/casey).
On the Budd Coast in the Windmill Islands area are four specially protected areas.
Antarctic Specially Protected Area (ASPA) 103: Ardery Island (S66o22’ E110o27’) and Odbert Island (S66o22’ E110o32’) protect breeding colonies of four species of fulmarine petrels, Antarctic petrel, southern fulmar, cape petrel, and snow petrel. These birds typically nest on cliffs. Other breeding bird populations are Wilson’s storm petrel and Antarctic skua. On Odbert Island is a breeding population of Adelie penguins. Vegetation is moss, lichen, and algae. The 244-ha site is an Important Bird Area.
ASPA 135: Northeast Bailey Peninsula (S66o17’ E110o32’) is the most important botanical sites in Antarctica, used for scientific reference studies. The 28-ha site is just to the east of Casey Station. The low rounded ice-free rocky outcrops include three extensive moss fields, lichens, bryophytes, algae, and fungi.
ASPA 136: Clark Peninsula (S66o15’ E110o36’) is 940 ha noted for its extensive floral community and significant breeding populations of Adelie penguins and south polar skuas. Flora includes lichen, moss, bryophyte, algae, and cyanobacteria.
ASPA 160: Frazier Islands include three small islands with a total area of 60 ha. In combination, the three islands provide the largest known breeding colony of the southern giant petrel. Also breeding on Nelly Island (S66o14’ E110o11’) are snow petrel, cape petrel, Antarctic petrel, Wilson’s storm petrel, southern fulmar, and South Polar skua. On Dewart Island (S66o14’ E110o10’), the cape petrel also breeds. Charlton Island (S66o13’ E110o9’) is the smallest of the islands in the protected area.
On the Knox Coast is the Bunger Hills area with two historic sites. The Bunger Hills are generally ice-free. Historic Site and Monument 10: Soviet Oasis Station Observatory (S66o16’ E100o45’) is a magnetic observatory building from 1956. HSM 49: Bungar Hill Pillar (S66o16’ E100o45’) is a concrete monument established by the first Polish Antarctic expedition in 1959, which measured acceleration due to gravity.
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