|Lakes and Streams|
The Dry Valleys contain Antarctica’s longest and largest river, the Onyx.Perhaps counter-inuitively, the Dry Valleys contain Antarctica’s longest and largest river, the Onyx. The flow of the Onyx has been measured almost constantly since 1970, and the Long Term Ecological Research project also monitors a number of other streams in the Taylor and Wright Valleys. These water flows occur only in summer, with almost all the water provided by glacial melt.
Various forms of lakes and ponds are found throughout the region. ‘Dry bottomed’ lakes such as Lake Vida freeze completely solid in winter, while most of the larger lakes retain some liquid at their base. Most lakes have an ice covering all year round, although a ‘moat’ may form around the edges. The ice covering protects the water from disturbance by wind, so that very stable layers of water with distinct physical and chemical properties can form. Mircobial communities live in the water column and on the lake floors. Many of the lakes have inflows of water with no outlet, resulting in a briny layer of water at the bottom. In smaller water bodies (hypersaline ponds) the salt content can be so high the water does not freeze at all.
LinksMcMurdo Dry Valleys Long Term Ecological Research
Image: Wright Valley © Andris Apse, Antarctica NZ Pictorial Collection: K211 07/08