Onyx River

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Onyx River
Onyx River.png
Onyx river Map
Origin Lake Brownworth
Mouth Lake Vanda
Basin countries Antarctica
Length 32 km (20 mi)

The Onyx River is an Antarctic meltwater stream which flows westward through the Wright Valley from Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda, during the few months of the Antarctic summer. Despite being only 32 kilometres (20 mi) in length it is the longest river in Antarctica.[1]

Geography[edit]

The Onyx river flows away from the ocean, an example of endorheic drainage, as the Wright Glacier blocks the entrance to the valley. It has several tributaries, and there are multiple meteorological stations along the length of the river. Flow levels are highly variable, both during the day and between summers, with the river failing to reach the lake some years. In contrast, it can cause significant erosion in flood years, and was rafted in 1984 by New Zealand researchers. At one time, the river's discharge reached 700 cubic feet per second (20 m3/s)[2]

Environment[edit]

While there are no fish in Onyx River, it does support microscopic life, and the algal blooms can be quite extensive. The environment consists mainly of Cyanobacteria and other algae. Aside from gulls which occasionally visit, Nematodes, Tardigrades, and Rotifers are the only fauna of the Onyx river.[3]

Monitoring[edit]

The Onyx River is one of the many sites studied by the United States Antarctic Program of the National Science Foundation. The Antarctica New Zealand program once maintained a semi-permanent camp at Lake Vanda which has since been removed. Currently there is a small research shelter at Lake Vanda at its eastern end. Nearby is the Comprehensive Test Ban Treaty Seismic station at Bull Pass.

Onyx River flowing into Lake Vanda
Map of Wright Valley with Onyx River and Lake Vanda

See also[edit]

References[edit]

  1. ^ Nick Middleton. Rivers: A Very Short Introduction. (page 26) ISBN 9780199588671
  2. ^ [1]. The Antarctic Sun. 27 September 2013. Retrieved 18 April 2015
  3. ^ Diane M. McKnight, Dev K. Niyogi, Alexander S. Alger, Arne Bomblies, Peter A. Conovitz and Cathy M. Tate, "Dry Valley Streams in Antarctica: Ecosystems Waiting for Water", Oxford Jourals, Retrieved 2015-3-25

External links[edit]

  • "Antarctica’s longest river", p 16, and "What the flood revealed", pp 15–21, Antarctic Sun, January 26, 2003

Coordinates: 77°32′00″S 161°34′01″E / 77.5333°S 161.567°E / -77.5333; 161.567