The Onyx River is the longest river in Antarctica, flowing for 19 miles from the coastal Wright Lower Glacier and ending in Lake Vanda.
The Onyx River, in Wright Valley, is a seasonal stream of meltwater which flows for some 40 km from coastal piedmont glaciers inland into Lake Vanda. The stream bed is mainly braided in fine alluvial gravels, with some stretches of coarser moraine materials. A number of tributary feeders flow from the alpine glaciers of the ranges bordering the valley. Seasonal flows have been regularly monitored from two portions of the river. The Lower Wright site, close to the headwaters of the river, is about 2 km downstream from the shallow Lake Brownworth at the terminus of the Lower Wright Glacier. It is upstream from the confluence with the tributary streams and hence records only the flow contribution from the Lower Wright Glacier. The Vanda Weir is about 500 m upstream from the mouth of the river at Lake Vanda and also contains water from the Clark, Meserve and Bartley glacier streams.
There are no fish in the Onyx River, but it supports microscopic life, and the algal blooms can be quite extensive. The environment consists mainly of cyanobacteria and other algae. A few small animals (nematodes, tardigrades, and rotifers) live in the river. Skuas are also occasionally present in the area.
Picture Credit : Google
